Cortisol, a stress hormone, may be involved in your body's reaction to fight or flee, but that's not the hormone's only purpose. It also regulates whether your body uses carbs, protein or fat for energy. Chronically high cortisol levels may increase your risk of health issues, such as diabetes, obesity, suppressed immune system and heart disease. Cortisol plays a role in converting protein to glucose when your carb supply is low, which is why there is concern that a low-carb diets might play a role in elevating cortisol levels. However, there's currently no study linking a low-carbohydrate diet and increased cortisol.
Concerns With Cortisol
Your body releases cortisol when you first wake up in the morning, during exercise and when you're under stress. Cortisol triggers the release of glucose, to serve as a source of energy for the perceived stress and suppresses the release of insulin.
Unfortunately, the regular hustle and bustle of most people's lives may lead to a constant elevation of cortisol in the body, according to a 2009 article published in Today's Dietitian. If you're chronically stressed and cortisol is always elevated, it's theorized that it may increase your risk of diabetes. Excess weight gain is also a concern. Too much cortisol causes an increase in appetite and also an increase in abdominal fat accumulation. High cortisol is also linked to inflammation and heart disease, as well infertility and gastrointestinal upset.
Cortisol and a Low-Carb Diet
Carbs provide your body with energy in the form of glucose. When you're on a low-carb diet, your body is forced to use fat and protein to make glucose for energy, a process called gluconeogenesis. Cortisol plays a pivotal role in the activity of the steroid glucocorticoid, which is necessary for gluconeogensis. In theory, cortisol levels would be chronically elevated on a low-carb diet to help produce the energy from these noncarb sources.
However, low-carb diets may have the opposite affect, according to a 2007 study published in the Journal of Clinical Endocrinology and Metabolism. This study compared the effects of a low-carb, high-fat diet to a moderate-carb, moderate-fat diet on cortisol levels in the blood of healthy obese men. The researchers found that the low-carb, high-fat diet helped keep cortisol levels within normal range better than the moderate-carb, moderate-fat diet.
Low-Carb Diet vs. Cortisol on Health
While more research may be necessary to further validate the results of the 2007 study published in the Journal of Clinical Endocrinology and Metabolism, the low-carb diet seems to have more positive effects than negative, especially when it comes to the health consequences related to high cortisol levels. Restricting carbs isn't only a good way to drop unwanted pounds, but it's also good for shrinking your belly. And a low-carb diet improves blood sugar and triglyceride levels, lowering risk of diabetes and heart disease. As for inflammation, low-carb diets may help reduce factors that cause inflammation better than low-fat diets, according to 2014 study published in Annals of Medicine.
Anti-inflammatory Low-Carb Foods
While it's not certain how exactly a low-carb diet affects cortisol levels, including anti-inflammatory foods in your diet may help combat the effects of cortisol on your body. On a low-carb diet, that might mean eating more omega-3-rich salmon and tuna than meats high in saturated fat, such as New York strip and bacon. Antioxidant-rich veggies such as tomatoes, spinach, collards and kale are also good for helping your body manage stress and are low-carb to boot. Also, include healthier sources of fat, such as olive oil and avocados, which have more anti-inflammatory omega-3 and omega-6 fats. Adding more plant-based proteins, such as nuts and seeds, also ups your intake of these healthy fats.
- Today's Dietitian: Cortisol — Its Role in Stress, Inflammation, and Indications for Diet Therapy
- Annals of Internal Medicine: Advice to Follow a Low-Carbohydrate Diet Has a Favourable Impact on Low-Grade Inflammation in Type 2 Diabetes Compared With Advice to Follow a Low-Fat Diet
- Colorado State University: Glucocorticoids
- Journal of Clinical Endocrinology and Metabolism: Dietary Macronutrient Content Alters Cortisol Metabolism Independently of Body Weight Changes in Obese Men
- American Journal of Clinical Nutrition: Low-Carbohydrate Nutrition and Metabolism
- Harvard Health Publications: Foods That Fight Inflammation
- Academy of Nutrition and Dietetics: Inflammation and Diet