Larson-Meyer D Enette, Heilbronn Leonie K, Redman Leanne M, Newcomer Bradley R, Frisard Madlyn I, Anton Steve, Smith Steven R, Alfonso Anthony, Ravussin Eric
Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
Diabetes Care. 2006 Jun;29(6):1337-44. doi: 10.2337/dc05-2565.
The purpose of this article was to determine the relationships among total body fat, visceral adipose tissue (VAT), fat cell size (FCS), ectopic fat deposition in liver (intrahepatic lipid [IHL]) and muscle (intramyocellular lipid [IMCL]), and insulin sensitivity index (S(i)) in healthy overweight, glucose-tolerant subjects and the effects of calorie restriction by diet alone or in conjunction with exercise on these variables.
Forty-eight overweight volunteers were randomly assigned to four groups: control (100% of energy requirements), 25% calorie restriction (CR), 12.5% calorie restriction +12.5% energy expenditure through structured exercise (CREX), or 15% weight loss by a low-calorie diet followed by weight maintenance for 6 months (LCD). Weight, percent body fat, VAT, IMCL, IHL, FCS, and S(i) were assessed at baseline and month 6.
At baseline, FCS was related to VAT and IHL (P < 0.05) but not to IMCL. FCS was also the strongest determinant of S(i) (P < 0.01). Weight loss at month 6 was 1 +/- 1% (control, mean +/- SE), 10 +/- 1% (CR), 10 +/- 1% (CREX), and 14 +/- 1% (LCD). VAT, FCS, percent body fat, and IHL were reduced in the three intervention groups (P < 0.01), but IMCL was unchanged. S(i) was increased at month 6 (P = 0.05) in the CREX (37 +/- 18%) and LCD (70 +/- 34%) groups (P < 0.05) and tended to increase in the CR group (40 +/- 20%, P = 0.08). Together the improvements in S(i) were related to loss in weight, fat mass, and VAT, but not IHL, IMCL, or FCS.
Large adipocytes lead to lipid deposition in visceral and hepatic tissues, promoting insulin resistance. Calorie restriction by diet alone or with exercise reverses this trend.
本文旨在确定健康超重且糖耐量正常的受试者体内总体脂肪、内脏脂肪组织（VAT）、脂肪细胞大小（FCS）、肝脏异位脂肪沉积（肝内脂质[IHL]）和肌肉异位脂肪沉积（肌细胞内脂质[IMCL]）与胰岛素敏感性指数（S(i)）之间的关系，以及单纯饮食热量限制或联合运动对这些变量的影响。
48名超重志愿者被随机分为四组：对照组（能量需求的100%）、25%热量限制（CR）组、12.5%热量限制 + 通过结构化运动增加12.5%能量消耗（CREX）组，或通过低热量饮食减重15%后维持体重6个月（LCD）组。在基线和第6个月时评估体重、体脂百分比、VAT、IMCL、IHL、FCS和S(i)。
在基线时，FCS与VAT和IHL相关（P < 0.05），但与IMCL无关。FCS也是S(i)的最强决定因素（P < 0.01）。第6个月时的体重减轻分别为1±1%（对照组，均值±标准误）、10±1%（CR组）、10±1%（CREX组）和14±1%（LCD组）。三个干预组的VAT、FCS、体脂百分比和IHL均降低（P < 0.01），但IMCL未改变。在CREX组（37±18%）和LCD组（70±34%）中，第6个月时S(i)增加（P = 0.05）（P < 0.05），CR组有增加趋势（40±20%，P = 0.08）。S(i)的改善与体重、脂肪量和VAT的减少相关，但与IHL、IMCL或FCS无关。
大脂肪细胞导致内脏和肝脏组织中的脂质沉积，促进胰岛素抵抗。单纯饮食热量限制或联合运动可逆转这一趋势。
