You may have known people whose weight moves up and down like a yo-yo. They go on a calorie restricted diet short-term to lose weight for a special occasion and then return to their old habits and quickly regain the weight once the big event is over. When this becomes a repetitive pattern, it’s called weight cycling or yo-yo dieting.
For some people, yo-yo dieting is a way of life. These folks have a weight that fluctuates 10 or 20 pounds or more based on whether they’re currently in “diet mode” or not. Even when weight loss is successful, they eventually regain it, only to start the cycle all over again. Not only is this counterproductive since the weight loss isn’t lasting, but experts have questioned whether such weight fluctuations could be harmful or even dangerous.
Is Yo-Yo Dieting Dangerous?
According to a recent study published in the New England Journal of Medicine, weight fluctuations MAY potentially be harmful. When researchers compared people in the lowest quartile of weight variability with those in the top, they found some disturbing associations. Those whose weight fluctuated most had a 136% greater risk of heart attack, a 117%greater risk of heart attack, a 78% greater risk of type 2 diabetes, and a 124% higher risk of premature mortality. Furthermore, yo-yo dieting could be particularly risky for people who already have heart problems, type 2 diabetes, or high blood pressure.
Although these associations sound scary, not all studies show that weight fluctuations, related to yo-yo dieting, are harmful. Plus, showing a link between weight fluctuations and heart problems, stroke, and type 2 diabetes doesn’t mean that weight fluctuations and yo-yo dieting CAUSED the issues. It simply demonstrates an association. It could be that people who are predisposed to these problems fluctuate in weight more because they’re already unhealthy. Health issues can trigger weight fluctuations as well.
Does Yo-Yo Dieting Predispose to Obesity?
Another question is whether yo-yo dieting makes obesity and weight regain more likely. The reasoning goes something like this. You over-restrict calories to lose weight and your metabolism slows in response. Then, you return to your old lifestyle habits and regain the weight. Now, your metabolism is a bit slower than before due to the extreme calorie restriction and it’s easier for you to put back on the weight you lost and more. Makes sense, doesn’t it?
Yet studies looking at this issue are mixed. Mayo Clinic found that just over half of 19 studies looking at weight cycling and obesity showed an association, meaning weight cycling seemed to increase the risk of obesity. Three out of eight studies also showed that weight cycling and fluctuations increased the risk of future weight gain. They concluded, based on the results, that there’s not enough evidence to say that weight cycling predisposes to obesity.
You may have also heard that yo-yo dieting “trashes” your metabolism – that each time you lose and regain weight, your metabolic rate slows.