The Best and Worst Diets for Sustained Weight Loss (2024)

Is losing weight or eating better on your mind these days? There's no shortage of weight loss diets grappling for your attention. And the reality is that mostdiets— the good and bad — willhelp you shed poundsin the short term. The difference is in whether they'll help you keep them off, and that requires a doable plan that you can stick with for life. Usually, that means diets that cut out entire food groups (sorry,keto) or impose strict rules for eating (looking at you,Whole30) are likely out, unless they've been recommended to you for medical reasons by your healthcare team.

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Here, a few registered dietitians share details on the healthy, sustainable, and effective weight loss diets they want to see stay — and those they’d be happy to see take a hike in the new year.

The 4 Best Weight Loss Diets in 2022

1. Mediterranean Diet

U.S. News & World Reportranked this mostly plant-based eating approach its No. 1 overall diet in 2022, and registered dietitians such as Amy Gorin, RDN, the owner ofAmy Gorin Nutritionin Stamford, Connecticut, stand by that choice.

Gorin applauds theMediterranean diet— which is rich in whole vegetables, fresh fruit, whole grains, fatty fish,olive oil, nuts, legumes, and somered wineand dairy — because it’s a balanced way of eating. TheMediterranean diet’s focus on whole, plant-based foodsover highly processed junk foods or fast foods may make you more likely to stick with it.

“By default, if you’re eating healthier foods that are higher infiberandproteinand are eating lesssaturated fatand sugar, you will likely eat fewer calories and lose weight,” saysAmy Goodson, RD, who is based in Dallas-Fort Worth.

Beyond weight loss, there are the health benefits associated with eating like Italians, Greeks, and other people who live on the Mediterranean Sea (the diet’s namesake). This approach, Gorin says, also supports heart and brain health. For example, a previousreview published in the journal Metabolic Syndrome and Related Disorderssuggested that aMediterranean diet, especially when combined withexerciseand followed for longer than six months, was associated with reduced weight gain. The review involved 16 randomized controlled trials, which represented 1,848 people who followed a Mediterranean diet and 1,588 people who acted as the controls.

Weight lossanda healthier body? Win-win!

2. WW (Formerly Weight Watchers)

You know this popular weight loss plan by its previous name,Weight Watchers. In 2018, the company rebranded to make the program more aboutwellness, peran explainer on the WW website.

“This program is one of the most effective weight loss programs out there, promoting long-lasting, sustainable changes with many studies to back this up,” says Gorin, who previously wrote a nutrition blog for WW called The Eat List.

The newest version of WW, Gorin says, offers a customized program that the company touts as a holistic approach to weight loss.

One word of caution, says Goodson, concerns theZeroPoint foods. The number and type of foods that count as zero points differ depending on your color level (Green, Blue, or Purple) in the system. For everyone, fruit and nonstarchy veggies are zero points, which is great, as it encourages consumption of these fiber-rich foods that can make you feel fuller at meals and snacks (and are tasty, too). But if you are on Purple, the ZeroPoint foods includebananas,eggs, beans, legumes, and whole-wheat pasta (and more) — a detail that gives Goodson pause. “Bananas have 100 calories, and eggs have 70. I love both foods, but it can add up. Someone shouldn’t have the belief that they haven’t eaten anything by consuming these foods.Portion controlis still necessary,” she says.

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3. Vegetarian Diet

There are so many reasons forgoing vegetarian, includingenvironmentaland ethical considerations.

Weight loss, though, is another potential benefit of opting to eat plants instead of meat, according to a previous review of 12 randomized controlled trials representing about 1,150 people. Indeed, theMayo Clinic notesthat when you pay attention to portion size and food quality, avegetarian dietcan help with weight loss because the foods you'll eat (including whole ones like fruit, veggies, whole grains, and plant-based protein) contain fewer calories and fat but are more filling than foods found in a standard American diet, or SAD. The SAD is high in processed and packaged food that tends to be loaded with salt, sugar, and saturated fat.

Boosting your health may be another reason to adopt a vegetarian diet, and there’s science behind this choice. When carefully planned, “a vegetarian diet is a wonderful diet,” as it is high in nutrient-rich plant foods and low insaturated fat, says Jeanne Tiberio, a registered dietitian based in Salem, Massachusetts. In ameta-analysis published in November 2017 in the journal Critical Reviews in Food Science and Nutrition, a vegetarian diet was associated with a 25 percent lowerrisk of heart diseaseand 8 percent reduced odds ofcancer.

A word of caution: If you have a personal history ofeatingdisorders, you may want to sidestep this approach (and any other restrictive plan, for that matter). A previousstudy published in the Journal of the Academy of Nutrition and Dieteticsnoted that some people use a vegetarian diet to legitimize food restriction to aid weight loss. There can be many perks to going veg — but play it safe and ask yourself where your motivations lie before you make this choice.

4. Flexitarian or Semi-Vegetarian Diet

Whereas vegetarians eschew meat, aflexitarian dietallows you to add small amounts of animal products, like meat, poultry, or fish, for additional protein and satisfaction. And U.S. News & World Report ranks this sustainable approach No. 1 on its list of weight loss diets. If you’re looking to burn calories in a balanced way, this flexible approach may be a good match for you. “I like to think about following a plant-focused diet. Only 1 in 10 people are eating the recommended amount of fruit and vegetables in the U.S. By focusing on eating more plant-based foods along with high-fiber whole grains andlean proteinsand dairy, you can reach the number of fruits and veggies you need,” says Goodson.

Reducing but not necessarily eliminating how much meat you eat is generally positive. For instance, areview of 25 studies published in January 2017 in Frontiers in Nutritionfound that semi-vegetarian dietswere associated not only with weight loss but also with health benefits such as lower blood pressure and a reduced risk of type 2 diabetes. The authors concluded that although it’s a popular eating approach with women, men, too, may benefit — especially because guys generally consume more meat.

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2 Diets That Land in the Middle

1. Intermittent Fasting, or IF

Intermittent fasting (IF)is an increasingly popular way to lose weight fast — and it seems as if more people are becoming interested in it, says Goodson. The approach involves extended periods of not eating, and there areseveral ways to tackle it.

For instance, some people fast for two days out of the week (called 5:2, eating very little on fast days), while others set a specific eating window (like 16 hours fasting, 8 hours feeding). Others still might reserve a day where they don’t eat at all, says Goodson.

While research on this approach is still in its infancy, there is some evidence that it helps people lose weight, at least in the short term, per theHarvard T.H. Chan School of Public Health.This approach is not right for everyone, however, and that’s why it lands somewhere in the middle in our survey of healthy diets.

You really have to understand your needs and your schedule to know if it will work for you. “This eating style has a very restrictive nature and could lead to overeating orbinge eating, so it’s not a good fit for a person with a history ofdisordered eating,” says Gorin. Goodson also worries about athletes who are training in the morning. “If you go to the gym early in the morning and then don’t eat for several hours, this is counterproductive tomuscle recovery,” she says. That said, Goodson recommends it in certain situations, such as if you are an overweight person who is at risk of diabetes. If you have diabetes and are taking insulin to manage your condition,ask your doctor if IF is safe for you before starting.

2. MIND Diet

The MIND diet wasn’t designed for weight loss, which is why it falls in the middle. This diet wins accolades, however, because it shares striking similarities with the Mediterranean diet. In fact, MIND “is a cross between the Mediterranean Diet and the DASH diet [the acronym stands for Mediterranean-DASH Intervention for Neurodegenerative Delay] — so it’s a dietitian’s dream,” says Goodson. The diet is based on Mediterranean but emphasizes specific foods, such as leafy greens, berries, extra-virgin olive oil, nuts, fish, whole grains, and wine. (Just don’t start drinking alcohol if you don’t currently consume it, experts advise.)

The MIND diet focuses on promoting better cognitive health, says Goodson. A study published in April 2019 in the journal Alzheimer’s Dementia, for instance, found that participants who followed MIND had a 53 percent lower risk of developing cognitive impairment over 12 years. Though it doesn’t rank high on U.S. News’ ranking of top weight loss diets, it is generating a lot of buzz and is one Goodson predicts will become more popular. What’s more, as U.S. News points out, it is possible that you’ll lose weight following MIND, since the diet deemphasizes foods that are associated with weight gain, such as dairy, sweets, and fried foods. The website ranked the diet No. 4 in Best Diets Overall.

The 6 Worst Diets for Sustained Weight Loss in 2022

1. Carnivore Diet

The carnivore dietrequires eating mostly meat (along with someeggsand fat, likecheese). There’s also a popular version that involves eating only beef. Although you can findcarnivoredieters’ success stories online, don’t even think about it, says Gorin. “This is not a healthy or sustainable diet, and there are healthier ways to lose weight. Not only isthe carnivore dietextremely high in saturated fat, which can put you at risk for increasedcholesterollevels, it also leaves out a lot of foods that are really good for you,” Gorin adds. That includes fruit and veggies, which are known to promote weight loss and help fight disease.

Bottom line: Avoid this diet — or, if you're determined to try it, be sure to run the idea by your healthcare team and get their take first.

2. Whole30

There’s nothing wrong with the foods thatWhole30asks you to eat, like fresh fruit and veggies. In fact, proponents of the plan say that focusing on whole foods instead of packaged, processed ones may result in weight loss and other health perks, too, like higher energy and improved sleep.

But the Whole30 plan prohibits many dietary staples — not justunhealthy foodslike added sugar and alcohol but also legumes, dairy, and grains. And while your body doesn’tneedthose healthy foods to function, Whole30’s restrictions can make the program difficult to stick with. “This diet wasn’t designed to be sustainable — it’s meant to be a 30-day thing. But if you can’t maintain a diet for more than 30 days, why are you doing it?” says Goodson. If you are someone who finds motivation in a diet “jump start,” then Whole30 might work for you, but make sure you have a plan for how you’re going to sustain healthful choices after the month, she says.

Strict rules can create a cycle of guilt around food, saysAnne Mauney, a registered dietitian in Washington, DC. Even if you follow through on the entire 30-day program, at the end you’re likely still going to feel down on yourself for eating what was once deemed “bad.”

Plus, when you go back to eating these foods, “you may end up eating more of them than you need or want, because there’s that sort of ‘screw it’ mentality, where you’ve already started eating something you ‘shouldn’t’ have, so you might as well keep going. This can turn into a sort of ongoing restrict-binge cycle over time, where you limit certain foods and then end up overdoing it on those foods later, before going right back to restricting and trying to be ‘good,’” Mauney says. That’s no way to live.

3. Keto Diet

If you want to lose weight quickly, this diet, which researchers designed to help controlepilepsyin children, has become a popular way to do so.

But there’s a lack of definitive research proving that keto is safe and effective for the long haul. What we do know is this high-fat, moderate-protein, and very low carb diethas a reputation for being challenging, especially if you’re doing it without medical supervision. When you go off the plan, you may gain back all the weight you lost.

What’s more, for all the buzz about the health benefits of keto(for type 2 diabetes, certaintypes of cancer,Alzheimer's disease, and more), long-term randomized, controlled trials in humans are lacking, Harvard notes. “Keto restricts foods that help fight cancer and heart disease, like whole grains and legumes,” says Tiberio.

There are manyways to approach keto, and not all of them are healthful. “Though you should be eating a lot of spinach andkaleon keto, people generally eat bacon and eggs,” says Tiberio, which leaves out important disease-fighting nutrients, includingfiber.

But the eating plan can be useful in certain populations, says Goodson. “Overall, I don’t love keto, especially for exercising people. But if you have diabetes and have uncontrolled blood sugar, this approach can help you lose weight, balance those numbers, and get you back on a healthy eating plan,” she says.

Still, if you are following this diet, it’s important to focus on diet quality, which means including high-fiber foods, lean proteins, and healthy fats rather than saturated-fat-rich foods like butter and bacon.

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4. Atkins

Of course, theAtkins dietwas the originallow-carb diet, made popular decades ago. Now that keto is on the scene and there’s a popular carb phobia, you may be thinking again about going on a low-carb diet likeAtkins. (Atkins and keto differin thatAtkinsallows for more protein, whereas keto limits protein.)

“As with many diets, you lose weight quickly on Atkins. But it does not work long term,” says Tiberio. On theU.S. Newsrankings ofbest diets, Atkins doesn’t rank, potentially because of worries about safety and negative impact on heart health, as the website has previously noted.

5. Paleo-Vegan (‘Pegan’)

Fusing the popularpaleo dietwith someveganprinciples, the pegan diet has you eating loads of fruits and vegetables, along with nuts, seeds, and oils; eliminating dairy andgluten;and limiting beans and grains. It’s not traditionally “vegan,” whichpreviousresearchhas linked to weight loss and in which you eat no animal products of any kind, as it allows for a small amount of meat.

While the pegan diet hasn’t been researched for weight loss or other benefits, it’s likely to help you reduce your blood sugar andtriglycerides, says Tiberio.

Still, the fact remains that it’s a restrictive diet with many rules. Translation: You may lose some weight and boost your health temporarily, but chances are you won’t be able to follow this unbalanced way of eating forever. The fact is that many people struggle to maintain diets that contain a long list of off-limits foods. Those hurdles put this diet mashup on the “avoid” list for weight loss, per RDs.

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6. Cleanse Diets

Juice cleanses or other types of cleanse dietsare ineffective for long-term weight loss. “Many people try these in the beginning of the new year, but there is zero science behind their health benefits,” says Goodson. “You do not need something tocleanseyour body — that’s what you have a liver and kidneys for,” she says. These types of diets often require buying expensive bottled juices, supplements, or small meals. Her advice is to save your money.