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Stress Less, Weigh Less? Cortisol’s Role in Our Diet

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There’s been a lot of buzz about the role that cortisol, which increases in response to elevated physical and mental stress, plays in weight gain. Some researchers and manufacturers of cortisol-blocking diet supplements claim that excess cortisol stimulates glucose production. This excess glucose is then typically converted into fat and stored. How true are these claims, and if they are indeed sound, how can we keep stress from sabotaging our weight-loss efforts? 

Cortisol: The Stress Hormone
An important part of our daily hormone cycle, cortisol is a glucocorticoid produced by the adrenal gland and helps to restore homeostasis after stress, increasing production of glucose from protein to quickly increase the body’s energy supply. The hormone is an essential part of the body’s fight-or-flight response, but too much of it can be a bad thing. In our modern lives, when responses to stress more often involve sitting at our desks than they do running from a leopard, the excess energy cortisol makes available turns to fat. And when we’re exposed to chronic stress, we can experience a cortisol overload. 

Packing on the Pounds with a One-Two Punch
According to Shawn M. Talbott and William Kraemer, authors of The Cortisol Connection, cortisol contributes to weight gain on two fronts. When we first react to stress, our brains release a corticotropin-releasing hormone (CRH), which sends us into fight-or-flight mode. As our pupils dilate, our focus improves, and our breathing deepens, our appetites are also suppressed and our digestive systems shut off temporarily. At the same time, CRH triggers the release of cortisol and adrenaline, which help mobilize carbohydrates and fat for ready energy. Once the immediate stressor has passed, the adrenaline passes but the cortisol stays, to bring our bodies back into balance by increasing our appetites so we can replace the carbohydrates and fat we should have burned while combating the threat. 

Our bodies assume that we’ve just exerted ourselves physically and need to replenish our reserves by eating a lot of calories. But in the modern world, that’s just not so. Pamela Peeke, MD, author of Fight Fat After 40, observes, “In today’s modern world, this elegant survival mechanism may be an anachronism that causes the body to refuel when it doesn’t need to. Sustained stress keeps … cortisol, that cursed hunger promoter, elevated and … that keeps appetite up, too.” 

Insulin’s Role in Weight Gain
Chronic exposure to stress is also a problem, as it keeps insulin levels high, potentially leading to insulin resistance, a pre-diabetic condition. A constant state of excess cortisol production stimulates excess glucose, which is then converted into fat, says Robert M. Sapolsky, PhD, a professor of biological sciences and neuroscience at Stanford University. 

After a long period of elevated glucose levels, the brain and some of the body’s cells can fail to react to the presence of insulin in the bloodstream. This is called insulin resistance, or pre-diabetes, and often leads to Type 2 diabetes, a condition associated with obesity. 

Fat cells in the abdomen contain more cortisol receptors and are more sensitive to high insulin levels than fat cells in other areas of the body are, so stress and related high glucose often lead to weight gain around the midsection. A Yale University study compared women who stored fat primarily in their abdomens with women who stored it mostly in their hips, and found that the women with excess belly fat reported having more stressful lives and produced higher levels of cortisol than the women with fat on their hips did. The authors of the study concluded that cortisol causes fat to be stored in the center of the body. According to Talbott and Kraemer, this is the most dangerous place to carry extra pounds, as a big belly can lead to metabolic syndrome, diabetes, and heart disease. 

The Gender Gap
As with all aspects of weight loss, managing cortisol’s effects is a more difficult task for women than it is for men, according to a study by HCG Diet Direct, published in the Journal of Adolescent Health. The study assessed 111 boys and girls, ages eight to thirteen, for symptoms of depression and monitored their cortisol levels and body mass. Data collected during the study suggested that cortisol spikes are linked to depression in both sexes, but that the spikes lead to obesity only in girls. 

The study drew no conclusions about the connection between cortisol and obesity, but suggested it might be due to behavioral and psychological differences between boys and girls. For example, girls tend to eat to deal with anxiety and estrogen fluctuations more than boys do. And WebMD notes that adult women also tend to stress more than men do—probably about things like why it’s so much easier for our boyfriends to lose weight when we can’t fit into our jeans.

The CortiSlim Controversy
So if cortisol leads to weight gain, all we need is a diet pill that blocks the release of this hormone, and we’ll be able to scrub the chub, right? If only it were that easy! The truth is that we’re really not sure what cortisol’s relationship to weight gain is, and the Federal Trade Commission isn’t happy about marketing products based on sketchy science. In 2007, it charged the makers of CortiSlim and CortiStress, two “cortisol blockers” sold as weight-loss aids, with making false and unsubstantiated claims about their products’ effectiveness. The companies were forced to pay consumers millions of dollars in refunds and change their marketing strategies. 

The FTC acted on research into mutations of the proopiomelanocortin (POMC) gene, which may cause obesity but simultaneously decreases glucocorticoid levels, according to Tiffany Spudich, PharmD, writing for Project Aware, a Web site offering comprehensive health information for women. Research into the POMC gene shows that cortisol, while a factor, may not be the prime culprit in weight gain. Instead, glucocorticoids are more likely part of a larger chain of hormonal and neuronal signals that contribute to obesity. 

“There are multiple controls in our body that regulate body weight and appetite,” says Malcolm Low, MD, PhD, a senior scientist and associate director at the Oregon Health and Science University Center for the Study of Weight Regulation and Associated Disorders. “Glucocorticoids are clearly involved in control of body weight. But [they are] not the only hormone involved. There are multiple systems involved in the brain and outside the brain that regulate how much fat we are going to have and how much appetite. There is no simple answer to treating obesity.” 

Stress Reduction Is Its Own Goal
If there is no magic pill to lower cortisol and take off the pounds, how are we to combat the diet-destroying effects of our hectic lifestyles? The first step is to stop worrying about losing weight and regard stress reduction as an end in itself. Set aside a little bit of time every day—just half an hour will do—to try one or more of these relaxation techniques:

  • Exercise not only helps to reduce stress, but also helps to improve insulin sensitivity, according to Spudich. Just a brisk walk every day will burn calories and help distract you from whatever is causing stress in your life.
  • Meditation, yoga, and breathing techniques are important stress-reduction habits to incorporate into your daily life. They’ll help you control your physiological response to the fight-or-flight mechanism, but they do require practice.
  • Get enough sleep. It’s amazing what feeling well rested can do to change your outlook. 

Whatever You Call It, Stress Is Bad News
Regardless of whether cortisol is actually the number-one culprit in weight gain, studies show that there is some relationship between stress and belly bulge. And even if some of the science seems too sketchy to believe, it’s still a good idea to add some relaxation to our overburdened lifestyles. Stress less, and weight loss may follow.


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