what are the daily requirements of carbohydrates, proteins and fats in a normal adult person
Answers
Explanation:
Carbohydrates, Proteins, and Fats
By Adrienne Youdim, MD, David Geffen School of Medicine at UCLA
Last full review/revision Aug 2019| Content last modified Aug 2019
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Carbohydrates, proteins, and fats supply 90% of the dry weight of the diet and 100% of its energy. All three provide energy (measured in calories), but the amount of energy in 1 gram (1/28 ounce) differs:
4 calories in a gram of carbohydrate or protein
9 calories in a gram of fat
These nutrients also differ in how quickly they supply energy. Carbohydrates are the quickest, and fats are the slowest.
Carbohydrates, proteins, and fats are digested in the intestine, where they are broken down into their basic units:
Carbohydrates into sugars
Proteins into amino acids
Fats into fatty acids and glycerol
The body uses these basic units to build substances it needs for growth, maintenance, and activity (including other carbohydrates, proteins, and fats).
Carbohydrates
Depending on the size of the molecule, carbohydrates may be simple or complex.
Simple carbohydrates: Various forms of sugar, such as glucose and sucrose (table sugar), are simple carbohydrates. They are small molecules, so they can be broken down and absorbed by the body quickly and are the quickest source of energy. They quickly increase the level of blood glucose (blood sugar). Fruits, dairy products, honey, and maple syrup contain large amounts of simple carbohydrates, which provide the sweet taste in most candies and cakes.
Complex carbohydrates: These carbohydrates are composed of long strings of simple carbohydrates. Because complex carbohydrates are larger molecules than simple carbohydrates, they must be broken down into simple carbohydrates before they can be absorbed. Thus, they tend to provide energy to the body more slowly than simple carbohydrates but still more quickly than protein or fat. Because they are digested more slowly than simple carbohydrates, they are less likely to be converted to fat. They also increase blood sugar levels more slowly and to lower levels than simple carbohydrates but for a longer time. Complex carbohydrates include starches and fibers, which occur in wheat products (such as breads and pastas), other grains (such as rye and corn), beans, and root vegetables (such as potatoes and sweet potatoes).
Carbohydrates may be
Refined
Unrefined
Refined means that the food is highly processed. The fiber and bran, as well as many of the vitamins and minerals they contain, have been stripped away. Thus, the body processes these carbohydrates quickly, and they provide little nutrition although they contain about the same number of calories. Refined products are often enriched, meaning vitamins and minerals have been added back to increase their nutritional value. A diet high in simple or refined carbohydrates tends to increase the risk of obesity and diabetes.
If people consume more carbohydrates than they need at the time, the body stores some of these carbohydrates within cells (as glycogen) and converts the rest to fat. Glycogen is a complex carbohydrate that the body can easily and rapidly convert to energy. Glycogen is stored in the liver and the muscles. Muscles use glycogen for energy during periods of intense exercise. The amount of carbohydrates stored as glycogen can provide almost a day’s worth of calories. A few other body tissues store carbohydrates as complex carbohydrates that cannot be used to provide energy.
Most authorities recommend that about 50 to 55% of total daily calories should consist of carbohydrates. Fewer than 10% of total daily calories should come from added sugars. Added sugars are syrups and other caloric sweeteners used in other food products. Added sugars are listed as an ingredient in food labels. They include brown sugar, corn sweetener, corn syrup, dextrose, fructose, glucose, high-fructose corn syrup, honey, invert sugar, lactose, malt syrup, maltose, molasses, raw sugar, sucrose, trehalose, and turbinado sugar. Naturally occurring sugars, such as those in fruit or milk, are not added sugars