Yo-yo dieting is a familiar term to many. It refers to individuals who diet to lose weight, regain the weight over time, and then repeat the cycle. For some, this cycle has been repeated over and over and over again, even for decades. You may hear medical professionals refer to this as “weight cycling.”
This has been going on long enough for a large number of people that the scientific community is beginning to collect long-term data on health outcomes for this subset of the population. The results are not promising.
The first item of note is that the very term “yo-yo” implies that the weight loss was not maintained. The weight was regained. But how many dieters fall into this category? Almost all of them. Estimates vary, but most experts quote between 90 and 98 percent of dieters regain all the weight they lost while dieting. Most gain back more than they started with. A 2007 UCLA study analyzed a collection of 31 long-term studies on dieting and found that in the two years following weight loss, 83 percent gained back more weight than they had lost in the first place. Five years down the road, 50 percent of the dieters were more than 11 pounds heavier than when they had started.
These rapid changes in weight and body composition are detrimental to our metabolism. When people lose weight quickly on a restrictive diet, they often lose muscle mass. Muscle is highly metabolically active, so when you lose it your metabolism drops. When yo-yo dieters regain weight, they often aren’t regaining all the muscle mass they lost; instead, they gain body fat.
Another recent study at New York University found that yo-yo dieters had more than double the risk of death, heart attack, and stroke than those who maintained a stable weight. Overall they were likely to be heavier and have high blood pressure as well.
This effect is even observable in yo-yo dieters who fluctuate within a “healthy” weight range. Even if an individual’s high and low weight in their “yo-yo” range are within a healthy BMI, their risk of diabetes, high blood pressure, and heart disease are still increased.
What’s the takeaway from this information? Don’t make changes in your diet that you can’t stick with. Weight loss is an appropriate goal for many people who are overweight or obese, but don’t achieve it by doing things you won’t sustain. For most people, this means that weight loss will take time; odds are, drastic changes will lead to quick weight loss but also a return to their previous weight over time. Don’t “diet”. Dieting implies that it’s a temporary change, and there are few diets that are realistic to follow long-term. As I’ve heard other dietitians say, “A diet is something you have, not something you do.”