Your 60s can present major changes, like adjusting to or preparing for retirement or a new lifestyle. According to recent evidence, this is also the decade when your metabolism begins to change—and perhaps, so should your diet.

Around age 60, you require fewer calories to function—but your nutrient and protein needs stay the same or possibly increase. This means in order to maintain your weight and keep your lab measurements in range, you may need to downsize your meal portions while prioritizing protein, says Nathan Razbannia, MD, MPH, a Cedars-Sinai family medicine doctor in Marina del Rey.

This doesn’t mean you should wait to age into healthy habits: It’s never too early (or too late) to commit to a balanced diet. Establishing a baseline earlier in life will help you maintain weight and muscle mass, which can be critical to avoiding frailty and preserving resilience when you’re older.

“No matter your age, if you haven’t been incorporating chicken, fish, fruits and vegetables, you’re not getting the right nutrients,” Razbannia said. “Getting the right balance early on can help prevent chronic disease later.”

Here, Razbannia and Daniel Stone, MD, a Cedars-Sinai internal medicine doctor in Beverly Hills, outline how to shift to a healthy diet to help keep yourself well now—and for as long as possible.

Read: The Future of Aging Research

The aging process is complex, nuanced and variable to a person. But everyone experiences a physiological fact: In your 60s, your body’s metabolic requirements decrease, and you need fewer calories in your diet. For younger people with chronic disease, this change could begin earlier.

"It’s a fact of life," Razbannia said. "Your muscle mass decreases, and your body fat increases."

As you age, your previous dietary habits might not suffice to maintain a healthy weight, even if they did before. Though body mass index (BMI) doesn’t reflect muscle-to-fat ratio, it can be an appropriate measurement—alongside other levels like cholesterol, blood sugar and blood pressure—to indicate whether you should tweak your diet, Stone said.

At the same time, aging impacts the body’s ability to absorb nutrients like vitamin B12. These nutrient deficiencies can be avoided with a basic, healthy diet.

When it’s time to make a change, start by replacing processed foods with protein and vegetables. Initially, you can set a goal of eating enough protein, rather than reducing portion size or counting calories.

“Integrate healthy habits, rather than stressing about exact measurements,” Stone said.

If you’ve relied on takeout or packaged foods for years, it can be a challenge to think more critically about what you eat—but the effort will be reflected in your health.

“Even starting with the basics, you can make a huge change,” Razbannia said. “When you start the process of being cognizant of what you eat, things will change for you.”

Many diets that claim to promote healthy aging aren’t backed by evidence, and the data is general and vague. Stick to the established proof: Prioritize nutrient-dense fruits and vegetables and follow a Mediterranean-style diet, which emphasizes fish, poultry and plants.

Read: Why Is My Cholesterol High, and What Can I Do About It?

Another reason to focus on protein: Adequate protein intake builds muscle, which protects against frailty.

Frailty is an age-related decline in strength and the body’s ability to fight disease and recover from illness or injury. Sometimes, this manifests in falls, weakness or a susceptibility to frequent infections you can’t effectively fight.

Weight-related chronic conditions like cardiovascular disease and diabetes can also lead to frailty in older age.

"Frailty can be the difference between being able to endure chemotherapy or survive a stroke or a heart attack, and passing away from one of these conditions," Razbannia said. "The habits you embody can help you build resiliency."

Read: How to Think About Your Biological Age