As you grow older, if you continue eating the same types and amounts of food but do not become more active, you will probably gain weight. That's because your metabolism (how your body gets energy from food) slows with age. Your body uses less energy, and that means it needs less food to make the energy it needs. The energy your body gets from the nutrients in the food you eat is measured as calories.
You may have heard the phrase "calories in, calories out" or maybe "energy in, energy out." It's true—as a rule of thumb, the more calories you eat, the more active you have to be. Likewise, the reverse is also true--the more active you are, the more calories you need. If you eat more calories than your body uses, you could gain weight. As you age, your body might need less food for energy, but it still needs the same amount of the nutrients we just described. What should you do?
What's On Your Plate? is based on the nutrition recommendations for older adults in the Dietary Guidelines for Americans, 2010  from the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services (HHS).