Protein is core to building muscle and, even more so, maintaining it, Klingbeil says. The National Academy of Sciences recommends that adults eat 0.36 gram of protein per pound of body weight per day. But an analysis of data from the National Health and Nutrition Examination Survey found that 42 percent of men and 50 percent of women over age 70 don’t get that much.
Some experts recommend even more protein for older adults to compensate for muscle loss and the fact that building new muscle becomes harder with age, Klingbeil says. Aim for 0.45 to 0.59 gram per pound per day—that’s 72 to 94 grams for a 160-pound person. (But if you have kidney disease, check with your doctor about your protein intake because too much can tax your kidneys.) Dietitians generally recommend spreading protein throughout the day because that may help your body absorb it better, but Klingbeil says that getting enough is the most important thing.
The source of protein isn’t super-important for building muscle, says Travis Masterson, PhD, the Broadhurst Career Development Professor for the Study of Health Promotion and Disease Prevention at Pennsylvania State University in University Park. Animal foods tend to have more per serving than plant sources. But for other aspects of your health, it’s best to get at least some of your protein from plants, such as beans, nuts, and tofu.
A plant-based diet that includes mostly whole foods is good for your heart and brain, and it lowers your risk of certain cancers. “It also appears to be gentler on the kidneys than a diet high in animal protein as we age,” says Judy Lester, MS, a clinical dietitian at the University of North Carolina Health Care System in Chapel Hill.
There are 20 grams of protein in a cup of tofu; about 18 grams in a cup of lentils, white beans, or edamame; 8 grams in a cup of quinoa or whole-wheat pasta; and 7 grams in an ounce of peanuts. Beef, salmon, and chicken breast have about 24 grams in 3 ounces. A 5.5-ounce serving of plain nonfat Greek yogurt has 16 grams, a cup of low-fat milk has about 9 grams, and an egg has 6 grams.
