Depression May Cause Weight Gain for Some People, Study Finds

Periods of depression may lead to weight gain, but only in people who are already overweight or obese, new research reveals.

Symptoms of depression were linked to increased body weight a month later for overweight or obese individuals, a study in the journal PLOS ONE found, but there was no general link between depression and having a greater weight.

The findings were revealed by researchers at Cambridge University's Medical Research Council (MRC) Epidemiology Unit, who examined data from over 2,000 British adults who answered questions every month for nine months during the COVID-19 pandemic. These questions included queries about mental well-being, including depression and anxiety, and about body weight.

"We found that for every increment increase in an individual's usual score for depressive symptoms, their subsequent weight one month later increased by 45g (0.1 pounds)," Julia Mueller, study co-author and MRC Epidemiology Unit researcher, told Newsweek. "

This may seem small but would mean, for example, that in an individual whose depressive symptoms score rose from five to 10 (equal to an increase from 'mild' to 'moderate' depressive symptoms), it would relate to an average weight gain of 225g (0.5 pounds)."

This effect was only observed in overweight and obese participants. Overweight is defined as having a body mass index of between 25 and 29.9, and obese is defined as a BMI of over 30.

"[Overweight] individuals had on average an increase of 52g (0.11 pounds) for each increment point increase from their usual depressive symptoms score, and for those with obesity, the comparable weight gain was 71g (0.16 pounds)," Mueller said.

This suggests that people who are overweight or obese may be much more vulnerable to gaining weight when they feel more depressed than others. It is unclear if this effect came as a result of the participants eating more due to their depression or another depression-driven cause of weight gain.

"In this study, we did not examine the role of diet," Mueller said. "Previous evidence suggests that people may gain weight during emotionally difficult times for a variety of reasons, including changes in diet, exercising less, sleeping less well, or because negative emotions may lead to metabolic changes that promote abdominal fat deposition. Based on our findings we can't determine what the causal pathway was, but it is likely a combination of these various factors."

The authors hope that these findings can be used to ensure that overweight and obese people are given appropriate care during periods of depression.

"Although the weight gain was relatively small, even small weight changes occurring over short periods of time can lead to larger weight changes in the long-term, particularly among those with overweight and obesity. People with a high BMI are already at greater risk from other health conditions, so this could potentially lead to a further deterioration in their health," Mueller said.

"Monitoring and addressing depressive symptoms in individuals overweight or with obesity could help prevent further weight gain and be beneficial to both their mental and physical health."

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about depression and weight gain? Let us know via science@newsweek.com.