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).
“The reason most people don't see changes isn't because they don't work hard—it's because they don't make their workouts harder,” says Adam Bornstein, founder of Born Fitness. His suggestion: Create a challenge every time you exercise. “Use a little more weight, rest five to 10 seconds less between sets, add a few more reps, or do another set. Incorporating these small variations into your routine is a recipe for change,” he says.
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.
Popular belief says if you really want to make a big change, focus on one new healthy habit at a time. But Stanford University School of Medicine researchers say working on your diet and fitness simultaneously may put the odds of reaching both goals more in your favor. They followed four groups of people: The first zoned in on their diets before adding exercise months later, the second did the opposite, the third focused on both at once, and the last made no changes. Those who doubled up were most likely to work out 150 minutes a week and get up to nine servings of fruits and veggies daily while keeping their calories from saturated fat at 10 percent or less of their total intake.
The daily calcium recommendations are 1,000 milligrams a day for women under 50, and 1,500 milligrams a day for women 51 and older. Oddly enough, these are the same requirements for men, who are much less prone to osteoporosis than women. But the recommendation takes into account the fact that women are smaller than men. Thus the amount of daily calcium is greater for women on a proportional basis.
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.