Intermittent fasting is difficult to define precisely but it is best described as time restricted eating. The idea is that such a diet mimics how humans ate historically compared to today where people eat whatever and whenever they want. There has been several animal studies and limited human studies that show this approach is effective for weight loss, blood pressure reduction and glucose control. However, a recent well-designed study suggested differently.
This Chinese study was for 12 months. It involved overweight to obese individuals and the men were placed on a 1,500-1,800 calories per day and the women on 1,200-1,500 calories per day. The study finished with 119 participants and divided them into a time restricted group (8 hours of eating) that lost seventeen pounds and a non-restricted group who loss was fourteen pounds.
More telling is that there were no differences between the two groups in terms of blood pressure, percent of body fat, blood glucose, and lipids (fats). All these measures improved equally in both groups. The study authors conclusion was that intermittent fasting does not work compared to other dieting approaches. Also noteworthy, the negative effects of fatigue, dizziness and headaches were the same in both groups.
I draw a different conclusion. First the difference between a loss of fourteen pounds to seventeen pounds is over 20% and that is significant. Second, the difference in the two groups in triglycerides was -30%, blood glucose -16% and HDL +50% all markers of metabolic health were better in the fasting group. Third anytime you restrict your calorie intake so dramatically this is an enormously powerful positive effect on your health. Fourth, Culturally, Chinese people eat their biggest meal midday compared to Americans who eat their biggest meal in the evening which is worse for metabolic health. Finally, I have been doing my own version of an intermittent fasting for a decade and I find it easier to maintain then if I had to count calories and diet. I suspect that might be true for others.
If you are interested in my version/experience in time restricted eating, please ask me on your next visit.