Good nutrition: Should guidelines differ for men and women?

In the stereotypical Ozzie and Harriet family of the 1950s, men ruled the roost while women ruled the roast. That’s no longer true (if it ever was). But when it comes to optimal nutrition, there are differences between the sexes. And while they’re subtle, they may affect your health.

Here are a few similarities and differences in dietary guidelines for men and women.

Calories

Men and women are 98.5% identical in their DNA, and their nutritional needs are more similar than different. That’s certainly true of calories; in this case, at least, men act just like big women.

A person’s caloric requirement depends on his or her body size and exercise level. Sedentary people of both genders will keep their weight stable by taking in about 13 calories per pound of body weight each day. Moderate physical activity boosts this requirement to 16 calories a pound, and vigorous exercise calls for about 18 calories a pound. On average, a moderately active 125-pound woman needs 2,000 calories a day; a 175-pound guy with a similar exercise pattern needs 2,800 calories. And like women, men will lose weight only if they burn more calories than they take in.

Protein

Here, too, body size is the main difference between the needs of males and females. Despite all the hype about high-protein diets, our protein requirements are really quite modest — only about a third of a gram per pound of body weight. For a 125-pound woman, that amounts to about 42 grams; for a 175-pound man, 58 grams. That’s a tiny difference, just about half an ounce a day.

Protein should provide about 15% of a healthy person’s daily calories. As a rule of thumb, people of both sexes and any size will do fine with about 60 grams of protein a day. Athletes who have large muscles and work out hard may need 20% more. But even that’s not very much; 8 ounces of chicken or 6 ounces of canned tuna, for example, will fit the bill.

Most Americans get far more protein than they really need. In theory, that may not be wise. Like carbohydrates, protein provides 4 calories per gram, and excess calories from any source will be stored as body fat. Excess dietary protein increases calcium loss in the urine, perhaps raising the risk for osteoporosis (“thin bones,” more a worry for women) and kidney stones (a particular worry for men).

Carbohydrates

Carbs are gender-neutral. But that doesn’t mean you should be neutral about the carbohydrates you eat.

Carbohydrates should provide 45% to 65% of your daily calories. Most of those calories should come from the complex carbohydrates in high-fiber and unrefined foods, such as bran cereal and other whole-grain products, brown rice, beans and other legumes, and many fruits and vegetables.

These carbohydrates are digested and absorbed slowly, so they raise the blood sugar gradually and don’t trigger a large release of insulin. People who eat lots of these foods have higher HDL (“good”) cholesterol levels and a lower risk of obesity, diabetes, and heart disease. A good amount of soluble fiber in the diet lowers LDL (“bad”) cholesterol, and high-fiber diets reduce the risk of intestinal disorders ranging from constipation and diverticulosis to hemorrhoids. Men need more fiber than women: 38 vs. 25 grams a day before the age of 50 and 30 vs. 21 grams a day thereafter.

Simple sugars are another matter; they really are empty calories. You should limit your sugar consumption to 10% of your daily calories; for the average person, that’s about 60 grams or 12 teaspoons of table sugar.

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