Alternate-day fasting diet improves fructose-induced insulin resistance in mice

Increased fructose consumption is linked to insulin resistance, weight gain, hyperlipidemia and hypertension. Although the advantages of several dietary restriction regimens have been demonstrated, the effects of alternate-day fasting (ADF) on fructose-induced insulin resistance have not yet been studied. This study is based on a new modification on ADF by combining the fructose-rich solution (10% w/v) and regular mice diet. Mice were randomly allocated into four groups: ADF50% (50% restriction in chow food intake but ad libitum fructose drink), ADF100% (100% restriction for chow food but ad libitum fructose drink), control (ad libitum chow food intake plus tap water) and daily food and fructose (DFF) (had free access to both chow and fructose solution). Biweekly fasting blood sugar (FBS), glucose tolerance test (GTT) and insulin tolerance test (ITT) were conducted. All groups gained weight during the study (p<0.05). Body weights of DFF and control groups did not differ from that of ADF groups, but ADF50% gained more (p<0.01) weights than ADF100% through the study. Total calorie intake (feed+fast days) of ADF50% was higher than that of ADF100% (p<0.001) and control (p<0.03). In addition, ADF groups consumed more energy than the control and DFF groups in feed (ad libitum) days (p<0.05). At the end of the study, the mean FBS levels in the control and ADF100% groups were similar and significantly lower in relation to that of DFF and ADF50% groups (p<0.01). Measurements of area under the curve in GTT and ITT revealed that the ADF100% group was more insulin-sensitive than the DFF and ADF50% groups. In conclusion, these data suggest that the ADF100% improves fructose-induced insulin resistance in mice.