What’s a body made of?

Sugar and spice and everything nice . . . Oops. What I meant to say was the human body is made of water and fat and protein and carbohydrates 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).

Yep, 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. For example, a young person’s body has proportionately more muscle and less fat than an older person’s, while 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 calcium, while more of a woman’s body 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 he’s likely to tip the scale higher every time.
The National Research Council, Recommended Dietary Allowances (Washington D.C.: National Academy Press, 1989); Eleanor Noss Whitney, Corinne Balog Cataldo, and Sharon Rady Rolfes, Understanding Normal and Clinical Nutrition (Minneapolis/St. Paul: West Publishing Company, 1994)