The Dangers of Yo-Yo Dieting by The American Diabetes Association

The early days of 2021 will likely be filled with quick-fix diets promising to help you “lose the quarantine weight.” But you might think twice before jumping into a fad diet to lose weight fast.
Restrictive diets often lead you down a predictable path: you’ll stick with it at first, lose some weight, then eventually give in and start eating foods that were off limits, followed by regaining the weight you lost. Many of us have experienced this—perhaps many times before—but is it dangerous?

The Dangers of Yo-Yo Dieting

While most experts agree that losing weight can lead to many health benefits, how you lose weight is more controversial. Weight loss “diets” are unsustainable for most and often lead to “weight cycling”—a pattern of losing and regaining weight.

Some research shows that this pattern of “yo-yo dieting”—going back and forth between losing weight on a restrictive diet, then gaining it back when the diet ends—may be doing more harm than good.  

In a study published in 2017 in The New England Journal of Medicine, people with dramatic fluctuations in body weight were 78 percent more likely to develop type 2 diabetes over a period of about five years compared with those whose weight remained more constant.

Consequences of yo-yo dieting

Yo-yo dieting can lead to disordered eating habits and long-term struggles with weight. Engaging in unhealthy eating behaviors can have serious consequences, including an unhealthy relationship with food.

Another consequence for people with diabetes is that it disrupts your blood glucose management. “Consistency is a key factor for diabetes management,” says Toby Smithson, RDN, CDCES, a spokesperson for the Association of Diabetes Care & Education Specialists and coauthor of Diabetes Meal Planning & Nutrition for Dummies.

Although food isn’t the only thing that affects your blood glucose—medication, sleep, stress, and physical activity also play a role—it’s a key part. Drastically cutting back on calories can lead to dangerously low blood glucose, for instance, and overeating after weeks of deprivation can raise your levels.

Yo-yo dieting and insulin resistance

Research shows that yo-yo dieting may increase insulin resistance, a condition that occurs when your body can’t efficiently use the insulin it naturally produces.

Insulin resistance can lead to type 2 diabetes; for those who already have diabetes, it makes the condition far more difficult to manage.

That’s not all. Yo-yo dieting can also result in a loss of muscle mass. Overly restrictive, low calorie diets often lead to muscle loss along with fat loss. When you gain weight back, most of it tends to be fat rather than muscle.

Having a higher percentage of body fat increases insulin resistance and slows your metabolism. Because muscle burns more calories than fat, your body isn’t burning as many calories. So not only are you setting yourself up for high blood glucose, but you’re also more likely to hang on to the pounds you gained back.

Breaking the cycle

While weight loss can improve your health if you are overweight or obese, the secret to success is to focus on behavior changes rather than the number on the scale.

Eating a balance of nutrients in the right portions and getting more movement often improves A1C, blood pressure, cholesterol, and mood even if they don’t lead to weight loss.

Work with your health care provider to figure out which behaviors might lead to improved health. Focus on “baby steps”—making small changes gradually (instead of crash dieting) leads to sustained behavior changes that can lead to a lifetime of healthier living and weight management.

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