Intermittent fasting, made popular by the 5:2 diet, is no more effective at promoting weight loss than continuous dieting, a scientific review shows.

Routinely touted as the superior weight loss option, the 5:2 diet allows people to eat as usual for five days and then fast for two. For women, the “fasting” phase means eating 500 calories per day while men are allowed 600 calories.

The rationale behind this hugely popular eating pattern is that a period of non-fasting is followed by a short period of fasting or severe energy restriction and this has a metabolic advantage.

However, a review of 52 studies by researchers from the University of Sydney has found that while intermittent fasting results in weight loss – at least in the short term – it is no better than continuous energy restriction, i.e. being on a continuous diet.

The results suggest that intermittent fasting has no physiological benefits over continuous dieting for weight loss, say the researchers.

Instead, they found that both dieting strategies produced equivalent outcomes in terms of reduction of body weight, fat mass and fat-free mass. Furthermore, both diets showed similar dropout rates and improved stability of blood glucose levels.

Amanda Davey

Last Reviewed: 22/09/2015

Reproduced with kind permission from


Seimon RV, et al. Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Molecular and Cellular Endocrinology doi:10.1016/j.mce.2015.09.014.