Rapid Weight Loss? Not So Fast!

Boris Hansel, MD


November 18, 2014

Recently, the authors of a study published in The Lancet Diabetes & Endocrinology,[1] whose results have been widely reported by the mainstream press, sent a very strong message: We must stop advising patients who want to lose weight to do it gradually!

What did these researchers do? They tested two modalities of a low-calorie diet. The first regimen was a very low-calorie diet of 450 to 800 calories per day for 3 months. The second regimen was less restrictive and aimed to cut about 500 calories from the daily caloric intake for 9 months. In both cases, the plan included meal replacements from a well-known food brand. So the authors compared the effects of a short-term, very hypocaloric diet with a longer-term, mildly hypocaloric diet.

What results led the authors to place value on the very restrictive regimen?

First, patient adherence was better with the very low-calorie diet. Only 3% had discontinued the regimen versus 18% of subjects in the group on the mildly hypocaloric diet.

Second, this study showed that weight loss at the end of the regimen was similar (about 14 kg) with both methods. So there was an equivalence between the very low-calorie diet and the mildly hypocaloric diet at the end of the diet period.

Finally, the authors point out that in the longer term, meaning nearly 2 years after the end of the diet period, weight regain was similar, whether weight loss occurred quickly or slowly. The weight regained was approximately 10 kg at the end of the "stabilization" period ... which was actually not stabilization. Weight loss at the end of the study was therefore 4 kg in each group.

Their findings represent a real argument advocating rapid weight loss using meal replacements.

Here is my commentary regarding these results:

We know that one of the reasons our patients want to lose weight quickly is to try to find the motivation to continue the regimen long-term and then to adhere to a balanced diet. But if we look at the results of this study from another angle, we see that rapid weight loss does not help achieve permanent weight loss. So, one of the conclusions also is: What some of our patients call a "starter," and what they claim motivates them to eat a healthy diet, is not effective. This is only a starter and is not accompanied by a more sustainable weight loss had they not had the starter.

Moreover, we should keep in mind that rapid weight loss is not without side effects. In this study, one patient in the very low-calorie group had biliary complications that the authors attribute to rapid weight loss.

Finally, a study published simultaneously in Diabetes Care[2] showed that what matters most to manage cardiometabolic risk factors and prevent the onset of diabetes is weight loss over the long term (2 years) as opposed to short-term weight loss achieved after 6 months of dieting. This study confirms that, regardless of the proposed regimen, the long-term effect of diets on weight always seems the same: a 5% weight loss from the initial weight.

There is therefore no scientific argument to encourage our obese patients to lose weight rapidly—except, obviously, in cases with life-threatening complications. Even if they themselves request rapid weight loss, I think that we should not give in to this demand. Rapid weight loss mentality usually reflects that they have misunderstood the real reasons behind their weight problem. We should not respond with a prescription for rapid weight loss.

Editor's Note: This commentary is an edited transcript of a video presentation published on Medscape France on November 4, 2014.


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