What Is Weight Cycling?

Weight cycling means bouts of weight loss and regain, commonly known as “yo-yo dieting.” 

There’s substantial evidence showing that weight-loss interventions are ineffective in the long run for any but a tiny percentage of people. It’s actually very rare for people to “lose weight and keep it off.”

For example, a 2007 review of long-term weight-loss studies (Mann et al. 2007; CW for weight-stigmatizing language) found that the average amount of weight loss maintained across interventions was only a couple of pounds, so people who started out in the “obese” BMI category remained there. Some of the reviewed studies even found that people gained weight during the diet interventions. People were also still regaining weight at the end of the studies—and up to 66 percent of people actually regained MORE weight in the follow-up period than they lost during the intervention. 

The researchers in this review also found that the published results on the outcome of weight-loss studies are optimistic, for reasons including: 

    1. Weight-loss interventions have extremely high dropout rates—67 percent in the studies reviewed here—which makes diets appear to be more effective than they are, because only the people who are having relative “success” tend to show up for their follow-up visits. Those who regain significant amounts of weight are more likely to drop out.

    2. A substantial percentage of participants in weight-loss studies go on other diets after the studied diet ends, so their weights at follow-up are lower—and therefore the studied diet ends up looking like it had “better” long-term results than it actually did. 

    3. Most weight-loss studies don’t include control groups of non-dieters for comparison.

    4. These studies are generally based on self-reports of weight, which tend to overestimate weight lost.

As one of the reviewed studies put it, “It is only the rate of weight regain, and not the fact of weight regain, that appears open to debate.”

Speaking of which, the typical trajectory is for people’s weight to reach its lowest point at about 6 months into the intervention, and then it starts increasing at about the 1-year mark, at which point the rate of regain speeds up (Dansinger et al. 2007; CW). So in short, people trying to lose weight are more likely to weight cycle than not.

Weight cycling also has negative mental- and physical-health effects, again independent of BMI. It’s associated with a higher risk of binge eating (Field et al. 2004; CW), and with the following undesirable outcomes (Tylka et al. 2014; CW):

    • Higher mortality

    • Higher risk of osteoporotic fractures

    • Higher risk of gallstone attacks

    • Loss of muscle tissue 

    • Chronic inflammation

    • Some forms of cancer

    • Hypertension 

    • Cardiovascular disease 

    • Diabetes (Park et al. 2019; CW)

Both cardiovascular risk and mortality have especially robust support in the literature. Several studies from a huge data set of almost 7 million people in South Korea supported the findings that weight cycling is associated with cardiovascular and mortality risk independent of BMI. One of those studies found that sustained increases in BMI over time were associated with lower mortality risk, whereas both sustained weight loss and weight cycling were associated with higher risk. (Cho et al. 2017; CW). As a couple of studies have found, weight cycling may explain all of the excess heart risk seen in people in higher BMI categories (Bacon & Aphramor 2011).

Diabetes—another condition that often gets blamed on weight itself—is also linked to weight cycling. A 2019 study of more than 3.8 million adults (Park et al. 2019; CW) found that the people who weight-cycled the most were significantly more likely to develop diabetes within the 4-year follow-up period than those who weight-cycled the least—regardless of their baseline BMI.

In short, weight cycling is likely to pose a serious threat to the well-being of millions of people (especially those who are trying to lose weight), and eradicating it needs to be a top public-health priority.

To learn lots more about weight cycling and how it harms our health, check out my book, Anti-Diet: Reclaim Your Time, Money, Well-Being, and Happiness Through Intuitive Eating, and my podcast, Food Psych.