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As we leave a season of festive gluttony in 2017 and resolve to cleanse our souls in the new year, an annual spotlight is once again shone on the diet industry.

It might have been one of the most-searched health-related terms last year, but the fat-burning ketogenic diet has already fallen out of fashion, ranking joint last in the U.S. News & World Report’s annual list of the best diets for the year ahead.

The popular low-carb diet has tied with the protein-based Dukan diet, rumoured to be favoured by the likes of Jennifer Lopez and Katy Perry.

Both diets advocate low levels of carbohydrates, the idea being that by prioritising other macro-nutrients, you put your body into an efficient fat-burning  state that results in rapid weight loss.

However, dieters embarking on these plans typically experience fatigue and lightheadedness as their bodies adjust to the deficiency of carbohydrates.

Experts on the report’s panel compile the list by looking at the long-term effects, ease and weight loss success.

It’s considered a highly credible source in the diet and health industry, meaning that the keto and Dukan diets probably have a rocky year ahead.

With the keto diet, the panel expressed concerns at the high fat content, which accounts for 70 per cent of the dieter’s daily intake.

This means that your carbohydrate levels drop drastically below the guidelines while on this plan.

According to nutritionist and CNNcontributor Lisa Drayer, the restrictive carb allowance equates to just one apple a day.

"The keto diet is just not sustainable over the long term,” she said.

“It doesn't teach you how to acquire healthy eating habits. It's good for a quick fix, but most people I know can hardly give up pasta and bread, let alone beans and fruit."

Meanwhile, the celebrity-favoured Dukan Diet consists predominantly of protein and include a 10 day “attack” period in which the dieter consumes as much as they want, so long as it is exclusively protein i.e. lean beef, veal, pork, fish, eggs etc.

Such a limited plan could result in nutritional deficiencies, the experts claimed, in addition to other unpleasant side effects such as bad breath and constipation.

The winning spot was also a tie, occupied for a second year-running by the DASH (Dietary Approaches to Stop Hypertension) diet and the Mediterranean diet.

The former is designed to combat hypertension and is rich in fruits, vegetables and lean proteins while the latter has been praised for lowering the risk of developing heart disease.

Both of these diets were deemed the healthiest by the panel of experts thanks to the emphasis placed on whole foods and grains.

While the DASH also ranked top in the panel’s “best diets for healthy eating” list, the Mediterranean diet came first in the report’s “easiest to follow” and “best plant-based diets” list.