Scale Goes Up, Happiness Doesn't Go Down: Study Finds - Video

A recent study shows gaining weight generally does not reduce happiness. A decade's worth of data analyzed by a researcher in Germany found that weight gain does not negatively affect life satisfaction. In some instances, individuals who gained weight even reported small increases in happiness, regardless of gender or age, indicating that the psychological impact of weight may be less pronounced than previously assumed. Findings are published in the international

Journal of Applied Positive Psychology.

The study investigated the impact of overweight and obesity on happiness, utilizing large-scale German panel data of 8815 individuals collected across ten survey waves. The participants were aged between 25 and 60 and the data was collected from 2011 to 2021. The study excluded individuals who were underweight or extremely obese to ensure results were not biased by outliers.

Body mass index (BMI), calculated from self-reported weight and height, served as the measure of overweight and obesity. Happiness was assessed using a single-item question about life satisfaction, rated on a scale from 0 (completely dissatisfied) to 10 (completely satisfied). Control variables included age, health, employment status, relationship status, and geographic region.

Although descriptive analyses initially showed a slight negative correlation between BMI and happiness, this relationship disappeared—or even reversed—when examining causal effects. Specifically, weight gain was not linked to a decrease in happiness. For both men and women, an increase in BMI was either unrelated to happiness or had a slight positive impact. These findings were consistent across all age groups and BMI categories, including those who were overweight or moderately obese.

“Not being able to detect any negative effects of overweight or obesity on happiness was very surprising to me, but the results are very robust and not a single analysis or model could find any negative effect in a longitudinal setting,” said Felix Bittmann, author of the study.

“Perhaps being overweight has a negative impact on satisfaction, but then possibly only for a short time, until people have become accustomed to the weight,” Bittmann said. “To measure these small and short-term effects, you would have to survey people much more often, which is costly.”

Reference: Bittmann, F. The Scale Goes Up, the Joy Goes Down? Investigating the Causal Effect of Body Weight on Happiness. Int J Appl Posit Psychol 10, 7 (2025). https://doi.org/10.1007/s41042-024-00203-z