Fasting fiction: is intermittent fasting superior to conventional dieting?

Objective: The obesity epidemic presents a major challenge to health and chronic disease, most notably cardiovascular disease. With the global burden of obesity expected to continue to increase, many strategies for weight loss have been developed. Intermittent fasting (IF) is a weight loss technique characterised by short periods of semi-restricted food intake interspersed with extended periods of fasting. This is in contrast to continuous restriction (CR) diet regimens, which reduce the total number of calories consumed in a conventional eating schedule. There is some evidence, particularly in animal studies, that IF is more effective for weight loss compared to CR. This systematic review aims to compile and evaluate all the human trials of IF and CR to determine whether there is a clear advantage of one technique over the other. Methods: A search using relevant keywords yielded 659 articles, of which seven were found to meet the inclusion criteria for this analysis. These seven articles investigated a variety of different fasting regimens. Results: None of the studies demonstrated a significant difference in weight loss between the IF and CR groups. There is some evidence to suggest that IF might be more effective than CR because it is more conducive to diet adherence. Conclusions: Within the current literature, there is no definitive answer as to whether IF is superior to CR for weight loss. Additional human studies should be conducted to better clarify this clinically relevant question, and should include adherence as part of their analysis.