Could Intermittent Energy Restriction and Intermittent Fasting Reduce Rates of Cancer in Obese, Overweight, and Normal-Weight Subjects? A Summary of Evidence

Abstract

Animal studies and human observational data link energy restriction (ER) to reduced rates of carcinogenesis. Most of these studies have involved continuous energy restriction (CER), but there is increasing public and scientific interest in the potential health and anticancer effects of intermittent energy restriction (IER) or intermittent fasting (IF), which comprise periods of marked ER or total fasting interspersed with periods of normal eating. This review summarizes animal studies that assessed tumor rates with IER and IF compared with CER or ad libitum feed consumption. The relevance of these animal data to human cancer is also considered by summarizing available human studies of the effects of IER or IF compared with CER on cancer biomarkers in obese, overweight, and normal-weight subjects. IER regimens that include periods of ER alternating with ad libitum feed consumption for 1, 2, or 3 wk have been reported to be superior to CER in reducing tumor rates in most spontaneous mice tumor models. Limited human data from short-term studies (≤6 mo) in overweight and obese subjects have shown that IER can lead to greater improvements in insulin sensitivity (homeostasis model assessment) than can CER, with comparable reductions in adipokines and inflammatory markers and minor changes in the insulin-like growth factor axis. There are currently no data comparing IER or IF with CER in normal-weight subjects. The benefits of IER in these short-term trials are of interest, but not sufficient evidence to recommend the use of IER above CER. Longer-term human studies of adherence to and efficacy and safety of IER are required in obese and overweight subjects, as well as normal-weight subjects.

Intermittent calorie restriction largely counteracts the adverse health effects of a moderate‐fat diet in aging C57BL/6J mice

“…During the last decade the health‐promoting and life‐extending effects of a wide variety of variants of a standard CR diet have been examined in both humans and models species 29, 57, 58, 59, 60, 61, 62. The major differences between the dietary variants of intermittent calorie restriction are (1) the extent of calorie reduction varying from complete fasting to a mild decrease in calorie intake and (2) the time window when the fasting/CR is applied in combination with the period in between the fasting/CR cycles.…”

Dietary restriction of amino acids for Cancer therapy

“…Besides the intermittent dietary restriction of lysine with normal maize, intermittent globe AA restriction is also practically feasible and beneficial by welldocumented intermittent fasting [87][88][89][90], or using those common foods in Fig. 4b except cereals and grain products with great cautiousness for protein malnutrition.…”

Metabolic Effects of Intermittent Fasting

“…Reviews and meta-analyses have compared the efficacy of fasting regimens with continuous energy restriction (6,44,48,91,107). The authors of these publications unanimously report that, given the current state of the evidence, the overall metabolic benefits of fasting regimens are not superior to those of continuous energy restriction.…”