5 Popular Weight-Loss Plans, Ranked By RDs

When you’re trying to slim down for good, it’s essential to choose an eating plan you can see yourself following for life. To help you find the right fit, we asked registered dietitians to break down how some of the most popular weight-loss plans work.

Here’s your introduction to five top diets, ranked from the most to least sustainable.

The Mediterranean diet takes the top spot because “it is filled with natural foods that are rich in filling fiber and protein which help you lose weight,” says Nataly Komova, RD. “It’s also low in unhealthy saturated fats and sugars, reducing your calorie intake.” Originally designed to protect heart health, numerous studies show it’s an effective weight-loss strategy, even more so when paired with exercise and a slight calorie deficit.

You eat like someone living on the Mediterranean with plenty of whole grains, leafy greens, fruit, beans and olive oil, some fatty fish and poultry, plus the occasional glass of red wine if you’d like. Cheese is fine in moderation, though limit red meat to once or twice a week max and try to keep processed foods out of the pantry.

LEARN MORE: Ultimate Grocery Guide: Mediterranean Diet

The Dietary Approaches to Stop Hypertension (DASH) diet was designed for the 47% of us who need to lower our blood pressure, but it can also lead to weight loss, per an analysis of 13 studies published in Obesity Reviews. 

It’s “easier and more realistic to follow” compared to other diets because it doesn’t call for eliminating any food groups, says Morgyn Clair, RD. Rather, the goal is to lower your sodium intake to less than 2,300mg per day (about 1 teaspoon of salt) by eating more vegetables, fruits and whole grains, some fat-free dairy products, fish, poultry, beans and nuts, and fewer foods that are high in saturated fat like red meat.

LEARN MORE: What 1,500 Calories Looks Like (DASH Diet)

Intermittent fasting is easier to maintain than some other diets because it adds structure (by focusing on when you eat) but there’s no need to completely overhaul your fridge and pantry, says Girgen. There are numerous ways to do it, but the usual setup is to shrink your eating window and in turn, take in fewer calories. One of the most approachable versions of IF is the 16:8 method during which you fast for 16 hours and eat for 8 (Think: a 9am–5pm eating window).

More research is needed, but some studies suggest IF could support weight loss and burn fat. One downside? A common mistake is to think you can eat whatever you want during your eating window — which isn’t the healthiest approach, notes Clair.

Rich in fruits and vegetables, a plant-based diet is low in calories and fats but makes you feel fuller longer thanks to high-fiber foods, which could help you slim down, says Komova. Research shows vegan diets result in the most weight loss, followed by vegetarian diets and meat-friendly diets. While vegan and vegetarian diets can be harder to stick with since you’ll need to cut out meat and animal products, a flexitarian diet in which you eat “meat-lite” offers a more flexible approach.

LEARN MORE: Ultimate Grocery Guide: Plant-Based Diet

In many ways, the keto diet is the opposite of the above eating plans: It’s high-fat, moderate-protein and very low-carb (Think: 20 grams a day or less than 1/3 of a bagel, with few fruits and vegetables).

The goal is to launch your body into a state of ketosis where fat is burned for fuel instead of carbs.

Rapid weight loss often follows and some studies show keto can be an effective slim-down strategy when followed closely, but it’s difficult to stick with long term, says Girgen. Barriers include limited options when you eat out and side effects like constipation, bad breath and headaches. You might also be tempted to load up on unhealthy fat sources, which harm your overall health. For these reasons, it’s best to consult with a healthcare professional before starting keto to make sure you’ve got a safe plan that fits your needs.

“The best diet is one that is easy for people to follow and doesn’t rely too much on restriction,” says Clair. If a diet is calling for too many restrictions and calorie-cutting, it’s probably not your best bet for lasting weight-loss success. Instead, look out for green flags like an emphasis on whole foods with simple guidelines, sustainable lifestyle changes, and a modest calorie deficit.

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