Fasting shown to improve cardiometabolic health.
Total caloric desistance (TDC) is a medical term for completely abstaining from calories for a certain period of time; it’s more commonly known as fasting. TDC may be done through intermittent fasting, alternate day fasting, routine periodic fasting, or intermittent energy restriction.
Total caloric desistance has produced a variety of beneficial health effects in animal models, although high-quality research in humans has been limited.
Most research has examined the 5:2 fasting plan, which restricts calorie intake two days a week while allowing normal eating the other five. There’s also promising research on diets that impose fasting every other day, referred to as alternate-day fasting plans, and on time-restricted fasting, which are diets that restrict daily food consumption to a six or eight-hour window.
Research done by Benjamin Horne, director of cardiovascular and genetic epidemiology at Utah’s non-profit Intermountain Healthcare system has shown that intermittent fasting has weight loss benefits, can reduce body fat and inflammation, can improve insulin resistance, and has beneficial effects on the cardiovascular system by reducing blood pressure and resting heart rate and reduction in blood lipids. Fasting has shown to shift the body’s cellular and metabolic processes in ways that promote optimal health. Horne and his colleagues conducted a systemic review that looked at three randomized controlled clinical trials that evaluated the effects of fasting on surrogate outcomes (such as weight and cholesterol) and two observational studies that looked at clinical outcomes (such as diabetes and coronary artery disease). From the observational studies, patients who reported routine fasting had a lower odds of coronary artery disease and diabetes. The randomized controlled trials found that patients in the fasting group compared to the control group had improvements in weight and in other cardiovascular and metabolic pathways such as triglycerides, LDL cholesterol, C-reactive protein. No safety outcomes where studied.
They concluded that while these studies support the existence of a health benefit from fasting, these findings are useful in developing substantial further research in humans before the use of fasting as a health intervention can be recommended.
Mark Mattson (Interview with Mark Mattson) chief of the Laboratory of Neurosciences at the National Institute on Aging and a professor of neuroscience at the Johns Hopkins School of Medicine, has published multiple studies and reviews on intermittent fasting. He describes that through intermittent fasting, people undergo a metabolic switch in which the liver’s energy stores are depleted, and so the body’s cells start using fat and ketones for energy. This switch is a form of mild challenge to the human body that he compares to exercise, just as running or lifting weights stresses the body in beneficial ways, the stress imposed by fasting appears to induce some similarly beneficial adaptations. These cycles of challenge, recovery, challenge, and recovery seem to optimize both function and durability of most cell sites.
A recent article by the Texas State University talks about the benefits of intermittent fasting, including cardio metabolic health, improvements in body composition, reduction in inflammation and improvements in blood lipids. They studied two groups that consisted of 22 healthy active men. One group ate the same number of calories that they normally eat and the other group was allowed to eat as many calories as they would like. Both groups benefited equally from the diet. One group fasted for eight hours of the day. The evidence showed reduced blood pressure, reduced body weight and improved blood cholesterol. The university plans to broaden their study to include people with greater health risks. The study is yet to be released.
The results of these studies are useful as a primary source to help in developing longer-term trials as well as assessing if there are any long-term risks associated with intermittent fasting.
Interview with Mark Mattson: http://www.diabetesincontrol.com/what-is-intermittent-fasting/
- With the limited amount of evidence available regarding total caloric desistance, it has shown great promise in promoting health, including cardiovascular benefits and improvement in insulin resistance.
- There is more than one approach to total caloric desistance, all of which have shown benefits.
- Long-term risks associated with total caloric desistance are still unknown.
Horne BD, Muhlestein JB, Anderson JL. Health effects of intermittent fasting: hormesis or harm? A systematic review. Am J Clin Nutr. 2015 Aug;102(2):464-70.
Dahlia Elimairi, Pharm D student at UC Denver Skaggs School of Pharmacy