New research shows link between weight loss strategies and depression risk

A new study suggests that the way people attempt to lose weight might have a meaningful impact on their mental health. The research, published in the Journal of Affective Disorders, showed that healthy weight loss behaviors such as eating more fruits and vegetables, switching to lower-calorie foods, and exercising were associated with fewer symptoms of depression. In contrast, unhealthy approaches—including skipping meals, taking diet pills, or vomiting—were linked to a higher likelihood of depressive symptoms.

The researchers conducted this study to better understand how weight loss efforts relate to psychological well-being. As weight loss behaviors become more widespread, concerns have grown about the mental health consequences of certain practices. While strategies like improving diet and increasing physical activity are often encouraged, many people turn to more extreme methods that could be emotionally harmful. The team sought to evaluate how various strategies impact depressive symptoms, especially given the growing popularity of weight loss efforts in both clinical and non-clinical settings.

“The growing concern over the global obesity epidemic and its associated health risks, including mental health implications, motivated me to explore the potential link between weight loss methods and depression. Given the increasing prevalence of both obesity and depression, understanding how different weight loss methods affect mental well-being is crucial for public health,” explained study author Zheng Zhang, a PhD candidate at South China Normal University.

To investigate, the researchers used data from the National Health and Nutrition Examination Survey, a large, ongoing study of health trends in the United States. They analyzed responses from 9,334 non-pregnant adults aged 20 to 79 who had attempted to lose weight in the past year. About 61% of the participants were women, and the average age was 47. Participants were asked to report on their weight loss behaviors and completed a standardized questionnaire assessing depressive symptoms over the previous two weeks.

Weight loss strategies were divided into two categories. Protective methods included exercising, switching to lower-calorie foods, and increasing fruit and vegetable intake. Harmful methods included skipping meals, using liquid diet formulas, taking prescription or over-the-counter diet pills, and inducing vomiting or using laxatives. The researchers used statistical models to assess how these behaviors were associated with depressive symptoms while accounting for other factors like age, income, education, smoking status, and body mass index.

The researchers found that people who reported using protective strategies were significantly less likely to experience depressive symptoms. Exercise, for example, was associated with a 39% reduction in the likelihood of depression, while eating more fruits and vegetables was linked to a 22% reduction. On the other hand, participants who engaged in harmful strategies had a substantially higher risk of depressive symptoms. Skipping meals was linked to a 71% increase in depression risk, and those who reported vomiting or using laxatives had more than twice the odds of experiencing depression.

The number of strategies used also mattered. People who used more protective strategies tended to report fewer symptoms of depression, while those who used multiple harmful strategies were at a significantly greater risk. Those who employed three or more harmful methods had nearly triple the odds of reporting depressive symptoms compared to those who used none.

“One finding that stood out was the significant difference in depression risk between individuals who lost weight through diet and exercise compared to those who used surgical or pharmaceutical methods,” Zhang told PsyPost. “This suggests that the long-term psychological benefits of more sustainable weight loss methods, like lifestyle changes, might be more favorable.”

The researchers also explored how these effects varied by demographic factors. Protective strategies were especially beneficial for individuals who were already at higher risk of depression, such as women, people with lower education levels, and those living in poverty. Harmful strategies, by contrast, were particularly linked to increased depressive symptoms among younger people, men, and those without chronic health conditions. These findings suggest that both vulnerable and advantaged groups may need tailored guidance when it comes to weight loss and mental health.

Importantly, the emotional effects of weight loss behaviors appeared to be more pronounced in individuals who failed to lose weight. For example, people who used extreme strategies but did not successfully reduce their body weight reported higher levels of depressive symptoms, suggesting that the combination of unsuccessful outcomes and harmful methods may contribute to emotional distress.

“Our study highlights that weight loss methods, especially those that focus on lifestyle changes such as diet and physical activity, can have varying impacts on mental health,” Zhang explained. “It’s essential for individuals to approach weight loss with a holistic mindset, considering not only the physical but also the psychological aspects of these methods.”

While the study highlights key patterns, it does have limitations. Because the data are cross-sectional, the researchers cannot determine whether the weight loss behaviors caused changes in depressive symptoms or if people with more symptoms were more likely to choose certain strategies. In addition, all information was self-reported, which can introduce biases related to memory or social desirability.

“The cross-sectional nature of the NHANES data prevents us from drawing causal conclusions, and we acknowledge that other factors such as socioeconomic status and pre-existing mental health conditions could influence our findings,” Zhang noted.

“In the future, I aim to explore more deeply how different weight loss interventions impact mental health in diverse populations. This could help inform personalized treatment plans and public health recommendations to support both physical and psychological well-being.”

“I believe that our research underscores the need for a more integrated approach to weight loss and mental health,” Zhang added. “It’s essential to not only focus on achieving weight loss goals but also to prioritize mental health outcomes when choosing weight loss methods.”

The study, “Weight loss methods and risk of depression: Evidence from the NHANES 2005-2018 cohort,” was authored by Huijie Xu, Zheng Zhang, and Yuanyuan Wang.