Effects of intermittent fasting on glucose and lipid metabolism

Abstract

Two intermittent fasting variants, intermittent energy restriction (IER) and time-restricted feeding (TRF), have received considerable interest as strategies for weight-management and/or improving metabolic health. With these strategies, the pattern of energy restriction and/or timing of food intake are altered so that individuals undergo frequently repeated periods of fasting. This review provides a commentary on the rodent and human literature, specifically focusing on the effects of IER and TRF on glucose and lipid metabolism. For IER, there is a growing evidence demonstrating its benefits on glucose and lipid homeostasis in the short-to-medium term; however, more long-term safety studies are required. Whilst the metabolic benefits of TRF appear quite profound in rodents, findings from the few human studies have been mixed. There is some suggestion that the metabolic changes elicited by these approaches can occur in the absence of energy restriction, and in the context of IER, may be distinct from those observed following similar weight-loss achieved via modest continuous energy restriction. Mechanistically, the frequently repeated prolonged fasting intervals may favour preferential reduction of ectopic fat, beneficially modulate aspects of adipose tissue physiology/morphology, and may also impinge on circadian clock regulation. However, mechanistic evidence is largely limited to findings from rodent studies, thus necessitating focused human studies, which also incorporate more dynamic assessments of glucose and lipid metabolism. Ultimately, much remains to be learned about intermittent fasting (in its various forms); however, the findings to date serve to highlight promising avenues for future research.

Wilson disease: At the crossroads between genetics and epigenetics—A review of the evidence

“…174 Common fasting practices include the 5:2 plan (feed for 5 days and restrict calories to <70% for 2 days each week), alternate day fasting, and restricting eating to a 12-hour window each day. 175 However, few studies have examined the metabolic effects of fasting in humans; therefore, no recommendations regarding WD and fasting can be made with confidence at this time.…”

Intermittent fasting in Type 2 diabetes mellitus and the risk of hypoglycaemia: a randomized controlled trial

“…The degree of caloric restriction may vary from partial to complete restriction. The schedule may involve restriction for several hours a day, alternate days or several days per week . A systematic review, but without meta‐analysis, of studies comparing intermittent fasting with daily energy restriction reported the same degree of weight loss between the two treatment options in nine out of 12 studies (75%).…”

Efficacy of an intermittent energy restriction diet in a primary care setting

“…In recent years, the interest surrounding intermittent energy restriction (IER) as a potential strategy to improve compliance to energy-restricted diets has increased [3] although findings from a recent systematic review comparing IER to CER demonstrate equivalence [4]. Nonetheless, studies conducted demonstrate that IER is an effective strategy for weight loss and improving cardiometabolic health markers such as fasting insulin, lipids and blood pressure when delivered in controlled settings [5], whilst weight maintenance rates have been shown to be comparable to CER [6].…”