The U.S. population is aging. The majority of residents are middle-aged or older (older than 45 years), and the ratio of older people to young is increasing.

The fastest growing age group is the older than 85 sector. Since 1950, their numbers have increased sevenfold.

Life expectancy in the U.S. also has risen – to 81 years for white women, 76 years for black women, 75 years for white men and 69 years for black men. In 1900, life expectancy was a mere 47 years for most people.

Good nutrition has long been associated with longevity, but the questions still being asked are “what role does nutrition play in the aging process, and what role can it play in slowing aging?” Aging is an inevitable and natural process, but it can be slowed (within genetic limits; the oldest age it is thought humans could possibly live is 130 years) by healthy lifestyle behaviors and good nutrition throughout life. Good nutrition can also improve our quality of life, especially as we age.

One of the most important outcomes of eating a healthy diet affects us more as we age – weight gain. Keeping a healthy weight throughout your adult life will improve your chances of living longer and lower your risks for most types of chronic disease, such as cancer, heart disease, high blood pressure, diabetes, stroke and arthritis. As we age, most people gain weight slowly, maybe 5 pounds per decade, but this creeping weight gain affects our health and quality of life. Two-thirds of adults in the U.S. are overweight or obese, and the older we get, the more we tend to lose bone and muscle and gain body fat. Hormones that regulate appetite and metabolism decrease and become less active with age, so it’s more important to eat healthy and decrease the amount of calories eaten the older we get.

Calorie needs generally diminish 5 percent per decade, although staying physically active could help lower that percentage. Our basal metabolic rate (how many calories we need to keep our organs and brain functioning) decreases 1 to 2 percent per decade because all of us tend to lose muscle as we age and thyroid hormones diminish. Estimated calorie requirements decrease steadily after age 19. Because of reduced muscle mass, protein requirements decrease as we age, so we need to eat low-calorie sources of high-quality protein, such as lean meats, poultry, fish, eggs, low-fat dairy and legumes.

Carbohydrates are needed to keep the body from burning protein as fuel, which can make the body toxic (a state called ketosis, which can be deadly). Complex carbs such as whole grains, fruits, vegetables and legumes are recommended, staying away from refined carbs such as cakes, cookies, doughnuts, white bread and anything made with refined grains. Limit fat intake to decrease calories, making sure to get enough to utilize the fat-soluble vitamins and other nutrients (this is equal to 2 teaspoons per day of fat, which most of us have no problem getting).

Staying healthy as we age starts with healthy eating when we’re younger. It’s never too early (or too late) to start.

Jeanine Justice has 20 years of experience in nutrition. She is currently the coordinator for Healthy Lifestyle La Plata Coalition. Reach her at jeanine@swcommunity foundation.org.

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The best way to ensure healthy aging is to eat a balanced diet throughout your life full of fruits, vegetables, whole grains, limited amounts of lean meat and protein, low or nonfat dairy products, moderate or no alcohol, and continue to be physically active.

Vitamin B12 (2.4 micrograms, which is best to get from fortified foods or supplements as food sources are harder to absorb) is needed as our bodies can’t absorb it as well as we age, and vitamin D is needed in greater amounts as our bodies don’t make as much the older we get. The newest recommendations are 600 IUs up to 70 years old, and 800 IUs 70 years and older.