Department of Health and Nutrition Sciences, Brooklyn College, City University of New York, Brooklyn, New York, USA.
Obesity (Silver Spring). 2010 Aug;18(8):1538-44. doi: 10.1038/oby.2009.466. Epub 2010 Jan 7.
Longitudinal effects of a very low-carbohydrate (VLC) and a calorie-matched high-carbohydrate (HC) weight reduction diet were compared in dietary obese Sprague-Dawley rats exhibiting impaired glucose tolerance and insulin resistance. Obese rats were divided into weight-matched groups: (i) VLC rats consumed an energy-restricted 5% carbohydrate, 60% fat diet for 8 weeks, (ii) HC rats consumed an isocaloric 60% carbohydrate, 15% fat diet, and (iii) HF rats consumed a high-fat diet ad libitum. HC and VLC rats showed similar reductions in body fat and hepatic lipid at the midpoint of the weight-reduction program, indicating effects due to energy deficit. At the end point, however, HC rats showed greater reductions in total and percent body fat, hepatic lipid and intramuscular lipid than did VLC rats, suggesting that diet composition induced changes in the relative efficiencies of the HC and VLC diets over time. HC rats showed marked improvement in glucose tolerance at the midpoint and end point, whereas VLC rats showed no improvement. Impaired glucose tolerance in VLC rats at the end point was due to insulin resistance and an attenuated insulin secretory response. Glucose tolerance in energy-restricted rats correlated negatively with hepatic and intramuscular lipid levels, but not visceral or total fat mass. These findings demonstrate that adaptations to diet composition eventually enabled HC rats to lose more body fat than VLC rats even though energy intakes were equal, and suggest that the elevated levels of hepatic and intramuscular lipid associated with VLC diets might predispose to insulin resistance and impaired glucose tolerance despite weight loss.
将能量限制的高脂肪（HF）饮食组与能量限制的低碳水化合物（VLC）饮食组和等热量的高碳水化合物（HC）饮食组进行比较，研究了肥胖、葡萄糖耐量受损和胰岛素抵抗的 Sprague-Dawley 大鼠的长期影响。肥胖大鼠被分为体重匹配的组：（i）VLC 大鼠摄入能量限制的 5%碳水化合物、60%脂肪饮食 8 周，（ii）HC 大鼠摄入等热量的 60%碳水化合物、15%脂肪饮食，和（iii）HF 大鼠自由摄入高脂肪饮食。HC 和 VLC 大鼠在体重减轻计划的中点显示出相似的体脂和肝脂质减少，表明这是由于能量不足的影响。然而，在终点时，HC 大鼠显示出比 VLC 大鼠更大的总体脂和体脂百分比、肝脂质和肌内脂质减少，表明随着时间的推移，饮食组成诱导了 HC 和 VLC 饮食的相对效率的变化。HC 大鼠在中点和终点显示出葡萄糖耐量的显著改善，而 VLC 大鼠则没有改善。VLC 大鼠在终点时葡萄糖耐量受损是由于胰岛素抵抗和胰岛素分泌反应减弱。能量限制大鼠的葡萄糖耐量与肝和肌内脂质水平呈负相关，但与内脏或总脂肪量无关。这些发现表明，饮食组成的适应最终使 HC 大鼠能够比 VLC 大鼠减掉更多的体脂，尽管能量摄入相等，并且表明与 VLC 饮食相关的升高的肝和肌内脂质水平可能导致胰岛素抵抗和葡萄糖耐量受损，尽管体重减轻。
