“Lather, rinse, repeat,” the shampoo bottle tells us. Following these instructions, we would never get out of the shower, never get to the business of living our lives. “Lather, rinse, repeat,” I often think to myself as I ask patients about their history of dieting and weight change.
About half of all Americans report that they are trying to lose weight. For many, the sum total of these efforts will be, “lose weight, gain weight, repeat.” In my experience, following this pattern prevents some people from getting to the business of living their lives.
Yo-yo dieting and the weight cycling that results sometimes plunges people into psychological despair. It can lead to an over-emphasis on body shape or weight for self-esteem, and for a subset of the population, can activate eating disordered thought and behavior patterns such as rigid food rules, guilt about eating, and binge eating.
The changes in weight and eating behavior seen in people with eating disorders also affect physical health, including heart health. A study recently published in the New England Journal of Medicine, titled “Body Weight Fluctuations and Outcomes in Coronary Disease,” examined some concerning associations between weight cycling, heart disease and death. Though this was a study of adults with heart problems, not eating disorders, it offers some helpful reminders about the hazards of yo-yo dieting.
This study was a post-hoc analysis from the Treating New Targets Trial, which means that the authors used data from a concluded study to ask additional questions and look for patterns. The original study was a randomized controlled medication trial in over 10,000 patients between the ages of 35 and 75 with coronary artery disease, high cholesterol levels, and some history of heart problems.
In the current study, researchers analyzed weight data of 9,509 men and women who participated in the larger medication trial. Monitored for nearly five years, participants were weighed every three months for the first year of the study and then every six months for the subsequent years. Researchers calculated a complicated index of body weight variability based on participants’ fluctuations in body weight from one study visit to the next.
Outcomes in coronary disease included the occurrence of any of a range of heart problems or cardiovascular “events” (such as heart attack, stroke, or death).
In this study of patients with heart disease, controlling for traditional risk factors, higher body weight variability –yo-yoing back and forth with weight gain and loss—was associated with greater risk of:
- Coronary artery disease
- Cardiovascular events
For patients in the top fifth of body weight variability (those with the greatest weight fluctuations), the risk of coronary disease was 64% higher, the risk of cardiovascular events was 85% higher, and the risk of death was 124% higher than those in the bottom fifth of body weight variability.
An important caveat to these findings is that baseline weight mattered. For those who were overweight or obese at the study’s start, shifts in body weight were associated with higher rates of heart problems and mortality. This association was absent for individuals with normal body weight at baseline (even if they experienced subsequent weight fluctuations).
What Does It All Mean?
The current study clarifies that for overweight or obese people with heart disease, rapidly losing and regaining weight increases the likelihood of additional heart problems, heart attack, stroke, and death.
Taken together, these findings reinforce the importance of:
- Setting reasonable, incremental, and sustainable goals for lifestyle change rather than falling for the latest fad diet
- Identifying multiple markers of health as indicators of success with a behavior change plan (e.g., cholesterol level, blood pressure, etc.)
- Thoughtfully establishing an achievable, sustainable target weight if weight is among those indicators
Equally important: What does it not mean? Correlational research can be tricky to interpret. As the study authors remind us, associations do not necessarily indicate a cause-and-effect relationship between weight fluctuations, coronary disease and mortality. Future investigations of causation, though difficult to carry out, are vital to more fully answering our questions about the risks of weight cycling.