Eat healthy — it’s a common refrain these days, everywhere we turn. And certainly healthful eating has many well-established benefits. But there’s a new twist: Stress can override those benefits.
A pair of recent studies suggests that a healthy diet can’t combat the negative effects of stress on mind, body and soul. In the first study, women participated in a “meal challenge” in which they were each given two types of meals to eat, on different days. They received either a meal that was high in unhealthy saturated fat or a meal high in the healthier plant-based, high oleic sunflower oil (Kiecolt-Glaser et al, 2016).
Depression, stress and diet are all known to affect inflammation, so researchers measured several common inflammation markers such as C-reactive protein (CRP). Higher inflammation levels are linked to an increased lifetime risk of serious diseases, such as cardiovascular disease, type 2 diabetes, arthritis, and some cancers.
The results showed that women who received the healthier meal and were not stressed showed lower inflammatory responses than when they received the high saturated fat meal. No surprise there. But here’s the part that may seem counterintuitive at first…
When women were stressed on the day they ate the healthy meal, their inflammation responses were as high as they would have been if they had eaten the saturated fat meal! In other words, the healthy meal didn’t have the expected positive impact on inflammation. The meal-related differences disappeared.
“Stress seemed to boost inflammation,” explains study author Janice Kiecolt-Glaser, director of the Institute for Behavioral Medicine Research at the Ohio State University. Kiecolt-Glaser’s prior research had also shown that the wounds of people who are stressed heal more slowly.
Now, perhaps you’re thinking, “Well, these poor women must have been dealing with off-the-charts stress…” But no. They weren’t experiencing life-threatening stressors; rather they were experiencing the typical stressful events many of us might face on any given day (e.g., child care problems).
The study also found that women with a history of Major Depression had higher post-meal blood pressure than those with no history of depression, demonstrating that recent stressors and/or a history of depression can alter metabolism, which promotes inflammation and atherogenesis (part of the disease process of arteriosclerosis or “hardening of the arteries”).
Stress paves a path to obesity
Unfortunately, it gets worse. Another study by Kiecolt-Glaser and colleagues showed that not only can stress and depression annihilate our best efforts to eat healthfully, they may actually help pave the path to obesity and obesity-related diseases. The study found that stress promotes weight gain in women by altering metabolism and slowing calorie-burning (Kiecolt-Glaser et al, 2015).
The study assessed the impact of the women’s daily stressors and past depression on metabolic responses to two different meals. Participants again received either a meal high in saturated fat or a meal high in the healthier oleic sunflower oil. Before and after the two meals, researchers assessed resting energy expenditure (REE), fat and carbohydrate oxidation, triglycerides, cortisol, insulin and glucose.
The study showed how stress and depression alter metabolic responses to high-fat meals in ways that promote obesity. They found that both stressors on the prior day and a history of depression were associated with lower post-meal energy expenditure and fat oxidation, as well as heightened post-meal triglycerides, cortisol, and insulin. The greater the number of stressors the lower the post-meal resting energy expenditure, fat oxidation, and the higher the insulin levels.
What causes these negative changes in metabolism?
Well, we all know that maintaining a healthy long-term weight or energy balance requires that caloric intake equals calories burned. Resting energy expenditure plays a key role in energy balance and weight control, accounting for 65% to 75% of our total daily energy expenditure (Lara et al, 2010). Thus, lower daily energy expenditure increases the risk for weight gain and obesity. In addition, metabolism of macronutrients, primarily fats and carbohydrates, also influences weight regulation (Flatt, 2012), and, over time, lower fat oxidation rate facilitates weight gain (Blaak et al, 2006).
Psychological stressors provoke multiple metabolic changes including alterations in energy expenditure as well as fat, carbohydrate, and protein metabolism. Depression and stressful events — both separately and together —can alter neurochemistry, neurobiology, and behavior, providing multiple pathways for metabolic alterations. For example, both depression and stress elevate cortisol production. Higher cortisol fosters increased intake of calorie-dense “comfort” foods, and insulin secretion rises as cortisol increases (Dallman et al, 2010). Persistent high cortisol and insulin levels increase visceral fat accumulation (Dallman et al, 2010).
Depression makes people more vulnerable to stressors; in fact, people with a history of depression experience more events as stressful than those with no history of depression. Past depression can also boost emotional reactivity to daily stressors (Hammen, 1991; Huskey et al, 2009).
The 11-pound gain
The study found that the cumulative 6-hour difference between one prior day stressor and no stressors translated into 104 kcal, a difference that could result in weight gain of almost 11 pounds per year. Multiply 11 additional pounds per year times several years and… well, you get the picture: a path to obesity.
Clearly, eating healthfully isn’t enough to maintain goal weight. The key is to boost our resilience to stressors so that they don’t have negative effects on us. Stress relief is a gateway benefit of Sahaja meditation. Not only this, but Sahaja meditation can also have an impact on weight loss in other direct ways.
Blaak, E.E., Hul, G., Verdich, C., Stich, V., Martinez, A., Petersen, M., et al. Fat oxidation before and after a high fat load in the obese insulin-resistant state. J Clin Endocrinol Metab. 2006;91:1462–1469.
Dallman, M.F.. Stress-induced obesity and the emotional nervous system. Trends Endocrinol Metab. 2010; 21:159–165.
Flatt, J.P.. Misconceptions in body weight regulation: Implications for the obesity pandemic. Crit Rev Clin Lab Sci. 2012;49:150–165.
Hammen C. Generation of stress in the course of unipolar depression. J Abnorm Psychol. 1991;100:555–561.
Husky M, Mazure C, Maciejewski P, Swendsen J. Past depression and gender interact to influence emotional reactivity to daily life stress. Cognit Ther Res. 2009;33:264–271.
Kiecolt-Glaser, J.K., Habash, D.L., Fagundes C.P., Andridge, R., Peng, J., Malarkey, W,B., Belury, M.A. Daily stressors, past depression, and metabolic responses to high-fat meals: a novel path to obesity. Biol Psychiatry. 2015 Apr 1;77(7):653-60.
Kiecolt-Glaser, J.K., Fagundes, C.P., Andridge, R., Peng, J., Malarkey, W.B., Habash, D.L., Belury, M.A. Depression, daily stressors and inflammatory responses to high-fat meals: when stress overrides healthier food choices. Molecular Psychiatry , (20 September 2016).
Lara J, Taylor, M.A., Macdonald, I.A.. Clinical obesity in adults and children. Third ed. Wiley-Blackwell; 2010. Energy expenditure in humans: The influence of activity, diet and the sympathetic nervous system; pp. 151–163.