Fad diets are a dime a dozen, and they wiggle their way into conversations and onto our social media feeds each January. A new Forbes Health/OnePoll survey of more than 1,000 adults found that 33 percent of 18 to 25-year-olds and 30 percent of 41-year-olds’ top New Year’s resolution was to eat a better diet.
But popular diet plans, like keto, consistently rank near the bottom of medical and nutrition experts’ lists of recommended diets.
However, “what not to eat” and “which plans not to follow” only help so much. What should you eat to boost your overall health? A new survey spanning nearly four decades has provided us with actionable advice—and it’s not restrictive or one-size-fits-all.
In fact, various eating patterns can reduce disease and premature death, according to the new study, which was spearheaded by researchers at Harvard T.H. Chan School of Public Health and published online on Jan. 9.
“The take-home message from this study is that there is no single diet that is the best diet for everyone. A healthy diet can be flexible and adapted to meet individual health needs, food preferences and cultural traditions,” says Frank B. Hu, MD, PhD, one of the study’s authors and a professor and chair of the Department of Nutrition at Harvard T.H. Chan School of Public Health.
What are they, and how can you incorporate these foods into your daily life? Nutrition experts dished.
About the Cohort Study
The new study was large and long-term. It included more than 75,000 women and 44,000 men. No participant had cancer or cardiovascular disease before the study. Every four years, participants completed dietary questionnaires, which researchers scored.
Many of the patterns that emerged aligned directly with these diets and guidelines:
- The Mediterranean diet: Focuses on lean proteins like fish and chicken, fresh produce and healthy fats like olive oil and avocado. It was recently ranked as the top diet for 2023 by US News & World Report.
- Healthful plant-based: Similar to the Mediterranean diet, but animal products like poultry and cheese don’t make the cut.
- Dietary Guidelines for Americans: Updated every five years by the USDA and HHS, these guidelines recommend focusing on lean and plant-based protein, fruits and veggies while limiting red meat, processed food, alcohol and added sugar.
- Alternative Healthy Eating Index: Developed by Harvard researchers, this study rates foods based on risk for contributing to or limiting risk for chronic diseases.
One dietitian says the new study offers hope for people who don’t necessarily want to craft a menu based on one particular “type” of diet.
This study indicates that one does not need to stick to only one healthy dietary approach for their whole life. To enhance variety and adherence, one can switch between these various healthy diets or create their own flexitarian diet. However, the core healthy eating principles should remain the same: Eat more minimally processed plant foods such as fruits, vegetables, nuts, whole grains and legumes; eat less red meat and ultra-processed foods high in sugar, sodium and refined starch.
“The study summarizes that various eating patterns can protect against mortality related to heart disease, cancer or respiratory diseases,” says Kimberley Rose-Francis, RDN, CDCES, CNSC, LD. “This is in contrast to the one or two dietary patterns historically touted as healthy eating patterns, like the Mediterranean diet. This new research demonstrates that nutrient-dense foods from different cultures and food preferences promotes good health.”
Eat These Foods to Increase Your Life Expectancy
Each plan mentioned by Harvard researchers has its nuances. But they also have key similarities worth highlighting as you craft your grocery lists.
“Although these diets differ in some aspects, they all include high amounts of healthy plant foods such as fruits, vegetables, whole grains, nuts and legumes and lower amounts of refined grains, added sugars, sodium, and red and processed meats,” Hu says.
Experts went dug into the data and provided actionable advice.
People may resort to low to no-carb diets to lose weight. But experts suggest taking a different route. Instead of cutting carbs, reach for whole grains.
“Whole grains are important to regularly consume in our diet as our brain uses these as our first energy source,” says Kayla Kopp, RD, LD, a registered dietitian with Cleveland Clinic’s Center for Human Nutrition. “Whole grains, compared to white grain products, have more fiber and help to keep us fuller longer. Fiber is crucial for blood sugar control, cholesterol control, as well as keeping our bowel movements regular.”
Indeed, another large recent cohort study from 2020 indicated that participants with the highest intake of whole grains had the lowest risk for Type II diabetes. A study from 2022 found that high consumption of total whole grains was linked to lower cardiovascular disease risk.
Figuring out what’s truly whole grain requires a bit of savviness because of misleading marketing, though.
“If the food package is labeled with ‘multigrain,’ ’12-grain bread’ or ‘made with whole grains,’ still check the ingredient list,” says Rose-Francis. “These words are savvy marketing buzzwords companies use that may be confusing and may not even contain whole grains.”
What are you looking for?
“Foods that have whole grain or whole wheat listed as the first ingredient,” says Stephanie Magill, MS, RD, CD, FAND, adding that she recommends getting at least five servings per day.
- Brown rice
- Whole wheat pasta
You’re likely not surprised fruits made this list. But your first thought may not be “carbohydrate source” when you think of fruit. Produce is a natural form of sugar and fiber—and, of course, vitamins.
“Fruit contains lots of potassium, vitamin C and folate, which our population doesn’t tend to get enough of,” Kopp says.
Because fruits have natural sugar, people, such as those with diabetes, will want to pay close attention to portion sizes and how they consume fruits.
“If you are someone who needs to control your blood sugar…It is ideal to consume a fruit with a source of protein or healthy fat,” Kopp says. “For example, eating apple slices with peanut butter or an orange with a piece of string cheese…can aid in preventing spikes in blood sugar.”
Speaking of sugar, reach for whole fruit over juice.
“Juice is higher in calories and doesn’t have the beneficial fiber that a whole piece of fruit has,” Magill says.
Some of Kopp’s top recommendations for fruit include:
Opting for seasonal fruits can up their appeal.
“For example, the best types of fruit to purchase [in January] are apples, clementines, grapefruit, kiwis, kumquats, lemons, oranges, pears, persimmons and tangerines,” Kopp says.
You’re also likely not surprised that vegetables made the cut.
They are a great source of vitamins, minerals and fiber and contain the least number of calories for someone who may be trying to lose weight,” Kopp says.
But Kopp and Magill say they see people struggle to incorporate them into their diet. Magill suggests getting five servings per day. Variety is the spice of life, after all—and may even help you (finally) eat enough veggies.
“The key with fruits and vegetables is to eat a variety of types and colors so that you can get the benefits from all the nutrients,” Magill says. “Eating a variety of colors and textures also makes meals more visually appealing and eating more enjoyable.”
If you want to eat seasonally, Magill recommends going to farmer’s markets, some of which continue indoors during the winter.
“During the winter months, it is best to purchase kale, Brussels sprouts, carrots, Swiss chard, parsnips, collard greens, radishes and red cabbage,” Kopp says.
Some of Kopp’s top recommendations for non-starchy vegetables include:
- Bell peppers
- Green beans
No-fat, like no-carb, is another no-go based on this study and dieticians’ recommendations for healthy individuals.
“Nuts are considered a healthy, unsaturated fat source that aid in improving inflammation, lowering cholesterol and decreasing the risk of developing heart disease,” Kopp says, adding that these fats can also be obtained from other sources like avocados and olive oil.
Portion size is key, though.”It is recommended to stick with no more than ¼ cup nuts at a time because they are calorically dense even though they are healthy,” Kopp says.
Magill notes that about a ¼ cup of almonds provides almost 200 calories and around 15 grams of fat.
“Legumes are important for controlling your blood pressure, lowering your cholesterol and balancing blood sugar in the body,” Kopp explains. “They can also help to support healthy gut function and aid in weight management as they are very high in fiber.”
She suggests adding black beans to your taco next time you observe Taco Tuesday. Other sources she recommends include:
Remember, there’s no one-size-fits-all plate. And Kopp notes that people at risk for or living with certain conditions and on medications, like kidney disease, high cholesterol or diabetes, may need additional guidance. Even some veggies may need to be limited.
“There are specific conditions, like kidney disease, where an individual may need to be cautious of the specific kinds of vegetables they are ingesting,” Kopp says. “This is why it is best to work with a registered dietitian if you are unsure.”
Frank B. Hu, MD, PhD, one of the study’s authors and a professor and chair of the Department of Nutrition at Harvard T.H. Chan School of Public Health
- Kayla Kopp, RD, LD, a registered dietitian with Cleveland Clinic’s Center for Human Nutrition.
- Kimberley Rose-Francis RDN, CDCES, CNSC, LD
- Stephanie Magill, MS, RD, CD, FAND
- Best Diets Overall 2023. U.S. News and World Report.
- Bilodeau, K (2022). Scoring highly on Alternative Healthy Eating Index lowers risk for many illnesses.
- Davis, S (2022). 50% of Gen Z cite this health improvement as a top new year’s resolution for 2023.
- Healthy Eating Index, FDA.
- Shan, Z, et al (2023). Healthy eating patterns and risk of total and cause-specific mortality.
- Yang, H, et al (2020). Intake of whole grain foods and risk of type 2 diabetes: results from three prospective cohort studies.
- Yang, H, et al (2022). Intake of whole grain foods and risk of coronary heart disease in US men and women.