March 4, 2014
Stress and anxiety are both significant mental health conditions in this country, and work-related stress is a growing problem. The Victorian Job Stress Survey found high rates of job strain in both men and women, 26% and 19% respectively. Prolonged exposure to stress and anxiety can be catastrophic by contributing to the development of conditions such as metabolic syndrome, depression and obesity. Dr Susan Torres, Senior Lecturer in the area of dietary intake and mental health from the School of Exercise and Nutrition Sciences, explores this topic further.
One possible way that stress may be contributing to our current obesity epidemic is by affecting food consumption. Studies in animals can give us a convenient way to measure the effect of stress on food intake. Mild stress induced by pinching the tails of rats leads to an increase in food intake, but only when highly palatable foods are offered. However, a more severe stressor, immobilisation, reduces food intake in rats.
In humans, there are difficulties in trying to determine the effect of stress on food intake. We can induce stress in a laboratory setting, but this may not mimic real life stress. In a real life setting, people who are under greater work pressure report increases in total energy and fat intake compared with times of reduced work pressure.
Stress appears to increase food intake, particularly the more highly palatable foods that are high in sugar and fat. In a longitudinal study, elevated levels of stress at baseline predicted a weight gain of 10 kg over a period 6 years in men.
Responses to chronic stress, for example work stress, results in the release of the hormone cortisol which may drive appetite for high-fat sweet foods. We must consider that this increase in energy and fat intake during periods of life stress may be unrelated to stress or anxiety, but rather due to insufficient time to purchase and prepare foods and over reliance of convenience foods which are typically high in sugar and fat.
Dr Susan Torres
School of Exercise and Nutrition Sciences, Deakin University