The Ultimate Breakdown: Fasting vs Caloric Restriction
Updated: Feb 18, 2020
So, you would have heard hundreds and thousands of coaches, personal trainers and even nutritionists talk about how caloric restriction is all you need to do to burn fat and stimulate weight loss. They say how the benefits of intermittent fasting is just from the beneficial effects of calorie deficits. These people are what we call IDIOTS. Yes, a lot of the same benefits are seen from caloric restriction as they are seen from fasting protocols but guess what, not everything is about fat loss, because prior to fat loss, health should be your number one priority. But not just that, fasting can accelerate the effects of a calorie restrictive nutrition protocol.
I have been reading through numerous pieces of literature showing the findings of recent studies on this debate. And, the findings are just as I expected. Fasting protocols have outstanding health benefits that are far superior to the simple benefits of caloric restriction. Here are some of my findings:
Ina study (2019) comparing intermittent calorie restriction and continuous calorie restriction in men with obesity, greater weight loss was seen in the ICR group (12.6% vs 7.2%). Fat mass loss was also greater in the ICR group nearing double the fat loss effects of just caloric restriction alone.
Further studies comparing intermittent fasting against calorie deficits show that weight loss is very similar but still is marginally better through the alternate day fasting protocol. ADF saw a reduction of 8.8% total weight and the calorie deficit group saw just a 6.2% drop. Again this shows the superiority of fasting protocols against calorie restriction, even if this study was only a marginal difference.
I then went on to read about the glucose metabolism and insulin sensitivity effects of fasting protocols and low and behold, more good news for fasting procedures. In the study, the groups that sustained an alternate day fasting protocol maintained a stable weight, however, insulin sensitivity improved, indicated through significant increases is glucose infusion rate, adoponectin and inhibition of insulin-mediated lipolysis. Disclaimer for this study: the same results were not seen in a further study using only a 14 hour fasting window, so the beneficial effects of the fasting protocol were >14 hours.
Again, results are backed up in a further study - in a randomised control trial, 3 different groups were tested for effects on insulin sensitivity and fat mass loss. Group 1 were just continuous energy restriction (CD), group 2 were carbohydrate and energy restricted intermitted fasting with ad-lib protein and fat intake, and group 3 were just the same but without the ad-lib protein and fat intake. The last two groups (fasting) both experienced greater improvements in insulin sensitivity than the calorie deficit group, at the same time both the fasting groups saw a larger reduction in body fat although total weight loss was not significantly different - meaning the retention of muscle tissue was far greater also.
And that is all from just a body composition side of things. My further reading went on to look at the effects fasting has on the cardiovascular system (great) and the gut microbiome (really great) and the effects fasting has on brain health, cognition and concentration (good again) and the hormetic effects of fasting. But I can bore you with that some other time.
So to all of you out there that believe caloric restriction is the only way forward, and that fasting has no further benefits other than the effects of a calorie deficit, please broaden your horizons, and stop hiding behind caloric deficits *cough*James Smith*cough*
Luke French, Health Coach