WEIGHT-LOSS IS GREATER WITH CONSUMPTION OF LARGE MORNING MEALS AND FAT-FREE MASS IS PRESERVED WITH LARGE EVENING MEALS IN WOMEN ON A CONTROLLED WEIGHT-REDUCTION REGIMEN

The purpose of this study was to determine whether meal ingestion patt ern [large morning meals (AM) vs. large evening meals (PM)] affects ch anges in body weight, body composition or energy utilization during we ight loss. Ten women completed a metabolic ward study of 3-wk weight s tabilization followed by 12 wk of weight toss with a moderately energy restricted diet [mean energy intake +/- SD = 107 +/- 6 kJ/(kg . d)] a nd regular exercise. The weight loss phase was divided into two 6-wk p eriods. During period 1, 70% of daily energy intake was taken as two m eals in the AM (n = 4) or in the PM (n = 6). Subjects crossed over to the alternate meal time in period 2. Both weight loss and fat-free mas s loss were greater with the AM than the PM meal pattern: 3.90 +/- 0.1 9 vs. 3.27 +/- 0.26 kg/6 wk, P < 0.05, and 1.28 +/- 0.14 vs. 0.25 +/- 0.16 kg/6 wk, P < 0.001, respectively. Change in fat mass and loss of body energy were affected by order of meal pattern ingestion. The PM p attern resulted in greater loss of fat mass in period 1 (P < 0.01) but not in period 2. Likewise, resting mid-afternoon fat oxidation rate w as higher with the PM pattern in period 1 (P < 0.05) but not in period 2, corresponding with the fat mass changes. To conclude, ingestion of larger AM meals resulted in slightly greater weight loss, but ingesti on of larger PM meals resulted in better maintenance of fat-free mass. Thus, incorporation of larger PM meals in a weight loss regimen may b e important in minimizing the loss of fat-free mass.