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. Yet, a study published in the journal Metabolism failed to show that repeated yo-yo dieting slowed resting metabolism or hindered the ability to lose weight. Even among habitual diet cyclers, yo-yo dieting didn’t seem to interfere with the response to a subsequent weight loss diet. Interestingly, both weight cyclers and non-cyclers, in the study, were similar in the amount of body fat or muscle tissue they lost in response to dieting and dieting and exercise. Plus, there were no differences between the groups with regard to appetite hormones, like leptin, insulin sensitivity, or blood pressure.
It’s not surprising that the results in humans aren’t consistent. So many factors could impact the results of yo-yo dieting studies. How quickly did the participants lose the weight? What type of diet did they eat? Was it a repeated pattern over many years? Factors like age and sex could influence the results too. So, it’s hard to reach a conclusion. Yet, the preponderance of evidence doesn’t show a strong association between weight fluctuations due to yo-yo dieting and health problems or a that weight cycling makes it harder to lose weight long term.
How about the Impact on Self-Esteem?
Where weight fluctuations, due to yo-yo dieting, may have the greatest impact is on confidence level and self-esteem. Repeatedly losing weight and regaining can lead to a sense of frustration and failure and, according to some studies, depression. When a person’s weight goes on a rollercoaster ride, it can send their emotions reeling too. It’s not a healthy pattern to get into. Yo-yo dieting may be accompanied by disordered eating habits that could signal the onset of an eating disorder.
The Bottom Line
Although the evidence that yo-yo dieting is harmful to health in humans is rather weak, the pattern of dieting and then regaining the weight is frustrating from a well-being standpoint. Who wants to lose weight only to regain it again and again? That can be a real confidence buster too. The only meaningful weight loss is that which is sustainable and comes from a healthy lifestyle you can stick to long term, not just to lose weight for a wedding or party. Most people do best without measures like extreme calorie restriction and over-exercising. You might get by with it short-term but, eventually, you burn out.
Plan to lose any unwanted weight slowly, by making healthier dietary choices and committing to regular physical activity. Don’t judge yourself on how many pounds you’ve lost but on how good you feel. Even if good nutrition and exercise don’t lead to immediate weight loss, behind the scenes, it’s improving your metabolic health and lowering your risk of future health issues. Too often, we focus on nutrition and exercise as a means to weight loss without considering the other important benefits a healthy lifestyle offers.
NY Times.com. “Yo-Yo Dieting May Be Harmful to Heart Patients”
Mayo Clinic. “Is Yo-Yo Dieting Dangerous?”
Science Daily. “Yo-yo dieting does not thwart weight loss efforts or alter metabolism long term, study finds”
Metabolism, 2012; DOI: 10.1016/j.metabol.2012.06.012
Psych Central. “Yo-Yo Weight Loss is Sign of Disordered Eating”
Psych Central. “Mice Study Suggest Gut Bacteria Influence Yo-Yo Diet Results”
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