Metabolic response to short-term 4-day energy restriction in a controlled study

<p><b>OBJECTIVES</b>Metabolic rate is affected not solely by diet but also by environmental characteristics such as climate and seasonal changes in day length. In the present study, we conducted a controlled study in which we observed metabolic response to short-term energy restriction (ER).</p><p><b>MATERIALS AND METHODS</b>Thirty-two subjects were divided randomly into a slight ER group and a moderate ER group. The energy intake per day for slight ER vs moderate ER was 1462 kcal vs 1114 kcal. During the 4-day study periods, the same daily timetable, which consists of nutrition, exercise, sleeping and others, was imposed on both groups. The same environment was also provided to both groups.</p><p><b>RESULTS</b>After the 4-day ER, significant decreases in body weight and basal metabolic rate (BMR) were shown in both groups. The decrease in body weight was 2% of the baseline level in both groups, and the decreases in the BMR were 6% of baseline levels in the slight ER group and 13% in the moderate ER group. The decrease in BMR in the moderate ER group was significantly larger than that in the slight ER group.</p><p><b>CONCLUSIONS</b>In a controlled study of short-term ER, we observed a significant decrease in BMR. There was a positive association between the degree of ER and the reduction in BMR. Reductions in BMR were greater than those in body weight. It, thus, appears that the minimization of weight loss is due to dramatic decreases in BMR. This suggests the existence of metabolic resistance against ER.</p>

Metabolic Response to Short-Term 4-Day Energy Restriction in a Controlled Study

Objectives: Metabolic rate is affected not solely by diet but also by environmental characteristics such as climate and seasonal changes in day length. In the present study, we conducted a controlled study in which we observed metabolic response to short-term energy restriction (ER). Materials and Methods: Thirty-two subjects were divided randomly into a slight ER group and a moderate ER group. The energy intake per day for slight ER vs moderate ER was 1462 kcal vs 1114 kcal. During the 4-day study periods, the same daily timetable, which consists of nutrition, exercise, sleeping and others, was imposed on both groups. The same environment was also provided to both groups. Results: After the 4-day ER, significant decreases in body weight and basal metabolic rate (BMR) were shown in both groups. The decrease in body weight was 2% of the baseline level in both groups, and the decreases in the BMR were 6% of baseline levels in the slight ER group and 13% in the moderate ER group. The decrease in BMR in the moderate ER group was significantly larger than that in the slight ER group. Conclusions: In a controlled study of short-term ER, we observed a significant decrease in BMR. There was a positive association between the degree of ER and the reduction in BMR. Reductions in BMR were greater than those in body weight. It, thus, appears that the minimization of weight loss is due to dramatic decreases in BMR. This suggests the existence of metabolic resistance against ER.

Basal metabolism of Papua New Guinea highlanders / 体力科学

Basal metabolic rate (BMR) of 15 healthy male adult Papua New Guinea highlanders who live on a sweet-potato staple diet were examined by the indirect energy metabolims measuring method from October to December in both 1980 and 1982.<BR>In experment 1, 5 subjects followed a rice diet (RD) for 13 days and then switched to a low-protein rice diet (LPRD) for another 13 days. Mean RMR in the last 2-3 days of each diet period was 22.1±2.7 and 21.2±1.4 kcal/kg body weight/day (35.1±4.1 and 33.6±2.6 kcal/m<SUP>2</SUP>/hr), respectively.<BR>In experiment 2, 5 subjects followed a sweet-potato diet (S-PD) for 14 days and then switched to a low-protein sweet-potato diet (LPS-PD) for another 14 days. Mean BMR in the last 2-3 days of each diet period was 21.2±1.9 and 22.1±1.6 kcal/kg body weight/day (32.3±2.3 and 33.3±2.2 kcal/m<SUP>2</SUP>/hr), respectively.<BR>In experiment 3, 5 subjects were fed with a protein-free diet (PFD) for 11 days. Mean BMR in the last 2-3 days of this period was 25.3±2.2 kcal/kg body weight/day (38.3±4.0 kcal/m<SUP>2</SUP>/hr).<BR>Mean BMR measured within 2-3 days following the start of each of experiments 1, 2 and 3 was 24.7±2.3 kcal/kg body weight/day (38.0±3.3 kcal/m<SUP>2</SUP>/hr) in all subjects (15 persons) . We considered this value to be their usual BMR (control) .<BR>The subjects apparently followed a diet of similar content to the sweet-potato diet before the start of this experiment, but mean BMR of the S-PD group was significantly lower than the control value.<BR>On the oter hand, mean BMR of the RD and PFD groups, having a higher protein intake than obtained from their usual diet, was similar to the control value. We thought from the above results that protein intake levels do not influence BMR, although no clear explanation could be found for the results.<BR>In addition, we found that the Papua New Guinea highlanders showed high respiratory quotients (0.91-0.99) under such BMR measurement conditions, and we discussed this finding.