Many people will report to us that they gained weight because of “stress eating.” They binged in times of worry. Some people tell us that they gained weight and really did not increase their caloric intake. How is that possible? In this article we will address the question: “How does stress make you gain weight?”
The concept of this article is that stress will create a bad environment in your gut that can cause you to crave (stress eat) more bad foods that can lead to the rise of bad bacteria in your gut. Those bad bacteria then will send distorted messages to your brain that will make your stress worse and lead you to depression.
We are going to start our search for answers in a study (1) from doctors at Ohio State University. In this study these doctors suggested that women experiencing one or more stressful events can suffer from a slow down of their the body’s metabolism, potentially contributing to weight gain. How did they measure this? But giving them a meal the day after the study participants reported on the number of stressful events that they faced. The meal consisted 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 non-stressed 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
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.
When your gut tells you to eat bad foods you have a problem with stress
A follow up study in 2019 (2) suggested that “psychological stress and depression can promote consumption of highly palatable foods (stress eating bad foods), influencing which gut bacteria thrive. (Bad foods, bad bacteria). Additionally, stress and depression can reshape the gut bacteria’s composition through stress hormones, inflammation, and autonomic alterations (physiological changes). In turn, the gut bacteria release metabolites, toxins, and neurohormones that can alter eating behavior and mood. Some bacterial species may encourage dysregulated eating. (Bad bacteria makes you eat bad foods). The gut bacteria may also upregulate stress responsiveness and heighten the risk for depression, which probiotic supplementation may attenuate.”
What is being said here is that stress eating creates a new and bad situation in your gut. Your gut fills with bad bacteria that needs bad food to survive. The messages of the gut to the brain may include messages of depression and stress to make the brain “crave,” the bad foods the bad bacteria need. The study also mentions the possible benefits of probiotics.
In the medical journal of Reviews in the neurosciences (3) doctors writing in support of probiotics in helping patients with major depressive disorders wrote that the attention being given to probiotics stems from ineffective treatments currently being offered. “Despite intensified research efforts to improve the treatment options and remission rates in mood disorders, no disease modifying treatment exists for these disorders. Accumulating evidence implicates the involvement of the gut microbiota in processes relevant to etiopathology (the origins of) of central nervous system-based disorders. . . The concept of psychobiotics, which is bacterial-based interventions with mental health benefit, is emerging in the field.”
As mentioned, the concept of this article is that stress will create a bad environment in your gut that can cause you to crave (stress eat) more bad foods that can lead to the rise of bad bacteria in your gut. Those bad bacteria then will send distorted messages to your brain that will make your stress worse and lead you to depression.
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1 Kiecolt-Glaser JK, Habash DL, Fagundes CP, Andridge R, Peng J, Malarkey WB, Belury MA. Daily stressors, past depression, and metabolic responses to high-fat meals: a novel path to obesity. Biological psychiatry. 2015 Apr 1;77(7):653-60.
2 Madison A, Kiecolt-Glaser JK. Stress, depression, diet, and the gut microbiota: human–bacteria interactions at the core of psychoneuroimmunology and nutrition. Current opinion in behavioral sciences. 2019 Aug 1;28:105-10.
3 Rios AC, Maurya PK, Pedrini M, Zeni-Graiff M, Asevedo E, Mansur RB, Wieck A, Grassi-Oliveira R, McIntyre RS, Hayashi MA, Brietzke E. Microbiota abnormalities and the therapeutic potential of probiotics in the treatment of mood disorders. Reviews in the Neurosciences. 2017 May 8.