Mental Health and Obesity: A Meta-Analysis

The relationship between obesity and psychological distress is not clear because research conducted so far is not conclusive, with some studies finding that obese people report less mental health than normal-weight individuals, whilst others find that obesity may work as a protective factor that prevents people with weight problems from developing mental health issues. In this meta-analysis we review research that compares the mental health (measured with SF-36) of class I obese people (Body Mass Index between 30 and 34.99) with normal weight people (Body Mass Index between 18 and 24.99) in non-clinical adult populations. The meta-analysis conducted assumed a random-effects model and a weighted mean effect size was calculated (d), together with its statistical significance and confidence interval. Results reveal that obese women report less mental health than normal weight females (d = -.26) but that obese men show more mental health than normal weight individuals (d = .62). The results give support to the so-called Jolly Fat hypothesis.