While weight loss is an evidence-supported benefit of intermittent fasting, it’s not the only one. New research shows that regularly engaging in intermittent fasting (or Cleanse Days) can significantly improve cognition and possibly support brain health as we age—all the more reason why Cleanse Days should be thought of as lifelong habits rather than used as a short-term solution.
The recent study was conducted by researchers at Kaiser Permanente Colorado and reported at Obesity Week—a prestigious conference held annually. In the randomized, pilot study, 26 obese subjects were divided into two groups: an intermittent fasting group that fasted every other day with no calorie restrictions on “feeding” days and a group that followed a standard weight loss diet.
After two months, subjects in the fasting group lost the same amount of body weight than those who followed a standard diet without fasting (an average of 6.5 percent body weight compared to 5.75 percent, respectively). However, four months after the intermittent portion of the study was complete, researchers checked back in with the subjects and found that those who had engaged in intermittent fasting lost more weight, especially visceral fat, and had greater improvements in cognitive function than those who did not fast.
William Troy Donahoo, Ph.D., the lead researcher of the study, believes that one of two things could have caused this result. First, the people in the study could have continued some form of fasting after the study had ended. Second, fasting could have caused an improved metabolic state that offered delayed benefits. Per an article in Medpage Today, Donahoo theorizes that fasting could have altered the metabolism of subjects so they were, “more flexible shifting between carbs and fat for fuel, or less leptin resistant.”
In addition to continued weight loss, researchers found that subjects who fasted had significant cognitive improvements, specifically improvements in memory, compared to the other group. Also, fasting subjects showed trends of increased brain-derived neurotropic factor (BDNF), a marker of cognitive function.
Links between brain health and intermittent fasting have been studied for over a decade. Mark Mattson, Ph.D., of the National Institute on Aging has published many articles outlining cognitive improvements in mice; however, this is the first study showing similar outcomes in humans.
Donahoo went on to conclude that this research provides, “preliminary evidence of enduring visceral fat-reducing and cognition-enhancing alternate-day intermittent fasting in humans.”
Gozansky et al. Intermittent fasting reduces abdominal obesity and improves cognitive function in obese adults. Obesity Week, 2013; Abstract P-537.