There is a stronger connection between stress and weight gain in American black girls than American white girls.

Although dealing with large amounts of stress for a period of 10 years predicts greater increases in body weight for both white and black girls, the experience of chronic stress appears to have a larger negative impact on the weight of black girls.

This finding, published in Annals of Behavioral Medicine may explain racial disparities in obesity levels.

The prevalence of obesity in black populations in the United States is 50% higher than in those of whites. This contrast is seen as early as childhood, and especially in the teenage years of females.

Ethnic minorities suffer from a great deal of psychological stress, more than whites, partly due to perceived racial discrimination.

Scientists have known that stress is associated with a higher change of depression, heart disease and infectious diseases. One particular study in Proceedings of the National Academy of Sciences found that chronic psychological stress is associated with the body losing its ability to regulate the inflammatory response, which can promote the development and progression of disease.

In this current study, over a period of ten years, the experience of chronic stress in young girls was examined to determine whether it had an influence on their BMI (body mass index), and whether the same effect was seen in both white and black adolescents.

Data from the National Heart, Lung and Blood Institute’s (NHLBI) Growth and Health Study was gathered and analyzed, in order to assess the prevalence of obesity in 2,379 black and white girls. The girls were observed at age 10 and then followed up for 10 years. Experiences of psychological stress were closely observed.

By the end of the study, the team, led by Dr. Tomiyama of the University of California, Los Angeles, discovered that white girls reported more stress, but more black girls were overweight or obese.

Both groups saw an increase in their weight if their level of chronic stress was increasing. However, the effect of chronic stress was stronger for black girls, even though they reported less stress overall.

For example, black females with one unit increase in stress, led to 0.8 BMI unit increase every two years, while their counterparts with one unit of stress led to 0.55 BMI unit increase.

The authors wrote:

“Our study documents a relationship between chronic perceived stress and BMI over a decade of growth in black and white girls. However, the relationship between perceived stress and BMI is stronger in black girls. Psychological stress may lead to weight gain through behavioral pathways, such as increased food consumption and sedentary lifestyles, but also directly through prolonged exposure to biological stress mediators such as cortisol.”

The research pointed out that stress may be playing a significant role in the obesity epidemic, while also contributing to racial disparities at the same time.

Written by Sarah Glynn