Читать книгу Nutrition For Dummies - Carol Ann Rinzler - Страница 15

Sugar and spice and everything nice well, more precisely water and fat and protein and carbohydrates (the simple and complex sugars described in Chapter 8) and vitamins and minerals.

On average, when you step on the scale, approximately 60 percent of your weight is water, 20 percent is body fat (slightly less for a man), and 20 percent is a combination of mostly protein, plus carbohydrates, minerals, vitamins, and other naturally occurring biochemicals.

Based on these percentages, you can reasonably expect that an average 140-pound person’s body weight consists of about

 84 pounds of water

 28 pounds of body fat

 28 pounds of a combination of protein (up to 25 pounds), minerals (up to 7 pounds), carbohydrates (up to 1.4 pounds), and vitamins (a trace)

You’re right: Those last figures do total more than 28 pounds. That’s because “up to” (as in “up to 25 pounds of protein”) means that the amounts may vary from person to person. Ditto for minerals and carbohydrates.

Why? And how? Because a young person’s body has proportionately more muscle and less fat than an older person’s, and a woman’s body has proportionately less muscle and more fat than a man’s. As a result, more of a man’s weight comes from protein and muscle and bone mass, while more of a woman’s weight comes from fat. Protein-packed muscles and mineral-packed bones are denser tissue than fat.

Weigh a man and a woman of roughly the same height and size, and his greater bone and muscle mass means he’s likely to tip the scale higher every time.

Here are three other examples of nutrients that are essential for some pets and plants but not necessarily for humans:

 Myo-inositol: Myo-inositol, an organic compound similar to glucose — the fuel we get from carbohydrates — is an essential nutrient for gerbils and rats who can’t make it in their own bodies and thus must get what they need from food. It’s nonessential for human beings who can synthesize myo-inositol and then use it in dozens of important body processes, such as transmitting signals between cells.

 Taurine: The amino acid taurine is essential for cats, but conditionally essential for humans, which means essential for some people but not all. All human bodies except newborns synthesize taurine from the amino acids methionine and cysteine (see Chapter 6), so although adults can make their own taurine, newborns need to get theirs from food, either breast milk or formula. That’s why its essential nature is conditional.

 Boron: Several minerals, such as boron, are essential for plants but haven’t been proven essential for either microorganisms, such as bacteria, or for animals, including people.

For more on the vitamins and minerals, amino acids (the so-called building blocks of proteins), and fatty acids that are considered essential for your human body, check out Chapters 6, 7, 10, and 11.