Are there Benefits to ‘Yo-Yo Dieting?’

Weight loss is crucial for improving health and decreasing disease risk in those with overweight and obesity. Unfortunately, many individuals who lose weight through lifestyle interventions (nutrition and exercise) and bariatric surgery don’t sustain the loss, and those taking anti-obesity medications typically regain the weight when they discontinue the drugs.

Repeated cycles of weight loss followed by weight regain (“yo-yo dieting”) is regarded as having deleterious effects. But is this perception accurate? And is it better for people to remain consistently overweight/obese or to lose weight, at least for a period of time, only to regain it?

The Biology Behind the ‘Vicious Cycle’

Weight regain is common, especially among those who have lost weight through lifestyle modifications. In these patients, approximately 30%-35% of lost weight is regained within the year, and half return to their baseline weight by the fifth year.

“Our body compensates when we lose weight,” Michael Weintraub, MD, clinical assistant professor, Department of Medicine, NYU Grossman School of Medicine, New York City, told Medscape Medical News. “Our cravings increase. Our basal metabolic rate decreases, and we burn less energy. These push back against the weight loss we attain with lifestyle modifications.”

This “energy gap” creates a hyperphagic response and rapid, efficient weight gain. According to one review paper, this results in “a vicious cycle of obesity, followed by weight loss, followed by weight regain, and so on.” 

Biologically, the deck is stacked against those who lose weight. One year after dieting, the levels of gut and adipose tissue hormones (eg, leptin, insulin, ghrelin) remain different from their baseline values, promoting increased appetite and weight regain. Neuroendocrine adaptations following weight loss result in suppression of the thyroid hormone axis, reducing energy expenditure and promoting weight regain. Another hypothesis implicates a disrupted gut microbiome in weight regain. The “signature” of a previous high-fat diet episode persists within the gut microbiome, even after weight loss, leading to reduced microbial diversity and future weight rebound.

A recent study sheds light on a different component of weight regain, suggesting that both human and mouse adipose tissues retain cellular transcriptional changes after weight loss.

The study explained “how an obesogenic memory is maintained in cells on a molecular level,” lead author Laura Hinte, PhD, a postdoctoral researcher in metabolism and obesity at ETH Zurich, in Zurich, Switzerland, told Medscape Medical News.

This cellular memory “may be linked to the ‘yo-yo effect’ because the fat cells ‘remember’ their prior obese state and likely aim to return to it. This means that one would have to ‘fight’ this obesogenic memory to maintain body weight.” 

The Unclear Health Implications of Weight Cycling

Repeated weight cycling has been associated with sarcopenia, increased risk of developing hypertension, poorer metabolic markers, myocardial infarction and stroke, hyperinsulinemia, decreased immune function, and higher all-cause mortality. Another study found that body composition after weight regain favored gain in fat mass, but no regain in fat-free mass.

Despite these reported associations, the overall body of research linking weight cycling to long-term health risks is decidedly mixed. A review of 23 studies comparing subjects with and without a history of weight cycling reported that the “overwhelming majority of evidence” suggested that weight cycling was not associated with any adverse effects in body weight, body composition, or metabolic rate.

However, many of these studies have methodological flaws, including a lack of consistency around what constitutes weight cycling, in terms of weight lost and gained as well as the number of cycles patients go through.

Better to Lose and Regain Than Stay Obese?

Edward List, PhD, senior scientist, Edison Biotechnology Institute, Ohio University, Athens, Ohio, and colleagues sought to address the flaws of prior studies by adopting a more targeted approach. In a 2013 study, they compared three diets in mice: High-fat (HF), low-fat (LF), or cycled diet, in which the mice received 4 weeks of LF and 4 weeks of HF foods throughout their lives.

Cycling between the two diets resulted in “large fluctuations” in body weight and fat mass. However, the weight-cycled mice showed no significant difference in lifespan compared with their LF-fed counterparts, “despite being overweight and eating a HF diet half of their lives.” On the other hand, the HF-fed group did experience a significant decrease in lifespan compared with both the LF-fed controls and the cycled mice.

“We know it’s healthier to be lean throughout your life,” List commented. “But our study and subsequent research suggest it’s better to lose weight, even if you end up putting it back on than to remain obese.”

Sustained Weight Loss Begins in the Brain

Kyra Bobinet, MD, MPH, an adjunct faculty member of AIM lab, Stanford University School of Medicine, Palo Alto, California, told Medscape Medical News that the diet industry routinely fails patients by focusing on performance-based programs that don’t yield sustained long-term benefits.

A superior strategy, according to Bobinet, incorporates emerging data regarding the role of a region of the brain called the habenula in driving compulsive food intake or stress-induced palatable food consumption.

The habenula is the “locus of depression and anxiety, and also the area responsible for withdrawal symptoms from addictive substances,” Bobinet said. It’s “activated by perceptions of failure, disappointment, frustration, demoralization, learned helplessness, powerlessness, and self-blame.” Simply put, an overactivated habenula can impair dieters’ motivation to continue in their weight-loss efforts.

A study of 36 weight-cycling adults reported that many experienced shame and stigma following weight regain. With each subsequent attempt to lose weight, they engaged in increasingly extreme behaviors and disordered eating.

“Once they started yo-yo dieting, people temporarily felt pride for losing the weight, but later felt shame and like a failure when they regained the weight,” lead author Lynsey Romo, PhD, professor, Department of Communication, North Carolina State University, Raleigh, North Carolina, told Medscape Medical News.

The few participants who stopped weight cycling “had to completely reframe their attitudes toward food and exercise, avoid social media, and learn to be happy with themselves at any size,” Romo said.

Bobinet, author of the book Unstoppable Brain, feels that successful weight loss “requires working with the brain instead of against it.” Her research suggests that those successful at keeping off weight adopt an “iterative mindset” whereby, rather than setting goals to attain by certain dates, they instead experiment with small, sustainable changes like reducing soda consumption, adding spices to vegetables, or gradually increasing physical activity.

“This kept the habenula quiet and not activated, by searching for a new iteration, modifying it, and adjusting it,” said Bobinet.

“We know the brain has neuroplasticity. The more you repeat something, the more it becomes habitual.” 

Harnessing Nutrigenomics 

Franchell Hamilton, MD, a bariatric surgeon and founder of NeuroSwitch Weight Loss Institute, focuses on the overlap between neurology and genetics in helping patients combat regaining weight.

“There are areas of the brain that light up when certain processed foods are brought out. These are people’s addictions, and we don’t treat addiction with surgery,” she told Medscape Medical News.

This is because, as Hamilton noted, “overcoming addiction is a neurobehavioral process,” which requires rewiring activated reward pathways.

Certain genes make individuals more vulnerable to this type of addictive response, Hamilton said. For example, Hamilton and colleagues evaluated over 200 individuals who had undergone bariatric surgery but regained > 30% of the weight they had lost. Almost all were found to have the DRD4 gene — a variant of the genome related to compulsive eating behaviors.

To treat her patients, Hamilton draws on the emerging field of nutrigenomics, which encompasses “complex interactions among genotype, diet, lifestyle, and environment” and can yield “personalized nutritional recommendations for health and risk assessment” and for weight loss.

“People with mutations in dopaminergic genes often need an ‘excess’ of something to feel dopamine, such as food,” said Hamilton, who helps patients identify other sources of dopamine release, citing gardening, sky diving, or rock climbing as examples.

Hamilton asks her patients about the specific reward in a given food, such as soda. Is it the sweetness? The carbonation? The cold temperature? Or the caffeine, which is present in many popular sodas? 

“Then we discuss how to swap out low-calorie, healthier alternatives that meet those specific needs.”

Hamilton incorporates techniques from cognitive behavioral therapy and biofeedback to help people find ways of assessing their responses to the food in question.

“Over time, they can pass by a billboard advertising soda or a hamburger with fries and not have any type of palpable response because we’ve rewired the brain.” 

Maintaining Weight Loss by Building Muscle 

Weintraub emphasizes the importance of incorporating resistance or strength training into patients’ routine, as well as adequate protein intake, to preserve muscle mass.

“This can limit the proportion of total body weight loss that’s muscle and maximize the amount that’s fat and also help maintain bone density,” he said.

He also noted that he agrees with the Obesity Medicine Association’s 2022 Clinical Practice Statement, which states that, “The essential message is that while repeated ‘yo-yo dieting’ may have adverse health effects, attempts to achieve a healthy body weight should not be avoided for fear of less-than-optimal results.”

Hinte, Weintraub, List, Romo, and Hamilton reported no relevant financial relationships. Bobinet is the CEO and founder of Fresh Tri, a habit formation software that is free on the app stores.

Batya Swift Yasgur, MA, LSW is a freelance writer with a counseling practice in Teaneck, New Jersey. She is a regular contributor to numerous medical publications, including Medscape Medical News and WebMD, and is the author of several consumer-oriented health books, as well as Behind the Burqa: Our Lives in Afghanistan and How We Escaped to Freedom (the memoir of two brave Afghan sisters who told their story).