Why stress makes you gain weightAugust 25, 2016 August 25, 2016
Doctors at Ohio State University say that women experiencing one or more stressful events the day before eating a single high-fat meal can slow the body’s metabolism, potentially contributing to weight gain.
The Ohio State University (OSU) researchers questioned study participants about the previous day’s stressors before giving them a meal consisting of 930 calories and 60 grams of fat. The scientists then measured their metabolic rate – how long it took the women to burn calories and fat – and took measures of blood sugar, triglycerides, insulin and the stress hormone cortisol.
- On average, the women in the study who reported one or more stressors during the previous 24 hours burned 104 fewer calories than nonstressed women in the seven hours after eating the high-fat meal – a difference that could result in weight gain of almost 11 pounds in one year.
- The stressed women also had higher levels of insulin, which contributes to the storage of fat, and less fat oxidation – the conversion of large fat molecules into smaller molecules that can be used as fuel. Fat that is not burned is stored.
“This means that, over time, stressors could lead to weight gain,” said Jan Kiecolt-Glaser, professor of psychiatry and psychology at The Ohio State University and lead author of the study. “We know from other data that we’re more likely to eat the wrong foods when we’re stressed, and our data say that when we eat the wrong foods, weight gain becomes more likely because we are burning fewer calories.”
Previous research also has shown that people who experience stress and other mood disruptions are at higher risk of becoming overweight or obese
Previous research also has shown that people who experience stress and other mood disruptions are at higher risk of becoming overweight or obese. This study, the researchers say, appears to illustrate at least one mechanism behind that connection.
The study was conducted in 58 women, average age 53, and included two admissions to Ohio State’s Clinical Research Center for daylong analyses. To regulate their food intake for 24 hours before eating the high-fat meal, researchers supplied the participants with three standardized meals on the previous day and instructed them to fast for 12 hours before reporting for their study visit.
On the day of admission, the participants completed several questionnaires to assess their depressive symptoms and physical activity and were interviewed about stressful events on the prior day. Thirty-one women reported at least one prior day stressor on one visit and 21 reported stressors at both visits. Six women reported no stressors.
Most of the reported stressors were interpersonal in nature:
- arguments with co-workers or spouses,
- disagreements with friends,
- trouble with children or
- work-related pressures.
The research meal consisted of eggs, turkey sausage, biscuits and gravy – roughly equivalent in calories and fat to a loaded two-patty hamburger and French fries at a fast-food restaurant. Participants were required to eat the entire meal within 20 minutes.
The control for comparison in this randomized trial was that one meal contained saturated fat and another was high in a different kind of fat: sunflower oil containing monounsaturated fat, which is associated with a variety of health benefits.
Before the meal, participants rested for 30 minutes and their energy expenditure – or calories burned by converting food to energy – was tested during that time. After they ate their meal, their metabolic rate was tested for 20 minutes of every hour for the next seven hours. Researchers obtained this data by using equipment that measured inhaled and exhaled airflow of oxygen and carbon dioxide.
- The stressors’ effects of increasing insulin had a time element: Insulin spiked soon after the high-fat meal was consumed and then decreased to roughly match insulin levels in nonstressed women after another 90 minutes.
- A history of depression alone did not affect metabolic rate, but depression combined with previous stressors led to a steeper immediate rise in triglycerides after the meal. Triglycerides are a form of fat in the blood, and high levels are considered a risk for cardiovascular disease. 1
Stress from the Job
People with job stress and an unhealthy lifestyle are at higher risk of coronary artery disease than people who have job stress but lead healthy lifestyles, found a study published in CMAJ (Canadian Medical Association Journal).
To determine whether a healthy lifestyle can help reduce the effects of job stress on coronary artery disease, researchers looked at 7 cohort studies from a large European initiative that included over 100,000 people.
Of the total participants, 15 986 (16%) reported job stress, which was determined from specific job-related questions in the studies. The investigators defined three lifestyle categories based on smoking, alcohol consumption, physical activity/inactivity and obesity (body mass index). A “healthy lifestyle” had no lifestyle risk factors, “moderately unhealthy lifestyle” had one risk factor and “unhealthy lifestyle” included 2-4 lifestyle risk factors.
- A total of 1086 participants had incident events of coronary artery disease events during the follow-up period. The 10-year incidence of coronary artery disease was 18.4 per 1000 people for people with job strain and 14.7 for those without job strain.
- People with an unhealthy lifestyle had a significantly higher 10-year incidence rate (30.6 per 1000) compared to those with a healthy lifestyle (12.0 per 1000). The incidence rate was 31.2 per 1000 for participants with job strain and an unhealthy lifestyle but only 14.7 for those with job strain and a healthy lifestyle.
Evidence from randomized controlled trials has shown that lifestyle changes such as weight loss and stopping smoking can reduce the risk of disease.