A time-efficient reduction of fat mass in 4 days with exercise and caloric restriction

Abstract

To determine whether a fast reduction in fat mass canbe achieved in 4 days by combining caloric restriction(CR: 3.2 kcal/kg body weight per day) with exercise(8-h walking+45-min arm cranking per day) to inducean energy deficit of∼5000 kcal/day, 15 overweight menunderwent five experimental phases: pretest, exercise+CR for 4 days (WCR), control diet+reduced exercise for3 days (DIET), and follow-up 4 weeks (POST1) and 1year later (POST2). During WCR, the diet consistedsolely of whey protein (n=8) or sucrose (n=7) (0.8 g/kgbody weight per day). After WCR, DIET, POST1, andPOST2, fat mass was reduced by a mean of 2.1, 2.8, 3.8,and 1.9 kg (P<0.05), with two thirds of this loss from thetrunk; and lean mass by 2.8, 1.0, 0.5, and 0.4 kg, respec-tively. After WCR, serum glucose, insulin, homeostaticmodel assessment, total and low-density lipoprotein cho-lesterol and triglycerides were reduced, and free fattyacid and cortisol increased. Serum leptin was reduced by64%, 50%, and 33% following WCR, DIET, and POST1,respectively (P<0.05). The effects were similar in bothgroups. In conclusion, a clinically relevant reduction infat mass can be achieved in overweight men in just 4 daysby combining prolonged exercise with CR.