Is Yo-Yo Dieting Harmful?

There has been the thought for years that repeated weight loss and regain - "yo-yo dieting" - is harmful. The consideration has been that this can result in weight loss being more difficult with each attempt due to change in metabolism as well as adverse effects on the body. Some research of different populations has shown that this might be the case with increased death rates.

A group of researchers at UCLA evaluated information from 480 participants in an outpatient weight loss program (Diab Obesity & Met 2007:9(3);379-385). The group had been drawn from a larger group of those in the program but the 480 males and females were those who had restarted the diet at some point during a 12 year period. The diet plan used is what is known as a Very Low Calorie Diet (VLCD). Such plans rely on intakes of only 700 to 800 calories per day.

When the researchers compared dieters with multiple starts (MS) to those single start (SS) participants they found them to be very similar at the beginning of their diets as age, race and initial Body Mass Index (BMI). Interestingly, more men than women were in the MS group. During retries at weight loss there was no difference in the rate of weight loss in either men or women and it didn't matter the number of tries -- each time they lost weight at about the same rate. Most participants maintained some weight loss between periods of being on the diet.

Likewise, there was no adverse effect on risk factors for heart disease such as cholesterol or blood pressure. In fact, all groups who lost weight had improvement in their cholesterol and triglycerides and drops in blood pressure from baseline (although there was better improvement after the initial diet session).

What this means for you

If you are struggling with a weight issue, keep working on a solution. We know that there's dramatic improvement in health whether the weight is lost slowly or quickly. Evidence shows that slow, steady weight loss appears to be more sustained weight loss, but this research proves that starting again is also beneficial.

First posted: March 28, 2007