Does Teenage Stress Cause Weight Gain?Wednesday, December 16, 2009
This question was addressed by Cornelia van Jaarsveld and colleagues from University College London, UK, in a paper just published in OBESITY.
Prospective associations between perceived stress and changes in waist circumference and BMI were examined in data from the Health and Behaviour in Teenagers Study (HABITS), in which height, weight, and waist circumference were measured annually in 4,065 adolescents aged from 11 to 16.
In contrast to their expectations, the researchers found that perceived stress in any year was not related prospectively to increases in waist or BMI 1-4 years later, nor was there any evidence that higher stress over the whole period was associated with greater gains in waist or BMI.
However, waist and BMI were significantly higher in the moderate- and higher-stress groups than the lower-stress group across the whole 5-year period. Also, persistent stress was associated with higher waist circumference and BMI in adolescence, but did not lead to differential changes over 5 years.
This study clearly suggests that the relationship between stress and obesity is more complicated than generally assumed – clearly increased perceived stress does not translate directly into greater weight gain.
The authors suggest several reasons for why this relationship may be more complex:
1) Stress can both increase and decrease appetite – thus some people may eat more when stressed, others may stop eating – at a population level this phenomenon can balance out some of the weight risk associated with increased stress levels.
2) Increased weight may result in compensatory behaviours, so that although stress is causing some people to eat more, these people are also more likely to engage in dieting or exercise to manage their weight.
3) Stress may set weight trajectories early in life (e.g. by changing the neural circuitry in their hypothalamus). so that by the time kids reach adolescence (as in this study), their current level of stress may no longer determine or predict their weight status.
Thus, in summary, although the study shows that adolescents with higher perceived stress levels tend to be heavier, their current stress levels did not affect their rate of weight gain during the observation period. The authors (and so do I) tend to favor explanation 3 for their findings – this would mean that high stress levels in younger children may translate into greater teenage (and adult?) obesity.