Is there a best diet for healthy aging, living longer? No, but there are some important basics.

Worldwide, people are living longer. In 2000, one in 10 people in the United States was 65 or older. By 2035, the United Nations predicts one in five will be 65 or older — with over 6% of the U.S. population over 80.

Numerous studies show that what we eat can affect health and longevity, so what’s the best diet for aging and living a longer, healthier life?

“There’s no best diet, but there are a lot of good ones,” says Christine Rosenbloom, a nutrition professor emerita at Georgia State University and co-author of “Food and Fitness after 50.”

Rosenbloom says a healthy eating plan is flexible, includes foods people like and addresses an individual’s health concerns. But, in today’s anti-aging culture with headlines and chatter about popular diet trends, how does one determine what makes up a good diet?

Here are some red flags to consider to help determine what’s reliable information when it comes to today’s (or tomorrow’s) fad diet:

• Nutrient deficiency or excess. Eating plans that limit or restrict foods or food groups make it difficult to get the nutrients needed for healthy aging. For example, eliminating whole grains, beans, legumes or fruit decreases fiber necessary for maintaining intestinal health and protecting against heart disease. Food plans that restrict dairy foods make it harder to meet calcium, vitamin D and phosphorus needs. Very low-carbohydrate diets can lead to excessive fat intake, potentially increasing the risk of heart disease and certain cancers.
• Poor energy. Diets that encourage skipping meals or restricting carbohydrates can deplete the body’s fuel sources, resulting in fatigue. Because glucose is the main energy source for the brain, lack of focus or concentration can increase an older adult’s risk of falls or, for physically active individuals, an increased risk of injury to muscle or bone tissue.
• Loss of lean tissue and weight regain. Caloric restriction for weight control — most diets — can lead to a loss of lean tissue. So, when the dieter stops the diet or resumes past eating patterns, the body restores weight — often in the form of fat. Recent studies have documented the negative effects of repeated cycles of dieting.
• Increased risk of disordered eating. The pursuit of weight loss, even in the name of health, can contribute to emotional and psychological distress and can contribute to mood disorders or depression when the dieter is unable to achieve expected weight goals or regains the lost weight.

Principles that support healthy eating for older adults include:

• Eat a balanced diet. As people age, calorie needs decrease. But many nutrient needs remain high. Some older people struggle with loss of appetite, taste changes, teeth or denture issues, side effects from medication, budget concerns or dependence on institutional meals and might be eating less food or less variety.

To maximize nutrient-dense foods, Rosenbloom encourages older adults to stock up on pantry basics, including canned beans and vegetables. She tries to dispel the myth that only fresh fruits and vegetables are healthy. Packaged foods can be healthy, are easier to prepare and have a longer shelf life.

• Improve diet quality. A diet high in plant foods — beans, vegetables, nuts, fruit, whole grains — and low in processed foods is associated with improvements in cardiovascular health measures and is recommended by the American Institute for Cancer Research for reducing cancer risk.

For people who want to adopt a plant-based diet but don’t want to give up meat, Rosenbloom recommends a Mediterranean diet that encourages eating more fish and less red meat or the DASH diet — Dietary Approaches to Stop Hypertension.

Both diets emphasize vegetables and fruits, low-fat dairy foods, moderate amounts of whole grains, fish, poultry and nuts, and they have high-quality studies showing positive health outcomes.

• Create a support circle. An observation from the diet literature is that people are successful when they have accountability and support. So try to choose one or two people who will help you be successful with your goals. Schedule fitness- and nutrition-oriented gatherings to connect, share recipes and learn how to prepare healthy meals.
• Start small. Change should come gradually in order to sustain behavior modification. For example, add fish or a meatless meal to the menu once a week, or add one serving of fruit and vegetables a day.

“Regarding sweets and desserts, I remind people the second half tastes like the first,” Rosenbloom says. “Keep a watch on the portions, and enjoy your food.”

Environmental Nutrition is an independent newsletter written by experts on health and nutrition.