There has been a lot of hype in recent years about intermittent fasting.
One of the most well-publicised intermittent fast diet is the 5:2 diet, which involves eating normally and sensibly for five days a week and then cutting caloric intake on the other two days to 500 calories for women and 600 calories for men. There are countless other variations of intermittent fasting, like 24 hour fasts where only water is permitted and alternate day fasting and feasting. Intermittent fasting has been promoted as beneficial to a variety of health outcomes, one of the main ones being weight loss. There’s mixed research about the benefits of intermittent fasting for weight loss, particularly when it comes to weight loss maintenance over the long term. Researchers reviewed the available evidence to investigate the association between intermittent fasting and weight and metabolic outcomes.
The studies that were included for analysis involved some form of intermittent fasting that was adhered to for more than six months. The studies compared this form of dieting with traditional calorie-restricted diets. They found that the difference in weight loss between the two approaches to dieting was negligible. Furthermore, rates of adherence to the diet interventions were similar. Changes in levels of blood lipids, glucose and insulin were not significantly different between the intermittent fasting approach and a continuous energy restriction approach.
This research suggests that while intermittent fasting might be positive for weight loss efforts, it may be no more superior to a more traditional and less extreme calorie-restricted diet. This might be particularly relevant when considering weight loss maintenance over time. The take home message is that there is no miracle diet that’s foolproof and suits everyone. The safest bet is to talk to your doctor who can help you choose an evidence-based diet that is well suited to your lifestyle and therefore that you are more likely to maintain over the long term.
Reference: Headland, M et al. Weight-loss outcomes: a systematic review and meta-analysis of intermittent energy restriction trials lasting a minimum of 6 months. Nutrients 2016.