A person's caloric requirement depends on his 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.
Getting enough water also is important. Many experts recommend at least eight 8-ounce glasses of water daily—more if you exercise frequently or are exposed to extremes of heat and cold. The 2010 Dietary Guidelines for Americans emphasize drinking more water and other calorie-free beverages, along with fat-free or low-fat milk and 100 percent fruit juices, instead of calorie-packed regular sodas.
What's a man to do? Fortunately, he does not have to choose between his bones and his prostate. The solution is moderation. The Baltimore Longitudinal Study of Aging, for example, found no link between a moderate consumption of calcium (about 800 mg a day, two-thirds of the RDA) and prostate cancer. In addition, a randomized clinical trial of calcium supplements of 1,200 mg a day found no effect on the prostate, but only 327 men were in the calcium group, and the supplementation lasted just four years. Finally, the Harvard scientists speculate that a high consumption of vitamin D may offset the possible risks of calcium, so a daily multivitamin may also help.
A 55-year-old woman who gets less than 30 minutes of daily physical activity should eat five ounces of grains; two cups of vegetables; one and a half cups of fruit; three cups of milk; five ounces of meat and beans; five teaspoons of oils, and no more than 130 calories of additional fat and sugar. If she got 30 to 60 minutes of daily exercise, she could increase her intake to six ounces of grains; two and a half cups of vegetables; and up to 265 additional calories of fat and sugar.
In the past, women have often tried to make up deficits in their diet though the use of vitamins and supplements. However, while supplements can be a useful safeguard against occasional nutrient shortfalls, they can’t compensate for an unbalanced or unhealthy diet. To ensure you get all the nutrients you need from the food you eat, try to aim for a diet rich in fruit, vegetables, quality protein, healthy fats, and low in processed, fried, and sugary foods.