Intermittent fasting no better than continuous energy restriction for weight loss
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If you’ve been considering the 5:2 diet the findings of this recently published study may be of interest.
Supporters of intermittent fasting (such as the popular 5:2 diet) suggest that it offers greater benefits for weight loss over continuous energy restriction. But a group of Australian researchers have reviewed the findings from 40 studies looking at intermittent fasting and found that the evidence doesn’t support this claim.
When we restrict our energy intake our body adapts to this restriction which can slow down and prevent further weight loss – this is why we often hit a weight plateau. It has therefore been suggested that an intermittent return to energy balance (ie increasing our food intake again) may help by encouraging our body to start burning energy again. This is the idea behind intermittent fasting.
However when the authors of this paper looked at the results of 40 studies on intermittent energy restriction, they found that while it did reduce body weight, BMI and fat mass, as well as improving blood glucose and insulin levels, similar benefits were found with continuous energy restriction.
Interestingly, they found that despite the expectation that ‘fasting’ might lead to compensatory overeating on ‘feast’ days, intermittent fasting tended to lead to reduced food intake even on non-fasting days. One explanation for this is that intermittent fasting may reduce appetite, although the authors note that there were insufficient studies available to draw a conclusion on this point.
The conclusion? Intermittent fasting is one option for losing weight but is no better than continuous energy restriction, so it really comes down to individual preference.
Seimon et al. Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Molecular and Cellular Endocrinology (2015), doi: 10.1016/j.mce.2015.09.014.