The ways in which men and women differ are innumerable. Now you can add nutritional needs to the list.
While women would seem to have more special nutritional needs than men, given the demands that biology puts on them, men need to pay attention to their own set of nutritional demands as well.
Many problems caused in part by nutrition are common to both men and women, such as cardiac disease, obesity, and diabetes. In general, absolute nutritional requirements in men are greater than in women, simply because men as a population are larger and have more muscle mass than women.
"[Men's] calorie needs are greater," says David Heber, MD, director of the UCLA Center for Human Nutrition in Los Angeles. "Those needs are dependent on the amount of lean body mass and average about 14 calories per pound of lean body mass per day at rest with additional calories for exercise."
For example, Heber added, a typical 180-pound man who has 17% body fat would have 150 pounds of lean muscle and would need 2,100 calories per day at rest. A woman who weighs 130 pounds with 100 pounds of lean body mass at about 23% body fat would need 1,400 calories at rest.
"You might add 300 to 500 calories per day for physical activity," Heber notes. "However, the differences are quite large, as you can see."
In large part, these differences are driven by reproductive hormones, Heber says. In men, testosterone is responsible for muscle mass differences from women and this hormone accounts for the extra muscle driving extra protein and calorie requirements.
But there are subtler differences, also.
"Even if you take differences in size and weight out of the equation and express nutritional needs per body weight or lean body mass, there are still differences between men and women," says Paul J. Flakoll, PhD, professor of nutritional physiology and director of the Center for Designing Foods to Improve Nutrition at Iowa State University in Ames, Iowa. "Obviously, there are differences during life events specifically related to women, such as pregnancy and lactation, which men do not experience."
Normal levels of circulating red blood cells are higher in men than in women, which may have nutritional implications, Flakoll says, adding that men do not tolerate low levels of plasma glucose, or hypoglycemia, as well as women.
Men and women need good sources of protein in their diets. However, men's protein needs may be proportionally greater, especially if a man is physically active.
To build muscle mass, men might want to increase their protein levels above the regular daily requirements, according to Rachel Agnew, RD, and Sandra P. Marin, MPH, RD, who are members of the professional education team at the Nature Made company, a manufacturer of nutritional supplements based in Mission Hills, Calif.
Agnew and Marin say that to determine your optimal protein needs, divide your weight in pounds by 2.2. The ending figure is a good upper figure for the amount of protein you need. For example, they say, a 32-year-old man who weighs 180 pounds who wanted to increase lean muscle mass should eat up to 82 grams (his weight in kilograms) daily.
"We have this idea that it's easy to get too much protein, but really men who are active and want to maintain muscle mass need to eat more protein than they might think they need," say Philip Goglia, PhD, a nutritionist and founder of Performance Fitness Concepts, a testing center for sports training in Venice, Calif.
"Too often we turn to carbohydrate-heavy meals in the evening. Carbohydrates are satisfying and taste good, but men are better off eating the majority of their protein at dinner, which helps their bodies rebuild muscle tissues overnight," adds Goglia, who also is the author of Turn Up The Heat, Unlock the Fat Burning Power of Your Metabolism.
Age Affects Men's Nutrition
"Metabolic rates decrease as age increases, and physical activity also decreases with aging, thus, energy needs tend to be reduced with aging," says Flakoll. "However, good quality protein and vitamin and mineral needs continue to be very important."
It is important for diets to be more nutrient dense as men age, Flakoll notes. Quality nutrients are important to maintain men's immune function and overall health, as well as preventing bone loss, eyesight loss, and muscle loss, he says, adding that "prevention of oxidative damage and maintenance of tissue health via antioxidative vitamins and minerals become more important as men age."
Agnew and Marin agree, saying, as we age, lean muscle mass is gradually replaced by fat. As the body composition shifts towards more body fat, calorie requirements decline. That's why if you keep your same eating pattern in your 40s as you did in your 20s, you will most likely gain weight.
They added that exercise must be part of the regimen to help maintain lean muscle mass. Part of the reason we may see less lean muscle mass among older men, may be because there is also a decrease in the number of men who do weight training as they age. Exercise can help maintain muscle mass and help maintain a "fast" metabolism as we age.
And although there are many supplements out there that promise to help men as they age, Heber says he's seen little convincing evidence.
"The benefits of hormone or pre-hormone supplements has not been proven in the literature," he says. "Certainly, it may seem to make sense to use these types of hormones to make up for deficits as men age. However, publications of good clinical trials that provide valid assessments of risks and benefits are lacking in peer-reviewed journals."
Calcium Is Vital
Calcium is as important for men as it is for women, according to Agnew and Marin. They say that men's need for calcium is one "often-overlooked similarity between men's and women's nutritional needs." Osteoporosis tends to be looked at as a "woman's disease," but this is not always the case. In fact, they say, "one in four men over age 50 will have an osteoporosis-related fracture in his lifetime."