Best and Worst Weight Loss Diets: Pros, Cons, Research

To help assist your diet choice process, here are the most popular diets today and their pros and cons. Read on to see which plan is best for you — along with which ones to avoid.

Ketogenic Diet (Keto)

This high-fat, adequate-protein, low-carb fad diet sends the body into a state of ketosis, in which the body uses stored fat for energy instead of carbohydrates. Past research suggests that the ketogenic, or “keto,” diet can be an effective weight loss method, but to be successful, you must follow the plan consistently with no cheat days — otherwise, you’re just eating a high-fat diet that may be high in unhealthy fats for no reason.

Although the keto diet is popular among people with type 2 diabetes, you should avoid this diet if you have type 1 diabetes or other specific metabolic disorders.

But no matter what your current state of health, you should speak with your physician before beginning the ketogenic diet.

One of the diet’s biggest hurdles is hitting the low levels recommended for carbohydrates, says Hultin. “This diet likely means a lot of planning and bringing food with you to parties and events.” It may also cause side effects like keto-related diarrhea and constipation, fatigue, mood swings, headaches, and bad breath.

These symptoms are a common part of the so-called “keto flu,” which happens as your body adjusts to burning fat rather than carbs for fuel, experts say.

Pro tip: If you’re planning on doing the diet, check out a complete keto food list and read up on the healthiest fats for keto diet followers.

Paleo Diet

“A lot of people think the foundation of a paleo diet is high-fat meat, but I suggest that it’s vegetables,” says Hultin. The concept is to eat only foods — including meat, fish, poultry, eggs, fruits, and vegetables — that would have been available to our Paleolithic ancestors. This means grains, dairy, legumes, added sugar, and salt are all no-nos.

This diet involves lots of menu planning and preparation. One small clinical trial with 32 participants found that it could help people with type 2 diabetes lose fat, but the Academy of Nutrition and Dietetics warns that the plan could leave you low on carbs, plus it doesn’t allow for nutrient-dense foods like whole grains, legumes, and dairy.

You’re also at risk of missing vitamins and minerals like calcium, vitamin D, and B vitamins.

Not getting enough bone-fortifying nutrients like calcium can also put you at risk for osteoporosis (bone loss).

Atkins Diet

This low-carb, high-protein diet has been around for decades. In fact, some say the keto diet is the new Atkins, though these popular low-carb plans are markedly different.

According to the Atkins website, the plan works in phases, with a very low daily net carb allowance of about 20, 40, or 100 grams in the first phase, meaning the diet may send you into ketosis. How many net carbs you need to stay under depends on the plan you opt for. (You can calculate net carbs by subtracting fiber and sugar alcohols from total carbs. This value, though an unofficial nutritional term, can give you an estimate of how much a food might affect blood sugar levels.)

Unlike the keto diet, you’re allowed more carbs as the phases continue.

In one past review, researchers found that the Atkins diet can yield modest long-term weight loss, similar to that of the WW (formerly Weight Watchers) eating plan.

Because the diet is low in carbs, it may not be appropriate for someone who is on insulin or has diabetes — and because it’s high in protein, you’d want to avoid it if you have kidney disease.

DASH Diet

The DASH diet, or Dietary Approaches to Stop Hypertension, is mainly focused on reducing sodium intake and increasing consumption of fruits and vegetables.

“This is a great way of eating that I highly recommend to many clients, and I even model in my own life,” says Elizabeth Shaw, RDN, who is in private practice in San Diego and is the coauthor of Fertility Foods Cookbook. “Since the premise of the diet is designed to help people who have high blood pressure, low-sodium foods are recommended. But considering that most Americans exceed their daily sodium levels anyway, it’s not surprising that dietitians recommend this style of eating for treating many different conditions, such as heart disease and obesity.”

In one review, people with prehypertension and mild hypertension who followed the DASH diet saw an improvement in blood pressure compared with a control group who did not follow the DASH diet.

U.S. News & World Report has also consistently listed the DASH diet as a top diet in its annual rankings.

MIND Diet

The MIND diet, or Mediterranean-DASH Intervention for Neurodegenerative Delay, is a sort of hybrid between the DASH diet and the Mediterranean diet. It features foods meant to slow the progression or development of Alzheimer’s disease, the most common form of dementia, and an incurable neurodegenerative condition that more than six million Americans are living with.

Some research backs up this notion, including one study that found a link between following the MIND diet and a reduced risk of dementia, though more research is needed.

This eating pattern typically emphasizes vegetables, berries, beans, whole grains, olive oil, and fish, while calling for a reduction in saturated fat and trans fat.

Because the MIND diet focuses on eating whole, fresh foods, people who follow this eating pattern may lose weight while doing so.

Low-Carb Diet

Many diets, including Atkins and the keto diet, fit into this umbrella. A typical low-carb diet plan suggests 60 to 130 grams of carbohydrates per day (very low-carb diet plans are typically less than 60 grams per day), but this can vary.

One review reported that people following a low-carb diet experienced weight loss and a reduction in body fat, and it may also help improve blood glucose control — yet study authors note that the long-term effects of the diet require further research.

Following this type of eating plan can result in certain nutritional deficiencies, and it is not recommended for children or for pregnant or lactating women. Very low-carb diets can also be dangerous for people with diabetes on insulin, due to the risk for hypoglycemia (low blood sugar).

South Beach Diet

Created by the cardiologist Arthur Agatston, this low-carb diet features three phases. The first phase is the most restrictive, limiting carbs such as potatoes and rice. Each subsequent phase becomes more lenient, and the diet emphasizes lean protein, unsaturated fats, and low-glycemic carbs such as nonstarchy vegetables. In general, the South Beach Diet aims to promote lasting lifestyle changes.

There are very few recent studies on the weight-loss effects of the South Beach diet.

However, one past study of people with metabolic syndrome following the first two phases of the diet noticed significant weight loss, but also experienced higher hunger levels during the diet.

Like other low-carb diets, the South Beach Diet isn’t appropriate for children or for pregnant or lactating women.

Intermittent Fasting

There are many ways to do intermittent fasting — ranging from fasting for a number of hours each day up to an entire 24-hour fasting period one or two times a week. “If you’re trying to kick a habit like eating late into the night, then stopping eating earlier in the evening and fasting overnight could be beneficial for you,” says Hultin. “There are many types of intermittent fasting, so ensuring you pick one that works for you and your lifestyle is important.”

While its long-term efficacy for weight loss is unclear, reviews have found that 8 to 12 weeks of intermittent fasting may lead to a 3 to 8 percent reduction in body weight. The catch is, intermittent fasting performed just as well as other calorie-restricted diets.

“Intermittent fasting can be really challenging if you have an ever-changing schedule,” adds Hultin. “If you’re traveling and crossing time zones, it could be very difficult to follow. It might be best for people with more stability in their lives.” Intermittent fasting isn’t safe for people with type 2 diabetes, children, pregnant or lactating women, or anyone with a history of disordered eating.

Dubrow Diet (16:8 Diet)

If you want to kick intermittent fasting up a notch, you may consider the Dubrow diet, popularized by the husband-and-wife duo Terry and Heather Dubrow. On this diet, you’ll fast for 16 hours and eat for eight, also called the 16:8 eating plan, a type of intermittent fasting. Over three phases, you will also limit calories, fat, and carbohydrates, which may aid weight loss, say registered dietitians.

This eating plan takes a whole-foods approach, and calls for avoiding processed and packaged foods, along with sources of refined carbs and desserts in general. One downside is that the plan limits nutritious complex carbs.

WW (Formerly Weight Watchers)

In September 2018, Weight Watchers International announced that it would be changing its name to WW, in what many outlets dubbed a rebranding effort. Their goal: to make the eating and lifestyle approach about wellness rather than only weight loss.

With Oprah as one of its most notable proponents, this eating plan has been around for years. Jean Nidetch founded the organization in the early 1960s, according to the WW website. It’s gone through many iterations, its most recent version being WW PersonalPoints. On this plan, you’ll take a personal assessment, which takes several lifestyle factors into account in order to give you a holistic, all-over approach to weight loss and your PersonalPoints.

Evidence suggests that WW’s plans promote long-lasting, sustainable changes, and in 2024, U.S. News & World Report ranked it the best diet for weight loss. There’s little current research on this diet; however, one past clinical trial found that people following WW were close to nine times more likely to lose 10 percent of their body weight than those on self-help diet plans.

WW might also be a good option for you if you like the idea of community support. Connect is a members-only social community for people following a WW approach, and many people find that this support is key to their success. In fact, research shows that online support groups are highly effective at helping people lose weight.

Plus, WW has also begun offering access to weight loss medications such as GLP-1 receptor agonists for eligible users through its WeightWatchers GLP-1 Program.

Plant-Based Diet

Plant-based eating can take many forms, from vegan to vegetarian to pescatarian and flexitarian, which contains some meat. (Read about specific plant-based diets below.) All plant-based diets focus on eating whole, fresh foods such as vegetables, fruits, whole grains, nuts, seeds, and legumes. Research suggests that, in general, plant-based diets are associated with a reduced risk of various chronic diseases, including obesity, heart disease, and type 2 diabetes.

Vegan and Vegetarian Diets

A vegan or vegetarian diet is best for people who do not like to consume animal products or by-products, for health, environmental, or animal welfare reasons. There are several benefits of eating mostly plant-based foods, including a potential reduction in chronic disease.

There’s a large spectrum of these types of diets. For example, vegans consume no animal products, whereas ovo-lacto vegetarians eat both dairy and eggs.

Research has shown that this eating style can help you lose weight, though keep in mind that cutting out meat does not automatically make you healthier. Depending on the diet, it’s possible to become nutrient deficient.

Pescatarian Diet

Pescatarians are vegetarians or vegans who also eat fish. Prioritizing fish as your main protein can provide a bounty of health benefits, such as a lower risk of stroke and heart disease. In fact, a portion of fish twice a week may reduce the risk of fatal and non-fatal cardiovascular disease outcomes by about 10 percent.

Flexitarian Diet

You can think of the flexitarian diet as a plan for part-time vegetarians. With this approach, plant proteins, whole grains, nuts, seeds, and fruits and veggies will be staples, with the occasional meat dish thrown in.

Because the diet isn’t as restrictive as a traditional vegan or vegetarian diet, it may be simpler to stick with — hence its No. 2 ranking in U.S. News & World Report’s Easiest Diets to Follow category. Because you’ll be eating meat some of the time, you may also be at a lower risk of the aforementioned nutrient deficiencies that vegetarians and vegans may face.

While there isn’t a wealth of research on this eating approach, U.S. News points out that, because of the focus on plants, those who follow the flexitarian diet tend to weigh less than meat eaters and have a lower risk of certain conditions, such as heart disease and diabetes.

Mediterranean Diet

The Mediterranean Diet is meant to reflect the eating pattern of people living in the Mediterranean. So, think plenty of vegetables, fruits, olive oil, fish, nuts, beans, legumes, and only a moderate amount of red wine and dairy. “Diets such as the Mediterranean diet are sustainable, have been shown to improve health, and aren’t restrictive or short-term,” says Asche.

Research shows that this diet is helpful for weight loss and reducing the risk of conditions like diabetes, heart disease, and Alzheimer’s disease.

It’s also been consistently ranked as the top diet in the U.S. News annual rankings.

Whole30 Diet

This popular diet program is fairly restrictive — and for the first 30 days, dieters must cut out grains, legumes, most dairy, added sugar, and alcohol without any slip-ups, according to the Whole30 website. The aim is to “reset” your body and adopt dietary habits that result in weight loss. Cutting out added sugar and alcohol has merit, but all the restrictions prove challenging and could lead to nutrient deficiencies and disordered eating.

“The Whole30 Diet does not allow for any whole grains or legumes, which are extremely beneficial to your health,” says Asche. “Whole grains are rich in fiber and micronutrients and are linked to helping to lower your risk of heart disease. The fact that the diet eliminates nutritious foods is a big red flag for me.”

Mayo Clinic Diet

This diet, created by Mayo Clinic, is a scientifically sound way to lose weight and lead a healthier lifestyle. To help participants learn which foods to eat and which to limit, the clinic created a nutritious food pyramid that emphasizes fruits, vegetables, whole grains, lean proteins, and healthy fats in small amounts. You can find it on the clinic’s website.

In the initial two-week “Lose It” phase, participants can drop 6 to 10 pounds. In fact, a recent survey reported that participants lost 13 percent of their body weight within six months on the Mayo Clinic diet.

Anti-Inflammatory Diet

Though not always followed for weight loss per se, an anti-inflammatory diet is rich in whole foods (including fresh fruits and veggies), and low in packaged, processed ones (like french fries and pastries), so there is a chance you will still shed pounds with this approach.

Usually, folks follow this diet to help prevent or treat chronic diseases, such as heart disease, diabetes, arthritis, depression, Alzheimer’s, and cancer. This is smart, considering inflammation has been linked to an increased risk of several chronic health conditions.

Adopting this diet is relatively simple. It isn’t focused on counting calories or carbs, and it doesn’t require any specific protocol. Instead, it’s more about the quality of what is on your plate. “The anti-inflammatory diet focuses on foods with nutrients that can calm systemic inflammation in the body, such as herbs, spices, tea, and cocoa. Another benefit of this diet is that it can be very flavorful because of the focus on seasonings,” adds Hultin, who also wrote Anti-Inflammatory Diet Meal Prep.

Low-FODMAP Diet

Designed for people with irritable bowel syndrome (IBS), the low-FODMAP diet limits certain types of carbohydrates called fermentable oligosaccharides, disaccharides, monosaccharides, and polyols — FODMAPs for short. These are essentially short-chain carbs that the gut has difficulty absorbing, thereby stimulating IBS symptoms.

The low-FODMAP diet is not intended for weight loss and, because it’s so restrictive, it is only recommended by doctors for short periods of time.

Intuitive Eating

Unlike commercial diet plans, intuitive eating doesn’t require you to buy packaged food from a specific brand. And unlike fad diets, it doesn’t ask you to count macronutrients or calories.

Instead, this approach lets you eat everything and requires regularly checking in with your body to know when you’re full. It sounds simple, but it can be a sustainable way to approach nutritious eating, for weight loss or otherwise, say Evelyn Tribole, RDN, a private practitioner in Newport Beach, California, and Elyse Resch, RDN, who coined the term “intuitive eating” in 1995.

(Tribole and Resch coauthored the groundbreaking book Intuitive Eating: A Revolutionary Program That Works, and their more recent book, The Intuitive Eating Workbook: Ten Principles for Nourishing a Healthy Relationship With Food.)

Satiating Diet

Similar to intuitive eating, the satiating diet isn’t strict — the main thing it calls for is eating whole foods, like apples, oatmeal, peppers, and salad. The idea is that these fiber-, protein-, and fat-rich foods promote a feeling of fullness, so you’re less likely to overeat.

There’s legitimate science behind prioritizing these foods over packaged ones. In fact, plenty of research show that diets higher in protein and fiber (along with exercise) can increase satiety and help weight loss efforts.

One past randomized controlled trial also found that men with obesity who followed the satiating diet (instead of a higher-carb diet) lost more fat and weight, and had more success sticking to the eating plan.

Volumetrics Diet

The veteran nutrition researcher Barbara J. Rolls, PhD, created Volumetrics, an eating approach that closely resembles the satiating diet. Dr. Rolls, who is currently the director of the Laboratory of Human Ingestive Behavior at Penn State University in University Park, Pennsylvania, argues that prioritizing whole, energy-dense foods, including beans, whole grains, lean meats, and fresh fruits and veggies, can help with weight management.

There’s very little research on whether the Volumetrics diet is effective for long-term weight loss and maintenance. One 12-week clinical trial of 37 healthy adults saw reductions in body weight and body mass index (BMI) while following the Volumetrics diet, but the study was too small and short to determine its sustainability and efficacy.

Nutrisystem Diet

If you don’t want to commit to counting calories, monitoring macronutrients, or meal planning, the Nutrisystem diet may be a good option. While on this eating plan, you’ll sign up to receive premade, low-calorie meals delivered to your home, as outlined on its website. (Nutrisystem foods are also available on Amazon.)

With Nutrisystem, each meal has a fixed amount of calories based on your age, sex, and any dietary requirements you may have. Generally speaking, the macronutrient composition of your meals will be high in protein, with moderate amounts of carbohydrates and fat.

The key factor for weight loss on this diet is your calorie deficit: Nutrisystem meals are designed to provide you with 1,200 to 1,500 calories a day, allowing you to lose weight while staying nourished.

Be mindful of a few things before you commit: Most research surrounding this diet’s effectiveness is funded by Nutrisystem, and while these studies have reported short-term weight loss in participants, the evidence for long-term maintenance is somewhat limited.

Also, the cost of Nutrisystem meals for one person per month works out to about $300 minimum, and you’ll want to supplement them with fresh fruits and veggies, nutrient-rich carbohydrates, and what the plan calls “extras” or “free foods” (such as condiments or add-ons) to make your plate more palatable. Lastly, the bulk of your diet will consist of prepackaged foods, which may not appeal to you if you usually prepare and enjoy fresh foods.

SlimFast Diet

As the name implies, the SlimFast diet claims you can lose weight — fast — by limiting your food intake to SlimFast-brand shakes for breakfast and lunch, a low-calorie meal (500 to 600 calories) of your choice for dinner, and three 100-calorie snacks per day. (Amazon, Walmart, and Target have SlimFast shakes and bars available for sale.)

While that may sound complicated, the weight loss mechanics of this diet are simple: Per the SlimFast website, you’ll limit your daily caloric intake to 1,200 calories for women or 1,600 calories for men, which will put you on track to lose a moderate amount of weight initially. Over time, your rate of weight loss will likely slow as your body adjusts to your new routine. Once you’ve hit your goal weight, you can replace one of your daily shakes with a second “sensible” meal of your choice.

The SlimFast diet comes in several categories, depending on your dietary needs, including SlimFast Keto and SlimFast Diabetic Weight Loss. You’re likely to lose weight following this diet, but the plan’s reliance on shakes may feel unappealing or repetitive. Also, the shakes and snacks are highly processed — meaning you’ll need to balance your diet with nutritious, whole foods like fruits, vegetables, and whole grains to lose weight healthily.

Nordic Diet

This diet focuses on the traditional diet of people who live in Nordic countries — Denmark, Finland, Iceland, Norway, and Sweden. Overall, this eating pattern is whole food–focused, plant-based, and features lots of seafood; it also emphasizes the sustainability of one’s food choices.

The foods included in the Nordic diet are nutritious and have been linked to positive health benefits. One systematic review and meta-analysis found that following a Nordic diet is associated with “small, important” reductions in body weight and BMI, as well as in the risk of heart disease, stroke, and type 2 diabetes. That may be in part because the diet can help lower LDL (“bad”) cholesterol.

In general, this diet requires you to make most of your food at home and forgo processed foods, both drastic changes that can be a barrier for some people.

Blue Zones Diet

So-called “blue zones” are five locations around the world where inhabitants are 10 times more likely than the average American to live to age 100. They are Okinawa, Japan; Sardinia, Italy; Nicoya, Costa Rica; Ikaria, Greece; and Loma Linda, California. The traditional diets enjoyed in these places are a major factor in their effect on longevity.

Research shows that an emphasis on anti-inflammatory foods and stopping when 80 percent full are two dietary factors in the blue zones diet that help citizens eat moderate amounts of nutritious foods. (A decrease in stress and a strong sense of community are other driving factors.)

Research has also shown that eating more plant-based foods (which are often anti-inflammatory) is associated with a lower risk of heart disease and death from any cause in middle-aged adults.

This is a plan that’s focused on eating more nutritious foods, rather than overt weight loss. You might lose weight depending on what your diet consisted of prior, especially if you’re decreasing your overall caloric intake.

Whole Foods Diet

Nope, this isn’t a reference to eating all of your food from the grocery chain Whole Foods. Rather, the diet is a call to prioritize whole foods in their least processed form (like fruits, vegetables, legumes, whole grains, lean meats, nuts, and seeds), while avoiding ultra-processed ones.

The whole foods diet is more of a guideline than a diet with set rules. The diet has no formal definition and there’s limited data on how it’s practiced, so it’s open to interpretation for each person doing it (which can be a major plus, as it’s relatively easy to follow).

Research shows that consuming ultra-processed foods contributes to excessive calorie intake, which can lead to weight gain.

One randomized controlled trial from 2017 found that people following a whole foods, plant-based diet had significant improvements in BMI, compared with the control group, after six months.

That said, not all processed foods are created equal. Lightly processed foods, such as frozen fruit without added sugar or canned beans without added salt, can be nutritious, convenient, and help you stick to a nutritious diet. On the whole foods diet, it’s more important to avoid ultra-processed foods like frozen dinners, cakes, cookies, sugary drinks, potato chips, and processed meats.

Those with a history of disordered eating may want to avoid this plan, as it can become easy to overly fixate on clean eating and the ingredients in each meal.

Elimination or Exclusion Diet

This is not a weight loss diet, so going on an elimination or exclusion diet should come with no weight-related expectations. Instead, this category of diet helps you identify foods that may be causing food allergies.

The food elimination diet is a two-phase eating plan. In phase one, you’ll stop eating certain foods or food groups for a specific time period; in phase two, you’ll slowly reintroduce them into your diet one by one and watch for symptoms to reappear.

If you experience symptoms during reintroduction, you’ll learn what types (or portion sizes) of foods trigger your symptoms. Some common foods that may be eliminated include dairy products, wheat, eggs, soy, tree nuts, and shellfish.

Popular elimination or exclusion diets include the low-FODMAP diet, gluten-free diet, lactose-free diet, and more. Doing an elimination diet can be challenging, and it’s important to connect with a knowledgeable registered dietitian who can help guide you through it.

HMR Diet

HMR stands for Health Management Resources, and it’s a diet that’s been around for more than three decades, according to the diet’s website.

Ranked as the ninth best fast weight loss diet by U.S. News & World Report, the HMR diet is a low-calorie diet that relies on food replacements via portion-controlled shakes and entrées from HMR, plus fruits and vegetables.

The purpose of the diet is to promote fast weight loss. After you have lost the weight, you enter the maintenance phase, which helps you slowly move from meal replacements to cooking and purchasing your own food. There is limited research regarding the HMR diet’s efficacy, plus you have to take into account the cost of the meal replacements, as well as supplemental fruits and vegetables.

If you have a preexisting medical condition, talk to your doctor before starting a low-calorie diet like the HMR diet.

Asian Diet

There isn’t an official “Asian diet,” but this eating plan is based on the traditional diets of people living in Asian countries. Overall, this diet emphasizes plant-based foods and minimizes dairy and red meat. Specifically, it emphasizes rice, noodles, fruits, vegetables, legumes, soy, nuts, seeds, and tea. You can also consume alcohol occasionally. Making these overarching changes to your diet can help improve your health.

There isn’t a wealth of data available on Asian-style diets, but some evidence suggests that people living in these regions enjoy benefits of some of the elements in their diets, such as the focus on fish in Japan.

Ornish Diet

The Ornish diet is an eating plan that focuses on sustainable, long-term lifestyle changes. On this plan, you’ll prioritize plant-based foods like fruits, vegetables, legumes, whole grains, and low-fat or nonfat dairy products, per the program’s website. It’s a low-fat diet, meaning fat should make up only 10 percent of your daily calorie consumption; you’ll avoid saturated fats in favor of healthy fats like those found in fatty fish, nuts, and seeds. You’re also encouraged to implement healthy lifestyle changes, like managing stress with meditation or yoga and adding a half-hour of daily exercise to your routine.

U.S. News & World Report consistently lists the Ornish diet among the most nutritious eating plans for heart health, and it notes its potential for weight loss, thanks to its focus on whole and plant-based foods.

Optavia Diet

The Optavia diet, formerly known as the MediFast, is a commercial eating plan that comes with prepackaged meals. There are three plans designed to aid weight loss or maintenance, per the Optavia website. Proponents say that the Optimal 5&1 Plan can lead to a 12-pound weight loss in 12 weeks, but there is no rigorous research on the Optavia diet.

Also, some registered dietitians argue that the eating approach doesn’t teach people how to change their eating and lifestyle habits for the long haul.

Climatarian Diet

The climatarian diet is centered around eating in a sustainable way, which means whole, plant-based foods. “In light of all the compelling evidence supporting the environmental benefits of plant-based diets, I strongly advocate embracing a diet like this that’s rich in fruits, vegetables, legumes, nuts, seeds, fish and seafood, and whole grains,” says Hultin. Research shows that plant-based eating is associated with weight loss, as well as improved cardiovascular and metabolic health.

Jenny Craig Diet

The Jenny Craig diet is a weight loss program that requires you to purchase food from a specific meal plan, which includes prepared meals, snacks, bars, or shakes. (Packaged Jenny Craig foods are available on the brand’s website and Amazon.)

On this plan, you don’t have to worry about calorie counting — calories and macronutrients have already been accounted for in the eating program. Some research has found that people following Jenny Craig lose weight over the course of 12 months, but it can be expensive, and it doesn’t teach you long-term dietary habits to maintain weight loss.

Green Mediterranean Diet

The green Mediterranean diet is similar to the original — which includes whole grains, fruits, vegetables, beans, nuts, and olive oil — but it’s slightly more restrictive. On this diet, it’s recommended that you avoid red and processed meats entirely, limit poultry, and include consumption of a duckweed (a superfood plant) shake, green tea, and walnuts daily.

One study found that following a green Mediterranean diet is superior for supporting heart health, compared with a traditional Mediterranean diet or a control group. (Both types of Mediterranean diets promoted a similar weight loss, about 12 to 14 pounds over six months.)

Longevity Diet

The longevity diet, developed by the director of the USC Longevity Institute, Valter Longo, PhD, promotes whole-grain carbohydrates and plant-based proteins and fats, as well as limits eating hours to 12 per day and fasting for longer durations intermittently.

“The research conducted by people like Dr. Longo and the Blue Zones Project provides compelling evidence for the effectiveness of longevity diets,” says Hultin. She’s on board with the diet’s call to eat more plant-based foods, but she encourages talking to a registered dietitian first before fasting.

Vegetarian Keto Diet

The keto diet, which is a high-fat, low-carb plan, is known for being pro fatty meats (bacon!), but a vegetarian keto diet turns that on its head. On a vegetarian keto diet, you focus on plant foods higher in healthy fats, like chia seeds, avocado, olive oil, and nuts, as well as cheese and eggs.

For vegetarians who rely on a lot of high-carb foods like pasta and crackers, transforming their diet in this way could lead to weight loss, though it can feel very restrictive and put you at risk of nutrient deficiencies.

Keto and Intermittent Fasting

This spin on the keto diet puts time parameters on when you can and cannot eat. One opinion paper from several U.S. university researchers suggests that keto-IF could be used to treat certain medical conditions, such as obesity, hypertension, inflammatory bowel disease, and neurodegenerative diseases, among others.

However, you should talk to your healthcare provider before combining these approaches, especially if you have diabetes and the timing of your food matters for blood sugar control and medication schedules.

TLC Diet

TLC diet stands for Therapeutic Lifestyle Changes, and it has good evidence behind it. In fact, the diet was created by the National Institutes of Health to help people at risk of heart disease reduce their cholesterol levels.

In research, the majority of people who had abnormal blood work at the start of the diet decreased their total and LDL (“bad”) cholesterol, triglycerides, fasting glucose, and insulin resistance. The diet was also effective for reducing BMI and waist circumference in people who were overweight or had obesity.