Regular fluctuations in weight can add strain to the heart or lead to heightened inflammation. Yo-yo dieting, characterized by the cycle of losing and regaining weight, is known to stress the heart, according to experts.
Main Points:
- Individuals who repeatedly lost and regained weight over time faced a greater risk of heart attack, stroke, and heart disease-related death.
- Larger weight fluctuations posed a higher risk compared to smaller fluctuations.
- Weight cycling due to taking or stopping GLP-1 drugs like Ozempic was not observed in the study.
Individuals who repeatedly lose weight and then regain it, a phenomenon commonly referred to as weight cycling or yo-yo dieting, were significantly more prone to negative cardiovascular events such as heart attacks and strokes, irrespective of other cardiac risk factors and average overall weight, according to a study published on March 21 in JAMA Network Open.
“Our findings indicate that on a population level, individuals with greater variability in BMI [body mass index] are at higher risk for adverse cardiovascular events as compared to others with less BMI variability,” said coauthor of the study, Zakaria Almuwaqqat, MD, MPH. He is a hospital medicine doctor and postdoctoral fellow in cardiovascular disease at Emory Healthcare in Atlanta.
Around 50% of Americans Are Into Weight Cycling
In 2020, roughly half of Americans attempted to shed pounds. However, experts believe that between 80 to 95 percent of those who diet and successfully lose weight end up regaining it.
These statistics contribute to a significant occurrence of weight cycling, affecting an estimated 20 to 55 percent of the population.
For individuals utilizing GLP-1 drugs like Wegovy or Zepbound for weight management, it seems that they can prevent weight regain as long as they remain on the medication. However, discontinuation of the drug leads to the return of lost weight.
The More Weight Lost and Gained, the Greater the Risk
The investigation utilized extensive data gathered from two substantial cohorts: the Million Veteran Program, encompassing over 92,000 U.S. veterans, and 65,000 individuals from the UK Biobank.
Among the veterans, with an average age of 57 and predominantly male (88%), the demographic makeup reflected a diverse spectrum: 10% Hispanic, 24% Black, and 65% white. Over an average span of 10 years, BMI measurements, with an average of 30, were recorded multiple times. To be eligible for inclusion, each participant required at least three BMI measurements.
Contrastingly, the UK Biobank cohort also averaged an age of 57 but had a significantly lower proportion of men (41.5%). All subjects were white, and the average BMI stood at 27, notably lower than that of the veteran group.
The study analyzed weight cycling by computing the average BMI across the study duration, facilitating the assessment of fluctuations. For instance, if a participant recorded BMI measurements of 30, 31, and 32, the resultant average would be 31, with a standard deviation of 1.
Over a follow-up period of approximately four years, researchers monitored incidences of heart attacks, strokes, and fatalities attributed to heart disease.
The findings revealed a notable correlation between weight cycling and heightened risk of adverse cardiovascular outcomes across all racial and ethnic groups. Within the veteran cohort, each 1 standard deviation increase in BMI variability correlated with a 16% elevation in cardiovascular event risk, encompassing nonfatal heart attacks, strokes, and deaths from heart disease.
Similarly, in the UK Biobank cohort, each 1 standard deviation increase in BMI variability correlated with an 8% escalation in the risk of cardiovascular-related mortality.
“We have found that the greater change in BMI correlates with a higher risk of adverse cardiovascular events in a dose-dependent manner,” Dr. Almuwaqqat said.
Nishant Shah, MD, a cardiologist at Duke Health in Durham, North Carolina, who was not involved in the study, explains that since the study utilized each subject’s specific weight to calculate the standard deviation, it becomes challenging to determine the precise level of weight fluctuation deemed high risk. This is because it varies greatly among individual patients.
“Instead, consider rapid shifts over a course of time — for example, down 20 pounds from baseline and then up 20 pounds from baseline over a six month period — to be of more cardiovascular risk than a sustained 20 pound weight loss, according to the study results,” he said.
Risk Impacted by Race and Ethnicity
Researchers discovered that the risk associated with weight cycling varied based on race and ethnicity. They observed a stronger connection between weight cycling and stroke among Black participants, while the link between weight cycling and cardiovascular death was more pronounced in white subjects. Interestingly, the association wasn’t as robust in the UK group, prompting the authors to suggest that factors such as race or sex might influence these risks. This highlights the complexity of how different demographic factors can interact with health outcomes.
The Extra Stress Added to the Heart
These findings validate prior research, such as a study from November 2018 that tracked over 3,000 individuals with obesity for 16 years. It revealed that weight cycling was linked to an increased risk of mortality.
It’s not really clear why weight cycling may increase the risk of heart disease, Dr. Shah stated. “There are many hypotheses. For instance, the rapid changes in body weight can add extra stress to the heart, may lead to vascular dysfunction, or lead to more inflammatory fatty tissue development,” he said.
Shah suggests that sudden fluctuations in weight could also stem from other medical issues such as cancers, infections, or inflammatory disorders. This could exacerbate stress, especially for individuals with pre-existing heart conditions.
Working Hard to Achieve Healthy Weight Provides Health Benefits Still
The findings doesn’t also imply that you should abandon your efforts to achieve healthy weight, Shah said. “There are plenty of benefits of weight loss, and people should still strive to find ways they can successfully have sustainable weight loss,” he said.
He highlights that obesity can result in various serious comorbidities, such as high blood pressure, high cholesterol, and type 2 diabetes, all of which can escalate your risk of heart disease.
“It is also very difficult to make many conclusions based on one study alone. We need more data to better understand the magnitude of BMI variability that is most concerning,” he said.
Shah points out that there was a significantly higher proportion of males than females in the veterans’ cohort. Additionally, there might have been other risks or contributing factors that the researchers didn’t consider, which could have influenced the findings.
Should Findings Worry Those Taking GLP-1 Off and On?
Almuwaqqat notes that this study didn’t include individuals on GLP-1s. Since the participants experienced BMI changes not attributed to medications, this question cannot be addressed with this data.
“The use of GLP-1 is generally associated with cardiovascular risk reduction, and the impact of weight fluctuations is not clear among these individuals,” he said.
GLP-1 medications have several benefits when they are prescribed and taken appropriately, says Shah. “At the end of the day it is a benefit-to-risk evaluation that is very specific to the patient. Patients should discuss with their healthcare provider about what is right for them,” he said.
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