The Best and Worst Diets for Sustained Weight Loss According to Registered Dietitians

Losing weight is much easier in the beginning – but once you hit a weight-loss plateau it’s harder to lose those last few pounds with just exercise.

This is where diets come in since strict calorie limitations can break the plateau. The best diets are low-calorie, provide all essential nutrients, and are sustainable. The worst diets are too restrictive, don’t allow for leeway, and keep you starving and deprived making binging or cheating on your diet more likely.

There is a whole slew of dietitian-recommended diets you can try as per your requirements and food preferences. This article details some of the best and worst diets as per registered dietitians. Let’s look at each in turn.

4 Best Diets for Weight Loss

The Mediterranean Diet

This diet comes out on top as it’s a wholesome, plant-based diet that can be sustained because it’s mostly just a healthy, holistic lifestyle. The focus is on legumes, nuts, whole vegetables and fruits, olive oil, fatty fish, and occasionally some cheese/dairy and wine.

The diet is rich in fiber, vitamins, minerals, and proteins making it balanced and nutrient-dense. The diet helps in weight loss (if you eat less than 1500 calories/day), and also contributes to cardiac health, energy levels, and brain health/cognitive function rendering it a great overall diet.

It’s easy to follow as no food groups are avoided completely, and you don’t have to track your macros microscopically.


DASH is another hot favorite on successive polls, and the acronym stands for “dietary approaches to stop hypertension". The diet is best for heart health and also reduces your risk for Type 2 diabetes and stroke.

The diet cuts out trans fats and saturated fats from your diet like high-fat dairy and meats and emphasizes vegetables, fruits, and lean protein. The low-sodium, low-fat approach helps to lower cholesterol, blood pressure, bones, and joints and is also easy to follow without overhauling your entire meal plan.

*A combination of the DASH and Mediterranean diets is known as the MIND diet i.e., “Mediterranean-DASH Intervention for Neurodegenerative Delay” recommended for preventing cognitive decline disorders like Alzheimer’s/dementia and ensuring optimum brain function.

Flexitarian Diet

The flexitarian diet keeps the human need for variety and relief now and then to maintain discipline. The flexitarian diet is essentially just a semi-vegan/vegetarian diet, but you are allowed to have animal products from time to time.

This diet allows you to transition to fewer and healthier animal products and organically expand your plant-based diet at your own pace which lessens frequent and unhealthy cravings.

(WW) – Formerly known as Weight Watchers

This program has been around for a long time and continues to be very effective as they update their methods to appeal to new generations and their needs. Subscriptions can get you access to their app and digital assistance or a personal coach depending on the plan.

These provisions help you keep track of your weight loss in a systematic and guided manner, making weight loss more methodical compared to people who diet on their own causing fluctuations in intake and weight.

The points system, with ZeroPoint scores for healthy foods like legumes, fish, chicken, and nuts, for example, can keep you motivated and internalize the calorie count of different foods. This way you are conditioned to make better choices.

4 Worst Diets for Weight Loss

The Keto Diet

The keto diet is useful if you want quick and substantial weight loss. But it isn’t the healthiest option and is only safe when done under the proper supervision of a dietitian. This high-fat diet with moderate proteins and minimum carbs can result in headaches, migraines, lack of energy, muscle soreness, and constipation.

In addition, the restrictive macros are hard to keep a track of – exceeding the calorie count even slightly throws your body off ketosis, rendering all your effort till then useless as the weight will come back on.

Once you go back to normal food after the diet, you will certainly put the weight back on. The diet may be useful for people trying to keep diabetes under control and improve insulin resistance.

Atkins Diet

The Atkins diet is a protein-rich, low-carb diet divided into 4 phases- induction, balancing, fine-tuning, and maintenance. During the induction phase, you are only allowed less than 20 grams of carbohydrates and this is predominantly from low-carb vegetables. This is then slowly ramped up to healthy carbohydrate choices by the end of the diet once you reach your goal weight to ease you back to a normal diet. However, as legumes, high-carb vegetables, and whole grains are not permitted, fiber content is low affecting gut health and mood.


As the name suggests, this diet is based on the diet of the paleolithic hunter-gatherer communities. It is high in protein, fruits, vegetables, and nuts but prohibits legumes, potatoes, dairy, and processed foods.

While the elimination of processed foods is a move in the right direction, dairy, and legumes offer crucial vitamins and minerals the absence of which can affect yours adversely.

If Paleo is combined with a vegan diet, this restricts the available food groups further, like gluten-based foods. The “Pegan” diet is very difficult to abide by with many “off-limit” items, but it may have benefits in terms of reducing triglycerides and blood sugar.


The Whole 30 diet is technically sound as it eliminates processed and packaged foods which makes you more energetic, takes down inflammation, and improves sleep.

But it has been relegated to the worst diets in the recent past because following a 100% zero-sugar diet, without legumes, beans, dairy, and grains is incredibly hard. When so many food staples are off the table, it doesn't set you up for success even if it is just 30 days.


Some other good diets that may help you shed extra pounds include the TLC or Therapeutic Lifestyle Changes diet and Volumetrics Diet which are family-friendly and easy to adhere to, as long you are mindful.

Other diets worth trying out include the Nordic or the Mayo Clinic Diet.

Trend/fad diets that are a quick fix and not sustainable in the long run include juice cleanses, the Sirtfood Diet, the Baby Food Diet, and the Raw Food Diet, amongst others.

Updated on: 13-Apr-2023


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