Modified alternate-day fasting and cardioprotection: relation to adipose tissue dynamics and dietary fat intake

The relation between alternate-day fasting (ADF) and cardioprotection remains uncertain. In the present study, we examined the ability of modified ADF, with a low-fat (LF) vs high-fat (HF) background diet, to modulate adipose tissue physiology in a way that may protect against coronary heart disease. In a 4-week study, male C57BL/6 mice were randomized to 1 of 3 groups: (1) ADF-85%-LF (85% energy restriction on fast day, ad libitum fed on feed day, on an LF diet), (2) ADF-85%-HF (same protocol but HF diet), and (3) control (ad libitum fed). Throughout the study, body weight did not differ between ADF and control animals. Proportion of subcutaneous fat increased (P<.01), whereas the proportion of visceral fat decreased (P<.01), in both ADF groups. Triglyceride (TG) synthesis was augmented (P<.05) in subcutaneous fat, but remained unchanged in visceral fat. Adiponectin concentrations were elevated (P<.05), whereas leptin and resistin levels decreased (P<.05). Aortic vascular smooth muscle cell proliferation was reduced (P<.05) by 60% and 76% on the LF and HF diets, respectively. Plasma total cholesterol, TG, and free fatty acid concentrations also decreased (P<.05). In summary, modified ADF regimens alter adipose tissue physiology (ie, body fat distribution, TG metabolism, and adipokines) in a way that may protect against coronary heart disease. These beneficial effects were noted over a wide range of fat intake, suggesting that ADF may be protective even in the presence of HF diets. (C) 2009 Elsevier Inc. All rights reserved.