Billions of dollars are spent annually to combat the trend toward obesity and its detrimental health consequences. Fast food, lack of exercise, and even fad diets have topped the list of usual suspects leading to an overweight Canadian population. However, despite the best efforts to lose weight, many of us still struggle. So what could be causing this?
Some researchers hypothesize that another component may play an important role in the battle of the bulge: a critical hormone working in our bodies daily, called cortisol.
What is cortisol?
Cortisol, a stress hormone, is the primary actor during the stress response. This hormone primes the body by activating the fight-or-flight response, a vital survival mechanism designed to prepare us to deal with a stressor by either fighting it or escaping it.
Cortisol stimulates the release of glucose into the blood, along with amino acids and fatty acids for energy, in order to effectively mobilize the body for action. It is secreted by the adrenal glands daily, with levels highest in the early morning and gradually declining into the night.
What, exactly, is stress?
Hans Selye, a Hungarian endocrinologist who pioneered the study of the effects of stress on the human body, defined stress as “the nonspecific response of the body to any demand made upon it.” Although not all stress is bad, a negative perceived stress can be described as a state of threatened homeostasis, or disharmony.
The stress response is critical to survival, as it helps us adapt to challenges and maintain equilibrium. However, it is meant to be short-lived so that once the perceived threat has passed, the body then self-regulates, and cortisol levels typically return to normal. Stress that is constant or chronic, however, leads to unhealthy states, such as compromised immune function, developmental impairment, and weight gain.
What is the cortisol/weight connection?
Elements of modern living, Western diets, environmental stressors, and sleep deprivation leave many of us feeling stressed out on a regular basis. Adding lack of physical activity to this regular stress means that excess cortisol is produced, which remains in our blood for longer periods, eventually disrupting various metabolic functions.
This in turn can cause glucose intolerance, hypertension, loss of muscle mass, and high insulin levels. Several studies have shown that these disturbances are linked to weight gain, particularly abdominal fat or central obesity. Consequently, the development of a cluster of metabolic disorders, such as type 2 diabetes, metabolic syndrome, cardiovascular disease, and cerebrovascular disease, have been associated with obesity.
How does this work?
Persistent, long-standing stress gives rise to chronic, elevated cortisol levels, causing cellular and tissue alterations. Fat cells (adipocytes), in particular, contain a specific enzyme (11ß-HSD1) that converts cortisol into its active form, and studies show that human visceral fat cells (fat surrounding organs deeper in the abdominal cavity) contain more of this enzyme than subcutaneous fat cells (fat under the skin).
Thus, higher levels of these enzymes are found in the deep fat cells, resulting in more production of cortisol and greater blood flow, which may contribute to the enlargement of fat cells and further accumulation of fat. Research also points to impaired blood sugar control and insulin resistance in these cells where the enzyme activity is highest, indicating the development of diabetes.
Let’s face it, stress is an unavoidable part of life, and enduring a high level of stress is almost a badge of honour in today’s fast-paced digital age. When the body encounters stress, it coordinates a series of adaptive responses to deal with it and protect against chronic disease.
So it’s not the classic fight-or-flight response that is the problem; rather it is chronic hyperactivation of these systems and the inability to cope with long-term adverse stressful events throughout the lifespan.
The good news is that certain lifestyle factors can considerably minimize stress to reduce circulating cortisol levels, thereby achieving a slimmer waistline. A healthy diet and plenty of exercise are among the best contenders in this regard, both of which also improve insulin sensitivity and decrease inflammation. (See below for more suggestions.)
The triggers underlying the stress response reveal an elegant balance of stimuli and responses within a complex system. Chronic stress initiates subtle changes, which eventually disrupt this balance and result in detrimental health consequences.
Elevated cortisol impacts many functions and interacts with various hormones that may contribute to the obesity epidemic. Keeping cortisol levels at bay with lifestyle changes yields many wonderful health benefits. Eliminating stress is not an option, so dealing with it effectively is the key.
The other hormonal players in body weight
Body weight is also regulated by other hormones within a complex system allowing for energy balance. Two key players are leptin and ghrelin, both of which regulate food intake by controlling satiety or appetite stimulation, respectively.
Leptin suppresses appetite and follows a circadian rhythm with lower levels during the day, rising at night. Sleep deprivation, therefore, reduces leptin levels, stimulating food intake. In the presence of elevated cortisol, leptin levels also increase, leading to impaired signals for satiety and, therefore, increased eating.
Ghrelin acts to stimulate appetite and has been shown to increase during the stress response mediated by the effects of cortisol. Ghrelin’s actions also include its reward-enhancing and antidepressant properties, which in the human experience typically draw us toward more calorie-dense foods or “comfort foods.”
Studies also show that both of these hormones are intricately involved with the brain-reward system, indicating a preference for foods containing carbohydrates and sweet and salty snacks. It has been suggested that consuming palatable foods appears to dampen some of the physiological effects of stress.
What can you do?
Stimulants such as coffee, alcohol, or cola, which are also dehydrating, may heighten the negative effects of stress, resulting in elevated cortisol.
Eat lean protein
A balanced intake of lean meat, poultry, and fish, as well as grains and nuts, is necessary for the vitamins, minerals, and essential fatty acids they provide.
Eat plenty of vegetables
Brightly coloured fruits and vegetables containing phytonutrients, such as berries, citrus fruits, green leafy vegetables, and tomatoes, are encouraged for their antioxidant and anti-inflammatory properties.
Add flavonoid-rich foods
Foods rich in flavonoids, such as apples, onions, and grapefruit, can counteract the activity of the enzyme that converts cortisol into its active form, thus blunting excess cortisol production in visceral fat cells.
Get enough exercise
Exercise leads to the production of dopamine and serotonin, the feel-good chemicals produced in the brain responsible for the well-known effect of “runner’s high,” which helps control the stress response.
Supplement with herbs
Botanicals such as magnolia or holy basil are also useful in managing stress effectively.
- Magnolia bark is well known for its anxiety-reducing effects without causing sedation. Recent research with individuals who identified themselves as typically eating more in response to stressful situations and who reported high cortisol levels, increased weight gain, and sleep disturbances were found to show changes in cortisol levels along with feelings of well-being and reduced anxiety after taking a blend of bark extracts from magnolia and Amur cork trees.
- Holy basil exerts similar effects through its adaptogenic and antioxidant action, and also stimulates serotonin.
Get plenty of sleep
Good quality sleep is an equally important regulator of cortisol metabolism and plays a crucial role in energy balance. Sleep deprivation is a chronic stressor that may affect the resiliency of the body’s stress-response systems. Furthermore, poor sleep impacts leptin levels. A recent study showed disrupted leptin levels associated with sleep restriction, resulting in an increase in food intake.
Stress reduction strategies undoubtedly include practices such as mindful meditation, yoga, and other relaxation exercises to counteract rising cortisol levels as well as to improve sleep duration, mood disturbances, and fatigue.