Most people admit that when they're under stress, healthy eating habits can be difficult to maintain. Whether eating to fill an emotional need or grabbing fast food simply because there's no time to prepare something healthy, a stressed-out lifestyle is rarely a healthy one. But weight gain when under stress may also be at least partly due to the body's system of hormonal checks and balances, which can actually promote weight gain when you're stressed out, according to some researchers.
Cortisol, the stress hormone
Cortisol is a critical hormone with many actions in the body. Normally, cortisol is secreted by the adrenal glands in a pattern called a diurnal variation, meaning that levels of cortisol in the bloodstream vary depending upon the time of day (normally, cortisol levels are highest in the early morning and lowest around midnight). Cortisol is important for the maintenance of blood pressure as well as the provision of energy for the body. Cortisol stimulates fat and carbohydrate metabolism for fast energy, and stimulates insulin release and maintenance of blood sugar levels. The end result of these actions can be an increase in appetite and can cause cravings for sweet, high-fat, and salty foods. With elevated cortisol levels, the body also produces less testosterone, leading to a decrease in muscle mass. With less testosterone to build muscle mass, your body starts to burn fewer calories.
Cortisol has been termed the "stress hormone" because excess cortisol is secreted during times of physical or psychological stress, and the normal pattern of cortisol secretion (with levels highest in the early morning and lowest at night) can be altered. This disruption of cortisol secretion may not only promote weight gain, but it can also affect where you put on the weight in the body. Some studies have shown that stress and elevated cortisol tend to cause fat deposition in the abdominal area rather than in the hips. This fat deposition has been referred to as "toxic fat" since abdominal fat deposition is strongly correlated with the development of cardiovascular disease, including heart attacks and strokes.
What causes abnormal cortisol levels?
Stress is certainly not the only reason having for abnormal levels of cortisol. A number of diseases and conditions can result in abnormal levels of cortisol in the bloodstream. Cushing's syndrome is a term used by doctors to describe a condition in which various medical problems result in very high levels of cortisol, leading to changes in the body's appearance and function.
Weight gain or loss is dependent on a number of factors including resting metabolic rate, food intake, amount of exercise, and even the types of food consumed and the times of day food is consumed. Genetic factors also likely influence our metabolism and may explain some people's tendency to gain or lose weight more rapidly than others.
Whether or not a particular individual's stress levels will result in high cortisol levels and weight gain is not readily predictable. The amount of cortisol secreted in response to stress can vary among individuals, with some people being innately more "reactive" to stressful events. Studies of women who tended to react to stress with high levels of cortisol secretion have shown that these women also tended to eat more when under stress than women who secreted less cortisol. Another study demonstrated that women who stored their excess fat in the abdominal area had higher cortisol levels and reported more lifestyle stress than women who stored fat primarily in the hips.
How to lower stress levels
The diet industry has attempted to capitalize on findings from these studies by promoting dietary supplements claiming to lower cortisol and enhance weight loss. No independent studies published in respected, peer-reviewed medical journals have shown that these supplements have any value in cortisol reduction or weight loss. In fact, exercise is the best method for lowering cortisol levels that have risen in response to stress and has the added benefit of burning calories to stimulate weight loss. Practices such as meditation, yoga, and other relaxation techniques can also be used to keep cortisol levels in check.
Abraham, et al. "Cortisol, obesity and the metabolic syndrome: A cross-sectional study of obese subjects and review of the literature." Obesity 2013.
Epel, E.S., et al. "Stress and body shape: stress-induced cortisol secretion is consistently greater among women with central fat." Psychosom Med 62.5 Sep-Oct 2000: 623-32.
Peeke, P.M., and G.P. Chrousos. "Hypercortisolism and Obesity." Ann NY Acad Sci 771 Dec 29, 1995: 665-76.