Yo-yo dieting gets a bad rap from most people. It has been linked to everything from lower life satisfaction to increased risk of mortality. As someone whose weight has fluctuated by around 30lbs during adulthood, I was keen to discover whether yo-yo dieting is as deadly as many claim it is. The truth I discovered was both enlightening and relieving.
Here’s the bad news: there are plenty of studies that link yo-yo dieting with various unpleasant conditions. I’ve already mentioned lower life satisfaction and increased risk of mortality, but you don’t have to look too far to find arguments for yo-yo dieting’s contribution towards increased abdominal fat, high blood pressure, heart disease, and cancer. I could go on.
The good news is that all of the above mentioned studies and opinions are either lacking in conclusiveness or arguably not worth the paper they’re written on.
Take a 1996 article by Robert W. Jeffery in The American Journal of Clinical Nutrition as an example. While the article concludes that “all patterns of weight change other than stable weight appear to be associated with increased mortality risk,” that rather bold statement is qualified by the following:
A key requirement for inferring causality from observational data is … lacking in the current research literature, namely biologic plausibility. To date, no mechanisms have been identified … that might mediate an association between weight variability and ill health.
Although epidemiologic data on weight variability and health are intriguing, they are at present insufficient to alter public health recommendations regarding weight control.
In other words, Jeffery admits that while his findings are statistically intriguing, they prove nothing. He recognises that correlation does not necessarily lead to causation.
Jeffery’s respect for due scientific and statistical process may shed new light on any yo-yo dieting study you care to mention. All of the arguments I have found regarding the effects of yo-yo dieting are laden with qualifying statements – words like “appears” and “may be”. Just about anything can be argued as potentially true if you qualify your statement appropriately, but doing so does not make it true.
In short, having researched this topic at length, I can find no conclusive evidence to support any arguments for the negative health implications of yo-yo dieting. And although conventional wisdom rails against the concept of yo-yo dieting, there are a number of studies in circulation that confidently state it is not proven to be unhealthy, nor make future weight loss any more difficult. Here’s a particularly compelling statement courtesy of The American Journal of Clinical Nutrition:
…weight cycling [is not] associated with an impaired ability to lose weight. Moreover, we did not find that weight cycling was associated with increases in depression, disordered eating … the percentage of weight as fat, or abdominal obesity.
I’ll conclude with the final statement in Jeffery’s article:
Maintaining a lean body weight throughout life is recommended. Weight loss in those who are obese and in those with obesity-related health conditions is also warranted.
Those are the obvious ideals that we know we should work towards. However, we shouldn’t necessarily beat ourselves up if our weight fluctuates within reasonable bounds.