Stress makes you fat. This is not only because people tend to eat less healthily when they are under stress, but also because stress reduces your body’s energy burning capacity. Researchers at Ohio State University in the US published an article about this in Biological Psychiatry. The boss from hell, girlfriend problems, or a DIY neighbour with a hammer drill: all can reduce your daily energy expenditure by 100 kcal.
The researchers gave 58 women – average age 53 – meals consisting of 60 g fat, 59 g carbohydrates and 36 g protein. After the meal the researchers monitored the women’s blood and energy expenditure for six hours.
Over half of the women were breast cancer survivors, who you’d therefore expect to be under more stress than other women. The researchers used questionnaires to determine to what extent this was the case.
The women’s calorie expenditure [REE] was high after eating the meal, but decreased as the hours passed.
The reduction in energy expenditure was faster in the women who said that they’d been troubled by stress the day before. Stress included an argument at work or home, or something more serious.
After the meal the women’s fat burning [Fat Oxidation] increased gradually. But this increase was less fast in the women with a stress factor in their lives.
The women under stress had higher levels of triglycerides [fats] in their blood after eating. This would also indicate that the body has more difficult using fat as a fuel under stressful conditions.
“This study provides novel evidence of metabolic pathways through which prior day stressors and past depression facilitate weight gain over time”, the researchers summarise.
“Greater numbers of prior day stressors were associated with decreased postmeal energy expenditure. The cumulative difference between one recent stressor and no stressors over 6 hours translates into 435 kJ, averaged across meal type and group and all controlling variables. This difference would add up to almost 11 pounds [5 kg] across a year.”