Intermittent fasting shows promise as therapy for diabetes, metabolic diseases

Intermittent fasting (IF) could not only lower body weight and convert unhealthy fats into energy-burning ones, it could be preventative for patients struggling with diabetes or metabolic disorders, a new study published in Cell Research reports.

Kyoung-Han Kim, PhD, and colleagues found that, in a 16-week, isocaloric trial in groups of mice, rodents who were fed for two days and then fasted for one lost more weight and saw greater health benefits than mice that were fed the same amount consistently. What the fasting achieved, Kim and co-authors wrote in their paper, was converting stores of white adipose tissue (WAT) into browner fat, which stimulates energy-burning processes in the cells.

Mice on a fasting regimen also saw more stable glucose and insulin systems, the authors noted—both of which are crucial in patients who live with diabetes mellitus or obesity.

WAT is commonly associated with development of obesity and type 2 diabetes for a reason, but it’s also an important component of energy homeostasis, Kim et al. explained. Fat stores excess energy produced by the body and releases lipids in response to critical energy deficits. When WAT is “browned,” it also regulates thermogenic activity, which aids whole-body metabolism.

Browned fat, which is known to improve insulin sensitivity, takes energy to create. Physiological stimuli like exposure to cold and exercise trigger the browning of WAT, which increases a body’s energy expenditure, burning off excess calories. For this reason, WAT browning has been suggested as a possible approach to combatting the world’s ever-growing obesity epidemic.

“Modern lifestyles favor longer periods of daily energy intake and shorter fasting periods,” Kim and colleagues wrote. “This erratic eating pattern is associated with metabolic disadvantages and contributes to the current global obesity and diabetes epidemic. Fasting brings various positive health impacts, suggesting that modulation of fasting period can be used as a therapeutic intervention.”

The health benefits of intermittent fasting have been proven in the past, the authors noted, providing health benefits equal to prolonged fasting or calorie restriction. But, while IF has been suggested to combat cardiovascular disease, neurodegenerative disease, cancer and aging, clinicians haven’t been sure whether those metabolic benefits are stemming from IF itself or reduced food intake—a problem common in rodent models that results in underfeeding.

“While WAT is one of the most critical organs for fasting physiology, it is not known whether the molecular alteration of WAT after IF is a driver or an outcome of IF-mediated benefits,” Kim and co-authors wrote.

The researchers established a new IF regimen in the mice they studied and, after analyzing four-month results, found IF tempered an immune reaction in fat cells that triggered anti-inflammatory macrophages. These white blood cells send a message to fat cells to burn stored fats or lipids, subsequently generating heat. The process seemed to be a result of an increase in vascular endothelial growth factor (VEGF), which stimulates white blood cells, during IF.

In a six-week trial, Kim and colleagues saw similar results in the mice.

“Our data demonstrate that metabolic benefits of IF are largely mediated by adipose thermogenesis without overall caloric reduction,” the authors wrote. “The present study illustrated the role of IF-induced adipose-VEGF in remodeling the immunometabolic property of adipose tissue, highlighting the importance of eating pattern and physiological fasting duration to sustain metabolic homeostasis.”