Low- and high-carbohydrate diets: body composition differences in rats

Obes Res. 2005 Oct;13(10):1651-60. doi: 10.1038/oby.2005.203.

Abstract

Objective: To determine differences in adipose tissue mass, cell size, and lipid metabolism transcripts and differences in composition of body weight loss and energy expenditure (EE) after isoenergetic, energy-restricted intake of low-carbohydrate/high-fat/high-protein (LC) and high-carbohydrate/low-fat/moderate-protein (HC) diets.

Research methods and procedures: Ten-week old female Sprague-Dawley rats were fed a high-fat diet ad libitum for 8 weeks to induce weight gain and fat deposition. Weight-matched rats were then assigned to isoenergetic LC (Atkins) and HC (American Dietary Association Exchange) diets for 10 weeks at 65% of ad libitum energy intake.

Results: There was no significant difference in the serum lipid profiles or amount of body weight lost between the HC and LC groups, whereas a higher insulin sensitivity index (p < 0.01) resulted from the HC compared with the LC diet. Compared with the post-restriction LC group, the HC group demonstrated (p < 0.05) higher EE during active hours, lower mRNA levels for the lipogenic genes peroxisome proliferator-activated receptor gamma2, lipoprotein lipase, and, adipocyte fatty acid binding protein, decreased adipocyte cell volume, and decreased fat mass.

Discussion: Results indicated down-regulation of lipogenic genes, decreased fat mass, and, therefore, improved body composition in the post-restriction HC compared with the LC group. The small mean differences between the two diet groups (p = 0.11) in 24-hour EE over the 10 weeks of diet intervention would account for the majority of the lower mean body weights in the post-restriction HC group. These data suggest that macronutrient composition of the diet influences body composition and indicate a distinction between HC and LC diets.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Body Composition*
  • Body Weight
  • DNA Primers
  • Dietary Carbohydrates / administration & dosage*
  • Energy Metabolism
  • Fatty Acid-Binding Proteins / genetics
  • Female
  • Insulin Resistance
  • Lipoprotein Lipase / genetics
  • PPAR gamma / genetics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • DNA Primers
  • Dietary Carbohydrates
  • Fatty Acid-Binding Proteins
  • PPAR gamma
  • RNA, Messenger
  • Lipoprotein Lipase