Here’s why fad diets don’t work – explained in two simple charts

Low-carb, low-fat, Paleo, South Beach, gluten-free — while fad diets have their cult followings, two Canadian doctors say no matter what you follow, you won’t keep off the weight if you’re taking on an unsustainable diet.

In a new commentary published in the prestigious medical journal, The Lancet, two Canadian experts warn that fad diets garner the same results: yes, you’ll lose some weight at first, but after that you’ll plateau by the six-month mark and slowly regain the weight you worked so hard to lose.

“We leave ourselves open to someone coming up with the next fad diet making grand proclamations on why this is going to be better than the diets of the past, but all of these diets have been put head-to-head for clinical trials in weight loss and have shown similar results,” Dr. Kevin Hall, one of the commentary’s authors, told Global News.

“It’s not some magic diet that’s going to address this problem. We need to look at the factors that influence a person’s ability to sustain a healthy lifestyle,” Hall said.

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He’s a Cambridge, Ont.-raised scientist working at the U.S. National Institutes of Health. He collaborated with Dr. Yoni Freedhoff, a physician at the University of Ottawa and the Bariatric Medical Institute, for the commentary.

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Hall said the duo penned the commentary to address the research community: there’s an overload of studies stacking one diet against another, even though, ultimately, they end up with disappointing results in the long run.

They start off with great results: about 10 pounds in weight loss, but as their diet wanes on, dieters slip up on adherence. That’s when the weight creeps back on.

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The doctors pulled together data from a large, two-year-long study that compared low-fat diets next to low-carb diets. Here’s what they found:

The first chart illustrates the weight loss within the first six months. After that, the weight is packed back on and plateaus.

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In the second chart, the doctors show how difficult it is for dieters to keep up with a drop in calories. As the months wane on, dieters ate more regardless of being on the low-fat or low-carb diets.

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A major gap in weight loss research is understanding why some people thrive and succeed on a prescribed diet while others end up in failure.

While the message that fad diets don’t work in the long run may be disheartening for those trying to lose weight, Hall promises the commentary offers a silver lining. They’re calling on the medical community to focus on research that’ll uncover what makes a diet stick and what could be a trigger for failure.

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“[The message] is not very satisfying right now, but the encouragement [readers] should potentially get is it almost doesn’t matter which diet you try, the important factor is sustaining those changes,” he told Global News.
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“Crowning a diet king because it delivers a clinically meaningless difference in bodyweight fuels diet hype, not diet help,” Hall and Freedhoff wrote.

“It’s high time we started helping,” they said.

Read the full commentary in the Lancet.

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