Effects of low-energy diet and exercise on body composition and bone mineral metabolism

• Project/Area Number: 04454583
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 家政学
• Research Institution: OSAKA CITY UNIVERSITY
• Principal Investigator: OKUDA Toyoko Osaka City University, Faculty of Human Life Science, Assistant Professor, 生活科学部, 助教授 (90047308)
• Project Period (FY): 1992 – 1993
• Project Status: Completed (Fiscal Year 1993)
• Budget Amount: ¥2,800,000 (Direct Cost: ¥2,800,000); Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000); Fiscal Year 1992: ¥2,000,000 (Direct Cost: ¥2,000,000)
• Keywords: Body composition / Fat-free mass / Body fat / Bone mineral density / Low-energy diet / Low-protein diet / Vegan / Ca balance / 低タンパク質 / エネルギー制限 / 骨強度 / 骨重量 / 骨中ミネラル / 自発運動

Research Abstract

The purpose of this study was to examine the effects of a low-energy, low-protein vegan diet for 6 months on bone mineral density (BMD), measured by dual-energy X-ray absorptiometry in middle-aged volunteers (three men and four women). The base-line BMD of the lumbar spine (L2-L4) was in the normal range for the subjects' age and sex except for two subjects, in whom it was low. After 6 month, the mean L2-L4 BMD and bone mineral content (BMC) had not decreased significantly. However, the L2-L4 BMC in one man, aged 30 years, had decreased by 9.0% of the base-line value. The total body BMC in two postmenopausal women had decreased by 14.2% and 13.8% of the base-line values after 6 months, but the mean total body BMC for the entire group did not decrease significantly during the 6 month on the vegan diet.
The purpose of this study was to examine the short-term effects of a low-energy, low-protein, vegan diet on the body composition of 31 middle-aged volunteers. The vegan diet contained 140g of brown rice, 500g o five varieties of leafy green vegetables, 500g of three kinds of roots, 80g of fruit, and 10g of salt daily. Before the start of the study, ten women were already on this vegan diet ("continuous" group) and 21 women were trying this diet for the first time or had tried this diet earlier once or several times ("non continuous" group). Body fat was measured by bioelectrical impedance. After 6 weeks, the "non continuous" group had greater weight loss (4.0 (〕SY.+-.〔) 0.4kg) than the "continuous" group (1.3 (〕SY.+-.〔) 0.5kg). Weight loss was 80.3 (〕SY.+-.〔) 8.5% from fat mass in the "non continuous" group. Body weight loss during 6 weeks was significantly associated with initial body weight, initial body fat mass, and the extent of decrease in the daily protein intake. The "non continuous" group used energy from body weight loss (698 (〕SY.+-.〔) 90kcal/day) for basal metabolism and physical activity. There was no excess loss of fat-free mass on this low-energy, low-protein, vegan diet for 6 weeks.