AIR MATA yang menetes karena rasa malu dan muak terhadap dirinya sendiri jatuh membasahi baju Cate yang ekstrabesar. Ia tidak pernah merasa cukup dengan makanan yang ia makan. Ia terpukul oleh perasaan bersalah dan malu. Josh selalu bersikap baik kepadanya. Josh masih mempercayainya. Dan disini ia duduk dan tidak mampu berbuat apapun selain makan dan memungut artikel orang lain dari lantai. Apa yang josh tahu? Tidak ada ‘makanan terbaik bagi pelaku diet’, “ Cate beropini, dan melempar artikel itu bersama tumpukan lainnya.
Sekuat apapun ia mencoba diet, makanan selalu mengalahkannya. Kecanduan makanan yang dirasakannya adalah setan yang menggodanya dengan keinginan tak tertahankan, tidak pernah berhenti , memanfaatkan setiap kelemahannya, terus mengejarnya, membangunkannya di malam hari
Sebuah judul The Positive Effect of Zero-Calorie Carbohydrates on Craving Suppresion, Fullness and Weight Loss, dari sebuah jurnal mencuri perhatiannya. Yang menarik perhatiannya adalah karbohidrat tanpa kalori. Ia membaca judul artikel itu lebih seksama. Ia sangat berhati-hati. Ia hampir tidak percaya dengan apa yang dibacanya. Sepertinya judul itu khsus ditulis untuknya. Minatnya bangkit, ia meletakkan irisan pizza yang masih tersisa, mengeluarkan jurnal itu dari map dan mulai membacanya dengan perlahan dan seksama. Yang dibaca Cate malam itu adalah jawaban atas doa-doanya.
PIZA itu tergeletak membeku dilantai. Cate pun meluruskan punggungnya yang kaku dan bersandar ke dinding. Ia telah membaca selama 2 jam. Artikel tentang karbohidrat tanpa kalori mencengkram imajinasinya. Ia membacanya tiga kali. Kemudian ia membaca artikel lain dijurnal itu. Cate memejamkan mata dan memikirkan semua yang baru saja dibacanya.
Aku bisa memanfaatkan makanan non kalori ini untuk membebaskan diriku dari kecanduan makanan. Menyadari keahliannya dalam 2 hal, menulis dan memasak, yang bias mengubah hidupnya, ia berkata kepada dirinya sendiri, “aku bias memasak dengan makanan non kalori ini. Akubisa menulis tentang hal ini. Aku akan berhasil. Berat badanku akan berkurang berkat makanan itu. Aku bisa memanfaatkannya untuk menyelamatkan hidupku”. Cate tidak lagi merasa seperti terpenjara dalam lemak ditubuhnya. Dengan semangat dan kepercayaan diri yang baru, cate kembali mencintai dirinya.
Cate tahu dirinya telah tergerak. Penuh energi dan motivasi, ia membuang pizanya dan membersihkan noda-noda kue. Ia membuat secangkir kopi dan ia menemukan sebuah buku catatan yang bersih dan kosong. Kemudian ia duduk membuka buku catatan dan menulis My Diet Diary di halaman pertama.
Cate menghirup kopinya dan menggigit ujung pinsilnya. Lalu ia mulai menulis, awalnya memang sulit, tapi kemudian ia memperoleh kembali kepercayaan diri dan kecepatannya.
Cate mengumpulkan semua buku diet yang ia beli dan menatanya dengan rapi di atas meja dapur. Cate mencoba menghubungkan diet dengan ilmu genetika, biologi , penelitian tentang perempuan dan bahkan strategi bisnis. Walaupun lambat, ia mampu menurunkan tujuh kilogram dan dengan cepat bertambah lagi empat kilogram. Cate selalu berhasil menurunkan berat badan dengan setiap program dietnya, tapi tidak ada satu pun yang bias bertahan lama agar tubuhnya tidak kembali bertambah gemuk.
‘BAIKLAH, D.D.,’ ia menulis, ‘ aku perlu dua bagian diet. Bagian pertama adalah diet yang akan membantuku menghentikan lemak baru. Bagian kedua akan membantuku menghentikan lemak baru. Saat itulah makanan non kalori bias menunjukkan keajaibannya. Kesimpulannya, kalori dari protein adalah penghancur lemak yang potensial.
MALAM telah larut mendekati dini hari, tapi cate tidak merasa lelah sedikitpun. Hebatnya lagi, ia tidak merasa lapar. Ia mendidih, terbakar ole ide-ide, menulis dengan cepat, mencoba menuangkan semua gagasan ke dalam diary-nya. Cate mencatat di halaman kosong. Kukira yang harus dilakukan selanjutnya adalah membuat daftar bahan dan makanan yang bias digunakan untuk membuat menu dan resep penghambat lemak. Ia telah membuat semua daftarnya. Tapi kemudian pikirannya buntu dan keraguan mulai di rasakannya.
Cate merasa usaha yang ia lakukan tampak mustahil. Cate merasa gemuk, tolol, dan gagal. Emosinya naik turun tidak menentu. Dilambungkan oleh kebahagiaan. Di hempaskan oleh keputusasaan. Sesaat terisi dengan kebahagiaan dan harapan kesuksesan, lalu dikuasai oleh rasa takut akan kegagalan. Dalam kondisi emosional yang sangat lelah, cate mendesah, yang kuperlukan hanyalah sebuah pertanda, sesuatu yang menunjukkan bahwa aku berada di jalur yang tepat.
DALAM keputusasaan, Cate berdiri di depan rak buku dapur dan mulai mengeluarkan semua buku masakan yang ia kumpulkan selama bertahun-tahun, menjatuhkan mereka hingga berserakan dilantai. Saat itulah sebuah kartu terjatuh. Ia segera mengenal benda itu. Lelaki bermata ramah telah memungutnya malam itu dari samping mayat ibunya dan memberikan kepadanya. Ketika perempuan dari panti asuhan mengemasi barang-barang mereka, ia menyelipkan kartu itu kedalam buku masakan milik ibu cate. Cate menyimpan buku itu selama ini. Tidak pernah di buka dan terlupakan, buku itu adalah satu dari beberapa benda peninggalan ibunya. Kartu kecil itu, ukurannya tidak lebih besar dari telapak tangannya, membawa banyak kenangan.
Kekuatan cate pulih kembali. Ia mengambil pinsil, menulis di diarynya. Ketika menulis , ia merasa kepercayaan diri dan harapannya semakin kuat, ia merasakan kehangatan cinta dalam hatinya. Dan ia merasakan sesuatu yang lain.
Cate menyandarkan kartu bergambar roti dan ikan itu di atas meja didepannya. Sekali lagi ia merasa kepercayaan diri dan tekadnya semakin habis, maka yang tersisa hanyalah kekosongan. Tiba-tiba cate merasa sangat ketakutan karena kekosongan itu hanya bias diisi dengan makanan berlemak. Ia bisa diisi dengan makanan berlemak. Ia bisa merasakan lapar yang mulai menyiksanya.’ Ayolah, diary,’ ia memohon.’ Bantu aku. Bagaimana aku harus memulai?’ lagi-lagi, frustasi dan keputusasaan melanda Cate.
Dengan berkecil hati, gagal, dan letih, cate merasa kemenangannya sirna dan lapar kembali menyerangnya. Ia telah berusaha menjauh, tapi ternyata belum cukup jauh. ‘tidak ada gunanya,’ ia putus asa. ‘ aku tidak akan pernah bisa menyatukan dua pembasmi lemak itu dalam suatu cara yang membuat mereka bekerja dengan baik.’
Dihujani oleh insprirasi yang melimpah, cate merasa menjadi cinderlela, tinkerbell, dan mary poppons sekaligus. Setelah meletakkan jam itu di samping gambar roti dan ikan, cate mengambil diarynya lagi. Ia kini tahu pasti bagaimana ia akan melakukan dietnya agar berhasil. “dear, D.D.,” ia menulis dengan keyakinan dan kekuatan baru.
Hari dietnya sudah tiba. Ia mengatur jam wekernya enam kali sehari.
Cate yakin bahwa ia bisa melakukannya. Cate membuat daftar makanan dan cate membaca daftar makanan yang ia buat dengan seksama, memeriksa makanan apa saja yang bisa dikonsumsi untuk mengawali harinya. Dan ia mulai menilulis.
Setelah itu, cate beralih untuk memikirkan yang akan ia makan untuk waktu tengah hari hingga malam ketika jarum jam telah menunjukkan pukul dua belas siang. Cate memutuskan untuk memakan sup daging kental, atau membuat bermacam-macam salad. Makan siang adalah kenikmatan sekaligus membakar lemak. Makan siang akan menjadi makanan ke 4 dihari dietnya. Kudapan sore akan menjadi makanan ke 5 di hari dietnya.
Jari-jari tangannya terasa kaku dan sakit, ia bersandar di kursi dan melihat-lihat yang telah ia tulis. Ia merasa sangat gembira. Semua makanan yang ia tulis untuk waktu tengah malam tengah hari memang sesuai untuk pagi hari. Semua makanan yang ia tulis untuk waktu tengah hari tengah malam juga sesuai untuk sore hari dan makan malam. Satu lagi alas an bahwa dietnya memang benar-benar tepat.
Jam wekernya berdering menandakan waktunya makan rise dan shine. Sambil bersenandung, cate membuka kulkas dan mengambil jus jeruk. Ia berhenti, kotak kardus berada dalam genggamannya. Salah satu hal penting mengejutkan yang ia baca adalah bahwa kandungan karbohidrat non kalori dalam jus jeruk telah hilang ketika dip eras, seperti juga jus apel, dan semua jenis jus. Sehingga ia membuang jus itu dan ia mencari buah-buah utuh di dalam kulkas. Kemudian ia mendapatkan buah jeruk, memakannya dan mengunyah buah jeruk tersebut.
Dengan lidah yang masih merasakan segarnya jeruk, ia mengalihkan perhatiannya ke daftar bumbu makanan non kalori waktu pagi untuk melihat apa yang bisa ia masak untuk makan pagi pertamanya. Tapi kemudian ia sadar bahwa ia tidak merasa lapar yang biasa menyiksanya begitu menaruh sedikit makanan ke mulutnya. Ia merasa kenyang dan puas. Ia tidak merasa lapar terkendali. Makan pagi bisa ditunda.
Cate kembali lagi ke kamar tidur. Pada halaman diary yang kosong, dengan pena yang tidak pernah ia gunakan lebih dari setahun, ia menulis hari, Kamis, dan tanggal, 5 oktober. Setahun yang lalu tanggal itu menandai sebuah awal. Setahun kemudian ia menandai sebuah awal tentang sesuatu yang berbeda. Ia mencatat berat badannya, dan ukuran bajunya 1 x. lalu mengukur pinggangnya, pinggulnya, lingkar dadanya, lingkar pahanya, pangkal lengannya. Kemudian ia menatap dirinya di cermin sambil membayangkan dirinya langsing dan sehat.
Cate memperhatikan daftar makanan non kalori yang telah ia susun dengan cermat. Dengan jari telunjuknya menelusuri daftar, ia mencari makanan non kalori yang bisa diolahnya untuk makan pagi.
Merasa segar setelah menikmati makan pagi, cate memutuskan untuk melakukan dietnya dengan segala cara. Ia akan menata ulang dapurnya sesuai pembagian waktu. Penataan dapurnya sudah setengah jadi, ia mengeluarkan duakeranjang sampah yang penuh dengan makanan yang tidak lagi ia inginkan dan tidak lagi ia butuhkan.
Beberapa menit lebihnya dari pukul sepuluh pagi. Ia merasakan bunyi-bunyian di perutnya yang biasanya menandakan adanya serangan karbohidrat besar-besaran.
Dibentengi oleh rasa percaya diri, cate siap memulai daftar belanjaannya. Membalik lembar baru di diary dietnya, ia menulis di atas halaman, daftar makanan non kalori, dan memulai.
Sambil mengobrak-ngabrik isi kulkas, cate menyadari bahwa tidak ada banyak makanan yang tersisa setelah penataan ulang. Setelah selesai, ia mencatat makan siangnya ke dalam diary dietnya, dan kemudian mengambil daftar belanjaannya.
Kini waktunya menuliskan semua makanan untuk waktu diet tengah hari hingga tengah malam yang harus ia beli. Keju biru, keju cheddar, keju swiss, keju bubuk dan keju ricotta ia masukkan ke daftar belanja.
Sekarang giliran daftar bahan-bahan makanan yang ia perlukan untuk membuat resep masakan pagi hingga tengah hari dan tengah hari hingga malam untuk dietnya.
Dengan mendekap erat diarynya, cate berjalan memasuki pertokoan. Hari menjelang senja dan ia mulai merasa denyutan-denyutan rasa lapar yang dulu merupakan tanda akan ada pesta pora. Hati ini setiap denyutan bisa diatasi oleh pola makannya yang baru. Ia beruntung.
Dengan penuh kepuasan, cate merenungkan kembali hari diet pertama nya. Dapurnya kembali diisi persediaan makanan-makanan untuk waktu pagi yang terdiri dari makanan-makanan untuk waktu pagi yang terdiri dari makanan nonkalori yang membantunya mematikan tombol lemak, dan makanan berprotein tinggi untuk waktu setelah tengah hari yang membakar lemak yang tertimbun di tubuhnya. Cate merasakan hari yang indah karena ia bisa mengendalikan nafsu makannya.
Setelah makan malam ia menuju lantai atas sambil memeluk jam wekernya. Ia merasa kenyang, puas, dan yang paling mengherankan adalah ia tetap bertenaga. Rasa lesu yang ia rasakan sebelumnya telah di gantikan dengan energi yang melimpah,. Ia merasa hidup, terlalu gembira untuk jatuh tertidur.
Nyaring bunyi alarm membbangunkancate dari tidurnya. Itu adalah pagi pertama ia menimbang badan saat diet.
Hari berganti hari, beberapa minggu telah ia lewati. Setiap pagi timbangan itu membuatnya senang. Timbunan lemak di tubuhnya menurun drastic, demikianpun ukuran tubuhnya.
Hari-harinya ia isi dengan makanan yang lezat. Ia mencermati semua buku masakan, jurnal dan catatan-catatan lamanya untuk menemukan resep-resep yang bisa ia sesuaikan dengan pola diet pagi tengah hari dan tengah hari malam. Dengan hidangan baru, menu baru, makanan baru cate merasa tubuhnya semakin langsing, semakin kuat, semakin sehat, dan lebih hidup.
Setiap pagi selalu dimulai dengan buah-buahan. Setelah jeruk pertamanya, ia mencoba berbagai jenis jeruk, dari jeruk navel berkulit tipis, jeruk valensia, sampai jeruk berwarna merah darah. Jiak ia merasa bosan maka ia akan menggantinya dengan tangerine dan mandarin. Cate rajin memakan buah-buahan untuk menurunka berat badannya.
Cepat, sederhana, dan memuaskan , makan pagi menjadi makanan kesukaannya. Cate menjadi lebih selektif dalam memilih makanan nya misalnya seperti makanan non kalori.
Setiap pagi, antara makan pagi dan makan siang, ia mengisi perutnya dengan lebih banyak makanan non kalori. Sepanjang pagi, selama cate memasak dan bereksperimen dengan resep-resep baru, ia merasa kenyang dan puas.
Makan siangnya bervariasi, dari makanan yang sederhana sampai yang aneh-aneh. Cate selalu membuat makanan sesuai kreasinya sendiri. Ia selalu bereksperimen dengan berbagai macam makanan.
Setelah makan siang, ia mengalihkan perhatian ke kudapan sore. Kini imajinasinya dari keahlian memasaknya telah terlatih. Ia meracik dan menikmati potongan keju-keju favoritnya yang dihiasi dengan bawang acar atau asinan jamur atau crudites.
Cate berbelanja banyak untuk makan malamnya. Cate sangat bersemangat dalam membuat makan malam nya tersebut. Dengan semua makan malam yang ia buat sendiri, cate kembali menjadi koki yang kreatif dan bergairah.
Pada minggu-minggu pertama, cate memasak dan makan dan total lemak yang ia hilangkan adalah empat kilogram. Berat badannya turun. Cate sangat berusaha untuk membuat tubuhnya menjadi langsing.
Pada minggu pertama di bulan januari, cate menerima dua pucuk surat. Surat pertama dari pengacaranya, memberitahukan bahwa carles telah mendapat pekerjaan dan surat kedua datang dari orang suruhan charles. Dengan bermaksud rujuk kembali untuk merayakan awal tahun, ia mengundang cate untuk mengunjunginya pada akhir pekan.
Cate selalu merasa berkurang berat badannya hari demi hari. Cate tetap yakin bahwa berat badannya yang tidak mau turun disebabkan oleh stress.
Charles menhubungi cate untuk memberitahukan kedatangannya pada cate. Berat badan cate bertambah lagi satu setengah kilogram.
Cate mencoba untuk tidak putus asa. Ia butuh kebahagiaan untuk pertemuan pertamanya dengan charles. Cate terkadang merasa bahwa bentuk tubuh yang ia dapat kembali menghianatinya. Tapi cate menenangkan dirinya.
Tibalah saat nya. Charles berdiri di beranda sambil menggendong bayinya. Cate bisa melihat wajah Mrs. Bea di balik tirai.
Cate duduk didalam mobilnya, melihat pintu rumah itu tertutup lagi untuk dirinya. Di balik pintu itu terdapat semua hal yang ia cintai, semua yang ia inginkan. Ia merasa perlakuan charles tidak adil baginya.
Sudah berjam-jam , ia tidak pulang juga. Ia haus dan lelah. Ia telah berjuang susah payah, dan ia gagal. Charles, yang terhasut oleh Mrs. Bea akan memperjuangkan bayi mereka dan ia akan menang. Dalam keputus asaannya, ia percaya bahwa charles memang benar. Ia selalu terobsesi dengan makanan dan masih terobsesi. Ia telah membangun seluruh hidupnya untuk the cookery dan makanan, dan kini makanan telah menghianatinya, tidak hanya sekali tapi dua kali.
Semua telah berakhir. Ia telah kalah dalam pertarungan mempertahankan keluarganya, dan kini ia kalah dalam pertarungan dengan tubuhnya sendiri. Betapa salah ia menilai keadaannya selama ini. Ia mengira punya solusi-solusi yang ajaib, sementara para ahli mencoba dan gagal menemukan diet yang sempurna.
Cate telah menjalani hidupnya bersama dering jam weker itu berbulan-bulan, sampai kemarin setiap dering berarti ia semakin dekat dengan bayi dan suaminya. Berat badan cate turun tiga setengah kilogram setelah beberapa hari yang lalu berat badannya tidak mau turun.
Cate berpikir bagaimana mungkin berat badannya bisa turun dengan cepat. Lalu ia bertanya pada dirinya sendiri. Ia turun mengambil buku diarynya dan membuka catatan hari sebelumnya.
Benar-benar mudah, benar-benar masuk akal, ia terheran heran mengapa tidak terpikirkan sebelumnya. Keseluruhan dietnya berdasar pada penyesuaian makanan dengan pola waktu, tapi ada suatu bagian penting yang ia abaikan. Ia selalu memakan makanan yang mengandung karbohidrat non kalori pada waktu pagi hingga tengah hari. Hasilnya? Ia berhasil mematikan tombol pembuat lemak ditubuhnya.
Kuncinya adalah apa yang ia makan pada malam sebelumnya dan kapan ia memakannya.
Ia yakin bahwa ia aman dari munculnya lemak baru saat ia tidur, tapi ternyata tidak. Ketika ia banyak lemaknya yang menyusut, momentum penyusutan itu mengakibatkan berat badan tetap turun. Ia tidak akan pernah lagi mengabaikan cara kerja tubuhnya, bagaimana tubuhnya mengubah makanan menjadi lemak dan lemak kembali menjadi energi. Ia tidak takut lagi terhadap makanan.
Beberapa hari kemudian cate kembali memiliki berat badan terbaiknya, lima puluh dua kilogram. Selama beberapa hari itu, ia menambahkan kudapan sebelum tidur ke jadwal dietnya. Ia belajar bahwa makana yang ia makan tidak pernah berubah. Yang berubah adalah dirinya sendiri.
Sudah waktunya cate menulis lagi. Ia duduk di kursi dapur dengan diary dietnya dan laptop kecil. Cate menulis untuk dirinya sendiri dan untuk bayinya. Mereka berdua, ia dan charlie, akan menjadi keluarga yang akan memperjuangkan dirinya. Senjatanya adalah makanan dan kata-kata
“ aku tidak percaya betapa menakjubkannya, kamu menuliskan semua dan berhasil dengan baik, kamu hebat “
Cate menyerapa pujian dan kekaguman josh seperti spons kering menyerap air. Sudah lama ia tidak melakukan hal yang berguna. Dan sudah lama tidak ada lelaki yang melihatnya seperti josh menatap dirinya saat ini.
Cate mendengar ketukan keras dari pintu depan, silih berganti dengan suara bel pintu. Bingung dan masih pening dari tidur, yang pertama kali ia pikirkan adalah bayinya dan tanpa melepas pakaian tidurnya, ia turun ke bawah lantai , menghambur ke pintu dan jatuh ke lengan josh.
Berdiri di pagi yang dingin, berselimut jaket milik josh, cate melihat kebahagian dan ke banggan di mata josh, dan ada sesuatu yang lain. Ia melihat cinta. Cate tidak merasa kedinginan lagi.
Oktober telah datang lagi. Daun-daun mengering menjadi berwarna merah keemasan, seperti kue-kue kering yang segar.
“ya, Oktober adalah bulan ketika segala sesuatu akan merakhir,” cate membalas melihat ke arah taman dan pohon-pohon yang berwarna keemasan melalui jendela dapur yang lebar. “tapi bagiku oktober bukan saja sebuah akhir. Tapi juga sebuah awal.” Ia dan josh telah menikah dan tinggal disebuah rumah di pelosok pedesaan. Anak perempuan cate tinggal bersama mereka. Ia dan josh membaptisnya dengan nama annie samantha untuk mengenang ibu dan adiknya. Charlie, nama yang ia berikan di rumah sakit telah terlupakan.
‘ Untuk ibunya
Untuk adikku
Untuk gadis kecilku
Untuk bayi di perutku
Aku mempersembahkan buku
Pertamaku
Aku menyebutnya The Diet
Lalu ia merogoh saku celemeknya dan mengeluarkan foto kecil. Itu adalah foto dirinya yang terbaru, josh yang memotret. Sambil tersenyum, ia menempatkan foto itu di kertas yang baru saja ia tulisi. Denga isyarat, cate mulai mencintai dirinya.
Hormone System and Antidepressant Laboring Which Is There Are In Book of The Diet
Human Nutrition, study of how food affects the health and survival of the human body. Human beings require food to grow, reproduce, and maintain good health. Without food, our bodies could not stay warm, build or repair tissue, or maintain a heartbeat. Eating the right foods can help us avoid certain diseases or recover faster when illness occurs. These and other important functions are fueled by chemical substances in our food called nutrients. Nutrients are classified as carbohydrates, proteins, fats, vitamins, minerals, and water.
When we eat a meal, nutrients are released from food through digestion. Digestion begins in the mouth by the action of chewing and the chemical activity of saliva, a watery fluid that contains enzymes, certain proteins that help break down food. Further digestion occurs as food travels through the stomach and the small intestine, where digestive enzymes and acids liquefy food and muscle contractions push it along the digestive tract. Nutrients are absorbed from the inside of the small intestine into the bloodstream and carried to the sites in the body where they are needed. At these sites, several chemical reactions occur that ensure the growth and function of body tissues. The parts of foods that are not absorbed continue to move down the intestinal tract and are eliminated from the body as feces.
Once digested, carbohydrates, proteins, and fats provide the body with the energy it needs to maintain its many functions. Scientists measure this energy in kilocalories, the amount of energy needed to raise 1 kilogram of water 1 degree Celsius. In nutrition discussions, scientists use the term calorie instead of kilocalorie as the standard unit of measure in nutrition.
Essential nutrition
Nutrients are classified as essential or nonessential. Nonessential nutrients are manufactured in the body and do not need to be obtained from food. Examples include cholesterol, a fatlike substance present in all animal cells. Essential nutrients must be obtained from food sources, because the body either does not produce them or produces them in amounts too small to maintain growth and health. Essential nutrients include water, carbohydrates, proteins, fats, vitamins, and minerals.
An individual needs varying amounts of each essential nutrient, depending upon such factors as gender and age. Specific health conditions, such as pregnancy, breast-feeding, illness, or drug use, make unusual demands on the body and increase its need for nutrients. Dietary guidelines, which take many of these factors into account, provide general guidance in meeting daily nutritional needs.
Water
If the importance of a nutrient is judged by how long we can do without it, water ranks as the most important. A person can survive only eight to ten days without water, whereas it takes weeks or even months to die from a lack of food. Water circulates through our blood and lymphatic system, transporting oxygen and nutrients to cells and removing wastes through urine and sweat. Water also maintains the natural balance between dissolved salts and water inside and outside of cells. Our joints and soft tissues depend on the cushioning that water provides for them. While water has no caloric value and therefore is not an energy source, without it in our diets we could not digest or absorb the foods we eat or eliminate the body’s digestive waste.
The human body is 65 percent water, and it takes an average of eight to ten cups to replenish the water our bodies lose each day. How much water a person needs depends largely on the volume of urine and sweat lost daily, and water needs are increased if a person suffers from diarrhea or vomiting or undergoes heavy physical exercise. Water is replenished by drinking liquids, preferably those without caffeine or alcohol, both of which increase the output of urine and thus dehydrate the body. Many foods are also a good source of water—fruits and vegetables, for instance, are 80 to 95 percent water; meats are made up of 50 percent water; and grains, such as oats and rice, can have as much as 35 percent water.
Carbohydrate
Carbohydrates are the human body’s key source of energy, providing 4 calories of energy per gram. When carbohydrates are broken down by the body, the sugar glucose is produced; glucose is critical to help maintain tissue protein, metabolize fat, and fuel the central nervous system.
Glucose is absorbed into the bloodstream through the intestinal wall. Some of this glucose goes straight to work in our brain cells and red blood cells, while the rest makes its way to the liver and muscles, where it is stored as glycogen (animal starch), and to fat cells, where it is stored as fat. Glycogen is the body’s auxiliary energy source, tapped and converted back into glucose when we need more energy. Although stored fat can also serve as a backup source of energy, it is never converted into glucose. Fructose and galactose, other sugar products resulting from the breakdown of carbohydrates, go straight to the liver, where they are converted into glucose.
Starches and sugars are the major carbohydrates. Common starch foods include whole-grain breads and cereals, pasta, corn, beans, peas, and potatoes. Naturally occurring sugars are found in fruits and many vegetables; milk products; and honey, maple sugar, and sugar cane. Foods that contain starches and naturally occurring sugars are referred to as complex carbohydrates, because their molecular complexity requires our bodies to break them down into a simpler form to obtain the much-needed fuel, glucose. Our bodies digest and absorb complex carbohydrates at a rate that helps maintain the healthful levels of glucose already in the blood.
Carbohydrate, any of a large group of compounds in which hydrogen and oxygen, in the proportions in which they exist in water, are combined with carbon; the formula of most of these compounds may be expressed as Cm(H2O)n. Structurally, however, these compounds are not hydrates of carbon, as the formula would seem to indicate.
Carbohydrates, as a class, are the most abundant organic compounds found in nature. They are produced by green plants and by bacteria using the process known as photosynthesis, in which carbon dioxide is taken from the air by means of solar energy to yield the carbohydrates as well as all the other chemicals needed by the organisms to survive and grow.
The carbohydrate group consists principally of sugar, starch, dextrin, cellulose, and glycogen, substances that constitute an important part of the human diet and that of many animals. The simplest of them are the simple sugars, or monosaccharides, which contain either an aldehyde or a ketone group. The most important is glucose. Two monosaccharide molecules joined together by an oxygen atom, with the elimination of a molecule of water, yield a disaccharide, of which the most important are sucrose (ordinary cane sugar), lactose, and maltose. Polysaccharides have enormous molecules made up of one type or several types of monosaccharide units—about 10 in glycogen, for example; 25 in starch; and 100 to 200 in cellulose.
Within living organisms, carbohydrates serve both essential structural and energy-storage functions. In plants, cellulose and hemicellulose are the main structural elements. In invertebrate animals, the polysaccharide chitin is the main component of the exoskeletons of arthropods. In vertebrate animals, the cell coatings of connective tissues contain carbohydrates. Cell membranes are rich in glycoproteins, and so forth. Plants use starch and animals use glycogen to store energy; when the energy is needed, the carbohydrates are broken down by enzymes.
Carbohydrates are used in the manufacture of fabrics, photographic film, plastics, and other products. Cellulose, a carbohydrate, can be converted into viscose rayon, acetate rayon, and paper products. Nitrocellulose (cellulose nitrate) is used in the production of motion picture film, cement, guncotton, celluloid, and similar kinds of plastics. Starch is used in the preparation of foods for livestock and humans; pectin, a jelling agent; gum arabic; and agar, used in the production of adhesive materials, sizing materials, and emulsions. Gum arabic is also used in demulcent medicines. Agar, a constituent of some laxatives, is also used as a thickening agent in food and as a medium for bacterial culture. Hemicellulose is used to modify paper during its manufacture. The carbohydrate dextran is a polysaccharide used in medicine as a blood-plasma-volume expander to counteract acute shock; another carbohydrate, heparin sulfate, is a blood anticoagulant.
In contrast, simple sugars, refined from naturally occurring sugars and added to processed foods, require little digestion and are quickly absorbed by the body, triggering an unhealthy chain of events. The body’s rapid absorption of simple sugars elevates the levels of glucose in the blood, which triggers the release of the hormone insulin. Insulin reins in the body’s rising glucose levels, but at a price: Glucose levels may fall so low within one to two hours after eating foods high in simple sugars, such as candy, that the body responds by releasing chemicals known as anti-insulin hormones. This surge in chemicals, the aftermath of eating a candy bar, can leave a person feeling irritable and nervous.
Many processed foods not only contain high levels of added simple sugars, they also tend to be high in fat and lacking in the vitamins and minerals found naturally in complex carbohydrates. Nutritionists often refer to such processed foods as junk foods and say that they provide only empty calories, meaning they are loaded with calories from sugars and fats but lack the essential nutrients our bodies need.
In addition to starches and sugars, complex carbohydrates contain indigestible dietary fibers. Although such fibers provide no energy or building materials, they play a vital role in our health. Found only in plants, dietary fiber is classified as soluble or insoluble. Soluble fiber, found in such foods as oats, barley, beans, peas, apples, strawberries, and citrus fruits, mixes with food in the stomach and prevents or reduces the absorption by the small intestine of potentially dangerous substances from food. Soluble fiber also binds dietary cholesterol and carries it out of the body, thus preventing it from entering the bloodstream where it can accumulate in the inner walls of arteries and set the stage for high blood pressure, heart disease, and strokes. Insoluble fiber, found in vegetables, whole-grain products, and bran, provides roughage that speeds the elimination of feces, which decreases the time that the body is exposed to harmful substances, possibly reducing the risk of colon cancer. Studies of populations with fiber-rich diets, such as Africans and Asians, show that these populations have less risk of colon cancer compared to those who eat low-fiber diets, such as Americans. In the United States, colon cancer is the third most common cancer for both men and women, but experts believe that, with a proper diet, it is one of the most preventable types of cancer.
Nutritionists caution that most Americans need to eat more complex carbohydrates. In the typical American diet, only 40 to 50 percent of total calories come from carbohydrates—a lower percentage than found in most of the world. To make matters worse, half of the carbohydrate calories consumed by the typical American come from processed foods filled with simple sugars. Experts recommend that these foods make up no more that 10 percent of our diet, because these foods offer no nutritional value. Foods rich in complex carbohydrates, which provide vitamins, minerals, some protein, and dietary fiber and are an abundant energy source, should make up roughly 50 percent of our daily calories.
Proteins
Protein, any of a large number of organic compounds that make up living organisms and are essential to their functioning. Dietary proteins are powerful compounds that build and repair body tissues, from hair and fingernails to muscles. In addition to maintaining the body’s structure, proteins speed up chemical reactions in the body, serve as chemical messengers, fight infection, and transport oxygen from the lungs to the body’s tissues. Although protein provides 4 calories of energy per gram, the body uses protein for energy only if carbohydrate and fat intake is insufficient. When tapped as an energy source, protein is diverted from the many critical functions it performs for our bodies.
Proteins are made of smaller units called amino acids. Of the more than 20 amino acids our bodies require, eight (nine in some older adults and young children) cannot be made by the body in sufficient quantities to maintain health. These amino acids are considered essential and must be obtained from food. When we eat food high in proteins, the digestive tract breaks this dietary protein into amino acids. Absorbed into the bloodstream and sent to the cells that need them, amino acids then recombine into the functional proteins our bodies need.
Protein molecules range from the long, insoluble fibers that make up connective tissue and hair to the compact, soluble globules that can pass through cell membranes and set off metabolic reactions. They are all large molecules, ranging in molecular weight from a few thousand to more than a million, and they are specific for each species and for each organ of each species. Humans have an estimated 30,000 different proteins, of which only about 2 percent have been adequately described. Proteins in the diet serve primarily to build and maintain cells, but their chemical breakdown also provides energy, yielding close to the same 4 calories per gram as do carbohydrates.
Animal proteins, found in such food as eggs, milk, meat, fish, and poultry, are considered complete proteins because they contain all of the essential amino acids our bodies need. Plant proteins, found in vegetables, grains, and beans, lack one or more of the essential amino acids. However, plant proteins can be combined in the diet to provide all of the essential amino acids. A good example is rice and beans. Each of these foods lacks one or more essential amino acids, but the amino acids missing in rice are found in the beans, and vice versa. So when eaten together, these foods provide a complete source of protein. Thus, people who do not eat animal products (see Vegetarianism) can meet their protein needs with diets rich in grains, dried peas and beans, rice, nuts, and tofu, a soybean product.
Experts recommend that protein intake make up only 10 percent of our daily calorie intake. Some people, especially in the United States and other developed countries, consume more protein than the body needs. Because extra amino acids cannot be stored for later use, the body destroys these amino acids and excretes their by-products. Alternatively, deficiencies in protein consumption, seen in the diets of people in some developing nations, may result in health problems. Marasmus and kwashiorkor, both life-threatening conditions, are the two most common forms of protein malnutrition.
Some health conditions, such as illness, stress, and pregnancy and breast-feeding in women, place an enormous demand on the body as it builds tissue or fights infection, and these conditions require an increase in protein consumption. For example, a healthy woman normally needs 45 grams of protein each day. Experts recommend that a pregnant woman consume 55 grams of protein per day, and that a breast-feeding mother consume 65 grams to maintain health.
A man of average size should eat 57 grams of protein daily. To support their rapid development, infants and young children require relatively more protein than do adults. A three-month-old infant requires about 13 grams of protein daily, and a four-year-old child requires about 22 grams. Once in adolescence, sex hormone differences cause boys to develop more muscle and bone than girls; as a result, the protein needs of adolescent boys are higher than those of girls.
These proteins, which come from the endocrine glands, do not act as enzymes. Instead they stimulate target organs that in turn initiate and control important activities—for example, the rate of metabolism and the production of digestive enzymes and milk. Insulin, secreted by the islands of Langerhans, regulates carbohydrate metabolism by controlling blood glucose levels. Thyroglobulin, from the thyroid gland, regulates overall metabolism; calcitonin, also from the thyroid, lowers blood calcium levels. Angiogenin, a protein structurally determined in the mid-1980s, directly induces the growth of blood vessels in tissues.
Besides their function in growth and cell maintenance, proteins are also responsible for muscle contraction. The digestive enzymes are proteins, as are insulin and most other hormones. The antibodies of the immune system are proteins, and proteins such as hemoglobin carry vital substances throughout the body.
Fats
Fats, which provide 9 calories of energy per gram, are the most concentrated of the energy-producing nutrients, so our bodies need only very small amounts. Fats play an important role in building the membranes that surround our cells and in helping blood to clot. Once digested and absorbed, fats help the body absorb certain vitamins. Fat stored in the body cushions vital organs and protects us from extreme cold and heat.
Fat consists of fatty acids attached to a substance called glycerol. Dietary fats are classified as saturated, monounsaturated, and polyunsaturated according to the structure of their fatty acids. Animal fats—from eggs, dairy products, and meats—are high in saturated fats and cholesterol, a chemical substance found in all animal fat. Vegetable fats—found, for example, in avocados, olives, some nuts, and certain vegetable oils—are rich in monounsaturated and polyunsaturated fat. As we will see, high intake of saturated fats can be unhealthy.
To understand the problem with eating too much saturated fat, we must examine its relationship to cholesterol. High levels of cholesterol in the blood have been linked to the development of heart disease, strokes, and other health problems. Despite its bad reputation, our bodies need cholesterol, which is used to build cell membranes, to protect nerve fibers, and to produce vitamin D and some hormones, chemical messengers that help coordinate the body’s functions. We just do not need cholesterol in our diet. The liver, and to a lesser extent the small intestine, manufacture all the cholesterol we require. When we eat cholesterol from foods that contain saturated fatty acids, we increase the level of a cholesterol-carrying substance in our blood that harms our health.
Cholesterol, like fat, is a lipid—an organic compound that is not soluble in water. In order to travel through blood, cholesterol therefore must be transported through the body in special carriers, called lipoproteins. High-density lipoproteins (HDLs) remove cholesterol from the walls of arteries, return it to the liver, and help the liver excrete it as bile, a liquid acid essential to fat digestion. For this reason, HDL is called “good” cholesterol.
Low-density lipoproteins (LDLs) and very-low-density lipoproteins (VLDLs) are considered “bad” cholesterol. Both LDLs and VLDLs transport cholesterol from the liver to the cells. As they work, LDLs and VLDLs leave plaque-forming cholesterol in the walls of the arteries, clogging the artery walls and setting the stage for heart disease. Almost 70 percent of the cholesterol in our bodies is carried by LDLs and VLDLs, and the remainder is transported by HDLs. For this reason, we need to consume dietary fats that increase our HDLs and decrease our LDL and VLDL levels.
Saturated fatty acids—found in foods ranging from beef to ice cream, to mozzarella cheese to doughnuts—should make up no more than 10 percent of a person’s total calorie intake each day. Saturated fats are considered harmful to the heart and blood vessels because they are thought to increase the level of LDLs and VLDLs and decrease the levels of HDLs.
Monounsaturated fats—found in olive, canola, and peanut oils—appear to have the best effect on blood cholesterol, decreasing the level of LDLs and VLDLs and increasing the level of HDLs. Polyunsaturated fats—found in margarine and sunflower, soybean, corn, and safflower oils—are considered more healthful than saturated fats. However, if consumed in excess (more than 10 percent of daily calories), they can decrease the blood levels of HDLs.
Most Americans obtain 15 to 50 percent of their daily calories from fats. Health experts consider diets with more than 30 percent of calories from fat to be unsafe, increasing the risk of heart disease. High-fat diets also contribute to obesity, which is linked to high blood pressure (see hypertension) and diabetes mellitus. A diet high in both saturated and unsaturated fats has also been associated with greater risk of developing cancers of the colon, prostate, breast, and uterus. Choosing a diet that is low in fat and cholesterol is critical to maintaining health and reducing the risk of life-threatening disease.
Psychological effect from fat hoard
Research focusing on heart disease and other circulatory disorders indicates that excessive consumption of foods high in fats, including lipids and sterols, increases the risk of developing these diseases. U.S. studies show that as much as 50 percent of the caloric intake in a modern diet consists of fats. Other studies demonstrate that the likelihood of heart disease decreases when the intake of saturated fats is reduced (see Artery; Heart: Heart Diseases; Nutrition, Human). Recent research indicates that excessive consumption of trans fats, such as those produced in the hydrogenation of vegetable oil to make margarine, may also increase the risk of heart disease.
When saturated solid fats are added to the diet, the amount of cholesterol in the blood increases, but when liquid, unsaturated fats or oils (particularly the polyunsaturated type) replace solid fat, the amount of cholesterol decreases. High cholesterol levels in the blood appear to promote the deposition of hard, fatty materials in the arteries, causing the arteries eventually to clog. When the coronary artery around the heart becomes clogged in this manner, blood supply to the heart is interrupted and a heart attack occurs. The American Heart Association recommends restricting the total fats in a diet, reducing the consumption of cholesterol-rich foods, such as milk and butter, replacing saturated fats with unsaturated fats, and limiting the intake of trans fats. Scientists are continuing to seek a thorough understanding of how the body handles fatty materials and why cholesterol levels rise to the point that fat is deposited on artery walls.
Vitamins and Minerals
Both vitamins and minerals are needed by the body in very small amounts to trigger the thousands of chemical reactions necessary to maintain good health. Many of these chemical reactions are linked, with one triggering another. If there is a missing or deficient vitamin or mineral—or link—anywhere in this chain, this process may break down, with potentially devastating health effects. Although similar in supporting critical functions in the human body, vitamins and minerals have key differences.
Among their many functions, vitamins enhance the body’s use of carbohydrates, proteins, and fats. They are critical in the formation of blood cells, hormones, nervous system chemicals known as neurotransmitters, and the genetic material deoxyribonucleic acid (DNA). Vitamins are classified into two groups: fat soluble and water soluble. Fat-soluble vitamins, which include vitamins A, D, E, and K, are usually absorbed with the help of foods that contain fat. Fat containing these vitamins is broken down by bile, a liquid released by the liver, and the body then absorbs the breakdown products and vitamins. Excess amounts of fat-soluble vitamins are stored in the body’s fat, liver, and kidneys. Because these vitamins can be stored in the body, they do not need to be consumed every day to meet the body’s needs.
Water-soluble vitamins, which include vitamins C (also known as ascorbic acid), B1 (thiamine), B2 (riboflavin), B3 (niacin), B6, B12, and folic acid, cannot be stored and rapidly leave the body in urine if taken in greater quantities than the body can use. Foods that contain water-soluble vitamins need to be eaten daily to replenish the body’s needs.
In addition to the roles noted in the vitamin and mineral chart accompanying this article, vitamins A (in the form of beta-carotene), C, and E function as antioxidants, which are vital in countering the potential harm of chemicals known as free radicals. If these chemicals remain unchecked they can make cells more vulnerable to cancer-causing substances. Free radicals can also transform chemicals in the body into cancer-causing agents. Environmental pollutants, such as cigarette smoke, are sources of free radicals.
Minerals are minute amounts of metallic elements that are vital for the healthy growth of teeth and bones. They also help in such cellular activity as enzyme action, muscle contraction, nerve reaction, and blood clotting. Mineral nutrients are classified as major elements (calcium, chlorine, magnesium, phosphorus, potassium, sodium, and sulfur) and trace elements (chromium, copper, fluoride, iodine, iron, selenium, and zinc).
Vitamins and minerals not only help the body perform its various functions, but also prevent the onset of many disorders. For example, vitamin C is important in maintaining our bones and teeth; scurvy, a disorder that attacks the gums, skin, and muscles, occurs in its absence. Diets lacking vitamin B1, which supports neuromuscular function, can result in beriberi, a disease characterized by mental confusion, muscle weakness, and inflammation of the heart. Adequate intake of folic acid by pregnant women is critical to avoid nervous system defects in the developing fetus. The mineral calcium plays a critical role in building and maintaining strong bones; without it, children develop weak bones and adults experience the progressive loss of bone mass known as osteoporosis, which increases their risk of bone fractures.
Vitamins and minerals are found in a wide variety of foods, but some foods are better sources of specific vitamins and minerals than others. For example, oranges contain large amounts of vitamin C and folic acid but very little of the other vitamins. Milk contains large amounts of calcium but no vitamin C. Sweet potatoes are rich in vitamin A, but white potatoes contain almost none of this vitamin. Because of these differences in vitamin and mineral content, it is wise to eat a wide variety of foods.
Too Little and too much food
When the body is not given enough of any one of the essential nutrients over a period of time, it becomes weak and less able to fight infection. The brain may become sluggish and react slowly. The body taps its stored fat for energy, and muscle is broken down to use for energy. Eventually the body withers away, the heart ceases to pump properly, and death occurs—the most extreme result of a dietary condition known as deficiency-related malnutrition.
Deficiency diseases result from inadequate intake of the major nutrients. These deficiencies can result from eating foods that lack critical vitamins and minerals, from a lack of variety of foods, or from simply not having enough food. Malnutrition can reflect conditions of poverty, war, famine, and disease. It can also result from eating disorders, such as anorexia nervosa and bulimia.
Although malnutrition is more commonly associated with dietary deficiencies, it also can develop in cases where people have enough food to eat, but they choose foods low in essential nutrients. This is the more common form of malnutrition in developed countries such as the United States. When poor food choices are made, a person may be getting an adequate, or excessive, amount of calories each day, yet still be undernourished. For example, iron deficiency is a common health problem among women and young children in the United States, and low intake of calcium is directly related to poor quality bones and increased fracture risk, especially in the elderly.
A diet of excesses may also lead to other nutritional problems. Obesity is the condition of having too much body fat. It has been linked to life-threatening diseases including diabetes mellitus, heart problems, and some forms of cancer. Eating too many salty foods may contribute to high blood pressure (see hypertension), an often undiagnosed condition that causes the heart to work too hard and puts strain on the arteries. High blood pressure can lead to strokes, heart attacks, and kidney failure. A diet high in cholesterol and fat, particularly saturated fat, is the primary cause of atherosclerosis, which results when fat and cholesterol deposits build up in the arteries, causing a reduction in blood flow.
Making good nutritional choice
To determine healthful nutrition standards, the Food and Nutrition Board of the National Academy of Sciences (NAS), a nonprofit, scholarly society that advises the United States government, periodically assembles committees of national experts to update and assess nutrition guidelines. The NAS first published its Recommended Dietary Allowances (RDAs) in 1941. An RDA reflects the amount of a nutrient in the diet that should decrease the risk of chronic disease for most healthy individuals. The NAS originally developed the RDAs to ensure that World War II soldiers stationed around the world received enough of the right kinds of foods to maintain their health. The NAS periodically has updated the RDAs to reflect new knowledge of nutrient needs.
In the late 1990s the NAS decided that the RDAs, originally developed to prevent nutrient deficiencies, needed to serve instead as a guide for optimizing health. Consequently, the NAS created Dietary Reference Intakes (DRIs), which incorporate the RDAs and a variety of new dietary guidelines. As part of this change, the NAS replaced some RDAs with another measure, called Adequate Intake (AI). Although the AI recommendations are often the same as those in the original RDA, use of this term reflects that there is not enough scientific evidence to set a standard for the nutrient. Calcium, which has an AI of 1,000 to 1,300 mg per day, is not an RDA because scientists do not yet know how much calcium is needed to prevent osteoporosis.
Tolerable Upper Intake Level (UL) designates the highest recommended intake of a nutrient for good health. If intake exceeds this amount, health problems may develop. Calcium, for instance, has a UL of 2500 mg per day. Scientists know that more than this amount of calcium taken every day can interfere with the absorption of iron, zinc, and magnesium and may result in kidney stones or kidney failure.
Estimated Average Requirement (EAR) reflects the amount of a particular nutrient that meets the optimal needs of half the individuals in a specified group. For example, the NAS cites an EAR of 45 to 90 grams of protein for men aged 18 to 25. This figure means that half the men in that population need a daily intake of protein that falls within that range.
To simplify the complex standards established by the NAS, the United States Department of Agriculture (USDA) created the Food Guide Pyramid, a visual display of the relative importance to health of six food groups common to the American diet. The pyramid recommends a range of the number of servings to choose from each group, based on the nutritional needs of males and females and different age groups. In 2005 the pyramid was updated to accommodate different levels of physical exercise and caloric intake resulting in 12 unique pyramids tailored to fit individual needs.
In an effort to provide additional nutritional guidance and reduce the incidence of diet-related cancers, the National Cancer Institute developed the 5-a-Day Campaign for Better Health, a program that promotes the practice of eating five to nine servings of fruits and vegetables daily. Studies of populations that eat many fruits and vegetables reveal a decreased incidence of diet-related cancers. Laboratory studies have shown that many fruits and vegetables contain phytochemicals, substances that appear to limit the growth of cancer cells.
Many people obtain most of their nutrition information from a food label called the Nutrition Facts panel. This label is mandatory for most foods that contain more than one ingredient, and these foods are mostly processed foods. Labeling remains voluntary for raw meats, fresh fruits and vegetables, foods produced by small businesses, and those sold in restaurants, food stands, and local bakeries.
The Nutrition Facts panel highlights a product’s content of fat, saturated fat, cholesterol, sodium, dietary fiber, vitamins A and C, and the minerals calcium and iron. The stated content of these nutrients must be based on a standard serving size, as defined by the Food and Drug Administration (FDA). Food manufacturers may provide information about other nutrients if they choose. However, if a nutritional claim is made on a product’s package, the appropriate nutrient content must be listed. For example, if the package says “high in folic acid,” then the folic acid content in the product must be given in the Nutrition Facts panel.
The Nutrition Facts panel also includes important information in a column headed % Daily Value (DV). DVs tell how the food item meets the recommended daily intakes of fat, saturated fat, cholesterol, carbohydrates, dietary fiber, and protein necessary for nutritional health based on the total intake recommended for a person consuming 2,000 calories per day. One portion from a can of soup, for example, may have less than 2 percent of the recommended daily value for cholesterol intake.
Health-conscious consumers can use the Nutrition Facts panel to guide their food choices. For example, based on a daily diet of 2,000 calories, nutrition experts recommend that no more than 30 percent of those calories should be from fat, which would allow for a daily intake of around 65 grams of fat. A Nutrition Facts panel may indicate that a serving of one brand of macaroni and cheese contains 14 grams of fat, or a % DV of 25 percent. This tells the consumer that a serving of macaroni and cheese provides about one-fourth of the suggested healthy level of daily fat intake. If another brand of macaroni and cheese displays a % DRV of 10 percent fat, the nutrition-conscious consumer would opt for this brand.
Nutritionists and other health experts help consumers make good food choices. People who study nutrition in college may refer to themselves as nutritionists; often, however, the term refers to a scientist who has pursued graduate education in this field. A nutritionist may also be a dietitian. Dietitians are trained in nutrition, food chemistry, and diet planning. In the United States, dietitians typically have graduated from a college program accredited by the American Dietetic Association (ADA), completed an approved program of clinical experience, and passed the ADA’s registration examination to earn the title Registered Dietitian (RD).
Antidepressant
Antidepressant, medication used to treat depression, a mood disorder characterized by such symptoms as sadness, decreased appetite, difficulty sleeping, fatigue, and a lack of enjoyment of activities previously found pleasurable. While everyone experiences episodes of sadness at some point in their lives, depression is distinguished from this sadness when symptoms are present most days for a period of at least two weeks. Antidepressants are often the first choice of treatment for depression.
Although the cause of depression is unknown, researchers have found that some depressed people have altered levels of chemicals called neurotransmitters, chemicals made and released by nerve cells, or neurons. One neuron, referred to as the presynaptic neuron, releases a neurotransmitter into the synapse, or space, between the neuron and a neighboring cell. The neurotransmitter then attaches, or binds, to a neighboring cell—the postsynaptic cell—to trigger a specific activity. Antidepressants work by interacting with neurotransmitters at three different points: they can change the rate at which the neurotransmitters are either created or broken down by the body; they can block the process in which a spent neurotransmitter is recycled by a presynaptic neuron and used again, called reuptake; or they can interfere with the binding of a neurotransmitter to neighboring cells.
All antidepressants decrease symptoms of depression in about 70 percent of depressed people who take them. Most antidepressants take about two to three weeks of treatment before beneficial effects occur. Because no antidepressant is more effective than the others, doctors determine which antidepressant to prescribe according to the type of side effects an individual can tolerate. For instance, a person who takes TCAs and MAO inhibitors may notice dizziness and fainting when standing up, mouth dryness, difficulty urinating, constipation, and drowsiness. If people who take MAO inhibitors eat certain foods, such as aged cheese or some aged meats, they can experience severe headaches and raised blood pressure. SSRIs can cause side effects such as restlessness, difficulty sleeping, and interference with sexual function.
