title: Energy balance and hypothalamic effects of a high-protein/low-carbohydrate diet.
abstract: Diets high in fat or protein and extremely low in carbohydrate are frequently reported to result in weight loss in humans. We previously reported that rats maintained on a low-carbohydrate-high fat diet (LC-HF) consumed similar kcals/day as chow (CH)-fed rats and did not differ in body weight after 7 weeks. LC-HF rats had a 45% decrease in POMC expression in the ARC, decreased plasma insulin, and increased plasma leptin and ghrelin. In the present study we assessed the effects of a low-carbohydrate-high-protein diet (HP: 30% fat, 65% protein, and 5% CHO) on body weight, caloric intake, plasma hormone levels and hypothalamic gene expression. Male rats (n=16) were maintained on CH or HP for 4 weeks. HP rats gained significantly less weight than CH rats (73.4+/-9.4 and 125.0+/-8.2 g) and consumed significantly less kcals/day (94.8+/-1.5 and 123.6+/-1.1). Insulin was significantly reduced in HP rats (HP: 1.8+/-0.6 vs. CH: 4.12+/-0.8 ng/ml), there were no differences between groups in plasma leptin and plasma ghrelin was significantly elevated in HP rats (HP: 127.5+/-45 vs. CH: 76.9+/-8 pg/ml). Maintenance on HP resulted in significantly increased ARC POMC (HP: 121+/-10.0 vs. 100+/-5.9) and DMH NPY (HP: 297+/-82.1 vs. CH: 100+/-37.7) expression compared to CH controls. These data suggest that the macronutrient content of diets differentially influences hypothalamic gene expression in ways that can affect overall intake.
authors.affiliation: Purdue University, Department of Psychological Sciences, United States. kkinzig@psych.purdue.edu
authors.forename: Kimberly P
authors.initials: KP
authors.lastname: Kinzig
authors.forename: Sara L
authors.initials: SL
authors.lastname: Hargrave
authors.forename: Jayson
authors.initials: J
authors.lastname: Hyun
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Moran
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D001522:Behavior, Animal; D001835:Body Weight / Q000187:drug effects; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004435:Eating / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects*; D005518:Food Preferences / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D054439:Ghrelin / Q000097:blood; D007031:Hypothalamus / Q000187:drug effects*; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D008297:Male; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D054439:Ghrelin; D007328:Insulin; D020738:Leptin; D009478:Neuropeptide Y; D011333:Pro-Opiomelanocortin; D020155:3-Hydroxybutyric Acid