Introduction: Intermittent fasting (IF) is an alternative dietary pattern that imposes the complete or partial restriction of all sources of calories for a specific period in time. In-between these periods there is a restricted time window to consume calories in the form of food, drinks, etc. IF is one of the most popular regimens amongst dieters worldwide. Despite the popularity of this dietary pattern, there are plenty of misconceptions regarding both the benefits and health risks of IF.
Review Results: Intermittent fasting does not appear to produce any metabolic advantages or disadvantages compared to other methods for calorie restriction despite the effects on hormones, meal skipping, and the effect of continuous fasting on energy expenditure. It is as effective as continuous energy restriction in improving body weight and cardiovascular risk factors. IF might also provide benefits against oxidative stress and inflammation. Its effect on autophagy is not yet investigated in humans. Despite the benefits for weight loss and metabolic health, certain population groups such as women with normal and low body weight might experience worsened glucose tolerance due to fasting. There is also a risk for hypotonia, hypoglycemia, menstrual problems, and others.
Conclusion: IF is as effective as continuous calorie restriction and there do not appear to be any metabolic advantages or disadvantages related to fasting. Long-term adherence might be an issue for a significant percentage of dieters. Currently, there is a lack of evidence for the long-term safety and effectiveness of IF regimens.
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