Top ranked diets of 2021: What works, what doesn’t, according to experts

The New Year often serves as a wake-up call for people wanting to eat healthier after spending the holiday months indulging in some of their favorite foods.

With that in mind, the U.S. News and World Report had an expert panel review more than 40 eating plans and then ranked the 20 best diets of 2021 to help people “lose weight and improve your overall health.” In the top spot was the Mediterranean diet, following by the DASH and Flexitarian diets in a tie for spot No. 2, followed by the WW, keto and Dukan diets.

Yahoo Life spoke with nutrition experts about the top-ranked eating plans — with some expressing surprise over how some diets made the cut.

The heart-healthy Mediterranean diet, high in vegetables, fruits, whole grains, beans, nuts, seeds, and olive oil, was rated the No. 1 diet of 2021. (Photo: Getty Images)
The heart-healthy Mediterranean diet, high in vegetables, fruits, whole grains, beans, nuts, seeds, and olive oil, was rated the No. 1 diet of 2021. (Photo: Getty Images)

Mediterranean diet

This heart-healthy, plant-focused eating plan was ranked as the best overall diet. The Mediterranean diet is high in vegetables, fruits, whole grains, beans, nuts and seeds, and olive oil, according to the Mayo Clinic. Fish, poultry, eggs, and beans are eaten on a weekly basis along with a moderate amount of dairy products, while red meat is limited. Unlike many diets, red wine is also allowed, in moderation.

The eating plan is designed to help stabilize blood sugar, improve cholesterol and triglyceride levels, and reduce heart disease risk, according to MedlinePlus, but some people lose weight on the Mediterranean diet by making healthier food choices.

Leah Groppo, a clinical dietician with Stanford Health Care, is not surprised this healthy eating plan landed on top, telling Yahoo Life, that “there are decades of research around this diet.” Groppo adds: “I love the idea of eating more fruits, vegetables, whole grains, beans, nuts, and seeds because they’re high in fiber and healthy fats, and provide us energy.”

Unlike fad diets, the Mediterranean eating plan is not overly restrictive, which makes it easier to follow and more sustainable. “No foods are off limits,” Keri Gans, registered dietician and author of The Small Change Diet, tells Yahoo Life. “It encourages a very healthy, well-balanced diet that includes plenty of healthy fats, 100 percent whole grains, nuts and seeds and plenty of fish. It includes low-fat dairy. There are no gimmicks. There are no foods that are banned. Even red meat is included, but they say eat more fish and poultry. It’s all encompassing and that’s what I love about it.”

As Groppo puts it, “It’s not even a diet — it’s a lifestyle.”

DASH diet

This healthy eating plan tied for second place with the Flexitarian diet (below). Like the Mediterranean diet, the DASH diet — which stands for Dietary Approaches to Stop Hypertension — also focuses on improving heart health.

The meal plan, which is based on studies sponsored by the National Heart, Lung, and Blood Institute (NHLBI), includes eating a variety of vegetables, fruits and whole grains, along with fat-free or low-fat dairy products, fish, poultry, beans, nuts and vegetable oils, according to the NHLBI. Foods that are high in saturated fat, including full-fat dairy products and fatty meats, are limited on the meal plan, along with sweets and sugar-sweetened beverages.

While the DASH diet is thought of a lower-salt plan, Gans explains that you can consume up to 2,300 milligrams of sodium (about 1 teaspoon) per day, which is the same daily amount recommended by the government’s Dietary Guidelines for Americans. (Americans have an average of 3,400 milligrams of sodium per day, according to the Food and Drug Administration.)

By watching your sodium intake and eating a variety of healthy, whole foods, the DASH diet helps lower high blood pressure and improve cholesterol levels, which reduces heart disease risk, according to MedlinePlus.

Although the DASH diet is designed as a dietary approach to controlling hypertension, Gans explains that you don’t have to have high blood pressure to follow this healthy eating plan. In fact, she says that most people should be eating this way anyway. “Overall, it’s emphasizing all the foods we’ve been told to eat,” Gans says.

Flexitarian diet

The Flexitarian eating plan, which was created by dietitian Dawn Jackson Blatner, consists of following a vegetarian diet most of the time — namely, eating a diet rich in vegetables, fruits, legumes and whole grains. However, you can still have some meat-based foods on occasion, while also limiting added sugar and sweets.

Gans likes that “you don’t have to cut out the foods you love — you just need to focus on being vegetarian more,” she says. By encouraging people to eat more plant-based meals and consume less meat, Gans says they can help lower the risk for heart disease.

“This is a plant-based diet that allows you flexibility,” says Groppo, who notes that plant-based foods are often high in fiber and tend to be lower in calories, while meat tends to be higher in saturated fat. Groppo adds that eating a well-planned vegetarian diet is “overall better for our body and our environment.”

WW (formerly Weight Watchers) diet

WW’s myWW program custom, flexible weight loss plan came in fourth, after the DASH and Flexitarian diets. The program uses WW’s SmartPoints system, which assigns numbers to every food and beverage based on the number of calories, as well as how much saturated fat, sugar and protein, they contain.

According to the plan, no foods are off limits. “Any diet that includes all foods I really can’t condemn,” says Gans.

While the other healthy eating plans are free except for the cost of food, WW does have membership fees, which start at $3.22 per week and go up to $13.85 per week. Gans says that the eating plan isn’t for everyone, but it may be helpful for those who need more structure and guidance. “It’s also all about the community of WW,” says Gans. “Those who do well it’s because of the community.”

Groppo says that “people can do really well on WW” and that with its points system, they’ve basically done all the “backend” calculations for you, “so you don’t have to count calories.” Groppo adds: “It does help you lower calorie intake and have healthier options.”

However, the experts were surprised by some of the other popular eating plans that made the U.S. News and World Report’s best diets list — namely, the keto and Dukan diets.

Keto diet

The keto diet has been a popular weight-loss plan in recent years, but not every nutritionist is a fan. Gans calls it a “diet of deprivation,” adding: “Atkins, supercharged, is really what it is.”

The high-protein, very low carb diet is meant to put a person’s body into ketosis — a metabolic state in which your body goes from using glucose as its primary fuel source to breaking down stored fat instead, explains Groppo.

Groppo tells Yahoo Life that some research shows the keto diet can help with weight loss, along with lowering blood sugar in people with type 2 diabetes (talk to your healthcare provider before starting the keto or any other diet). But, Groppo says, “It’s not a sustainable diet,” adding, “The diet is very restrictive. Normally when you want to improve your health or lose weight, you want to do something that’s sustainable.”

While the protein-heavy keto diet may have some benefits, Gans says there’s a “greater body of evidence” that shows “diets high in saturated fat” — which is primarily found in animal products, such as meat — “can cause heart disease.” Gans adds, “The jury is out regarding how long one can sustain the keto diet and what other health risks may be involved. We don’t know long-term.”

Dukan diet

Created by French physician Dr. Pierre Dukan, the Dukan diet was thrust into the spotlight after Kate Middleton reportedly followed it before marrying Prince William. The weight-loss plan has four phases: Attack, Cruise, Consolidation, and Stabilization. The high-protein, low-fat, low-carb diet allows followers to eat 100 foods (68 types of protein and 32 different vegetables), as well as a small amount of oat bran. Followers get to add on more foods as they reach different phases.

“Right away, when I hear anything with ‘phases,’ that should be a red flag because that, to me, is not a lifestyle,” says Gans, who calls the eating plan “so confusing.” Groppo also questions how healthy it is to cut out entire food groups as required in the beginning of the diet. “You would probably lose weight,” Groppo says. “But is it sustainable? I don’t think so.”

Whether you’d like to reach a healthier weight or simply want to eat better, Gans says that it’s important to focus on lifestyle changes that are sustainable, while also looking at how much sleep you’re getting, how often you’re physically active, and what your stress levels are. “Let’s not just look at our food intake, but our entire self,” Gans says.

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