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What you eat and don’t eat can reduce your risk of medical conditions such as heart disease and cancer and increase life expectancy, according to decades of research. But while much of the advice focuses on what not to eat, I also wanted to learn more about when and how people can eat to optimize their health.

I spoke with CNN wellness expert Dr. Leana Wen about foods that she recommends people should eat more of and what other food habits to consider. Wen is an emergency physician and adjunct associate professor at George Washington University. She previously served as Baltimore’s health commissioner.

CNN: Let’s start by reviewing the evidence. How much does what you eat influence your health?

Dr. Leana Wen: According to one 2022 study, people can add up to 13 years of life by following a diet that has more vegetables, fruits, whole grains and nuts. A 2023 Nature study found that people can gain more than 10 years in life expectancy based on their dietary habits. The biggest gains came from consuming less sugary beverages and processed meats, while eating more whole grains, nuts and fruits.

Another 2023 study tracked over 100,000 participants for over 30 years to assess long-term dietary habits. This study found an association between healthy eating patterns and a 20% risk reduction of early death. People who ate more whole grains, fruits, vegetables, nuts and legumes “were also less likely to die from cancer, cardiovascular illness and respiratory and neurodegenerative disease,” according to the researchers.

CNN: What kinds of foods do you counsel patients to eat more of?

Wen: I encourage people to increase their consumption of whole foods that are minimally processed. Think leafy green vegetables, fresh fruits and whole grains. Some nutrition experts also advise that people think about having a food rainbow, meaning an assortment of fruits and vegetables in a wide variety of colors and ingredients. People should also consider eating more legumes, such as beans and lentils, and incorporate nuts like walnuts, pistachios and almonds into their meals.

CNN: What about fish and meat?

Wen: These can also be part of a healthy diet. Fish contains omega-3 fatty acids, which some studies have associated with reducing the risk of heart disease as well as dementia. Lean meat can also be a good source of protein. Studies have linked highly processed meat with negative health outcomes, so once again look for minimally processed whole foods. Think salmon fillet and roast chicken, not hot dogs and chicken nuggets.

CNN: What should people eat and drink less of?

Wen: Based on the data, I’d urge people to reduce their consumption of sugar-sweetened beverages like sodas and energy drinks. I’d also urge them to cut out ultraprocessed foods, which includes junk food like chips and candies.

This is not easy to do because of the sheer amount of sugar-sweetened beverages and ultra-processed food around us. The health outcomes, though, are clear. According to one study involving more than 11,000 adults, people who had a high consumption of ultra-processed food had a 31% higher risk of mortality compared with those who reported the lowest level of consumption of these foods.

It’s helpful for people to think not just about how to cut out these foods but about what they will replace them with. Those who drink a lot of sodas can, of course, switch to water, but if that doesn’t yet work for them, they could try sparkling or flavored water, or a small amount of juice diluted in water. Those who snack on chips and pretzels can try swapping them out for nuts.

I’d urge everyone to be intentional. Look at the labels on the food you are buying. If there is a long list of ingredients on the package including many chemical names, this is probably high-processed food. Consider replacing this with minimally processed whole foods.

CNN: We’ve talked about foods to eat and to avoid. Does the number of meals matter? Is it better to snack or not?

Wen: This part is more contentious because there is conflicting evidence. On the one hand, there are studies that demonstrate the health benefits of having breakfast and small meals throughout the day. On the other hand, some diets that involve limiting the number of meals has also shown positive impacts. It would not be good to eat healthy meals but then have unhealthy snacks.

To snack or to snack may depend on your specific circumstances. Someone who finds themselves so hungry during the day that they end up resorting to fast food for dinner would clearly benefit from a healthy snack and then a planned dinner instead. Others who cannot easily limit snack quantity or for whom snacks might disrupt their established routines do not need to start snacking.

There is one food habit related to timing that I would encourage, which is not eating just before bed. Doing so could increase heartburn symptoms and interfere with sleep. Try to complete your last meal at least two hours before going to sleep.

CNN: Why should we think about how we eat? 

Wen: It’s important to examine not just what and when people are eating but also how. Are your meals usually on the go, when you have to eat really rapidly? If so, you may end up consuming primarily ultra-processed food, including fast food. Also, you may not be allowing your body to send you signals of satiety.

Do you find yourself often stress-eating and reaching for food when you are anxious about something? That may prompt a re-examination of your relationship with food and whether you should seek resources to assist with stress and mental well-being.

READ MORE: How much ultraprocessed food are you eating? Find out here

Are you always eating alone? If so, consider planning mealtimes as opportunities to gather with other people. Take a break from work, put down your devices, and be intentional about spending time talking with those you are sharing a meal with.

This habit has at least three positive effects. First, this prompts more thought around what food is being served. Second, it creates healthful behaviors around food, which includes allocating the time needed to eat, digest and have your body tell you when you are getting full. Third, social connection is also an important contributor to good mental and physical health and to longevity.

Food, of course, is not the only factor that determines people’s health and well-being. Other factors, including exercise, sleep, stress and underlying medical conditions, also play a major role. But food is one component, and there are day-to-day-decisions about what we are eating, when and how that can make a big difference in health outcomes.