Intermittent fasting may impart metabolic benefits independent of energy balance by initiating fasting-mediated mechanisms. This randomized controlled trial examined 24-h fasting with 150% energy intake on alternate days for 3 weeks (0:150; n=12). Control groups involved a matched degree of energy restriction applied continuously without fasting (75% energy intake daily; 75:75; n=12) or a matched pattern of fasting without net energy restriction (200% energy intake on alternate days; 0:200; n=12). Primary outcomes were body composition, components of energy balance, and post-prandial metabolism. Daily energy restriction (75:75) reduced body mass (-1.91+/-0.99 kg) almost entirely due to fat loss (-1.75+/-0.79 kg). Restricting energy intake via fasting (0:150) also decreased body mass (-1.60+/-1.06 kg; p=0.46 versus 75:75) but with attenuated reductions in body fat (-0.74+/-1.32 kg; p=0.01 versus 75:75), whereas fasting without energy restriction (0:200) did not significantly reduce either body mass (-0.52+/-1.09 kg; p≤0.04 versus 75:75 & 0:150) or fat mass (-0.12+/-0.68 kg; p≤0.05 versus 75:75 & 0:150). Post-prandial indices of cardiometabolic health and gut hormones, along with the expression of key genes in subcutaneous adipose tissue, were not statistically different between groups (p>0.05). Alternate-day fasting less effectively reduces body fat mass than a matched degree of daily energy restriction and without evidence of fasting-specific effects on metabolic regulation or cardiovascular health.
|Article number||598, eabd8034|
|Number of pages||15|
|Journal||Science Translational Medicine|
|Publication status||Published - 16 Jun 2021|