title: High-protein diet selectively reduces fat mass and improves glucose tolerance in Western-type diet-induced obese rats.
abstract: Obesity is an increasing health problem. Because drug treatments are limited, diets remain popular. High-protein diets (HPD) reduce body weight (BW), although the mechanisms are unclear. We investigated physiological mechanisms altered by switching diet induced obesity (DIO) rats from Western-type diet (WTD) to HPD. Male rats were fed standard (SD) or WTD (45% calories from fat). After developing DIO (50% of rats), they were switched to SD (15% calories from protein) or HPD (52% calories from protein) for up to 4 weeks. Food intake (FI), BW, body composition, glucose tolerance, insulin sensitivity, and intestinal hormone plasma levels were monitored. Rats fed WTD showed an increased FI and had a 25% greater BW gain after 9 wk compared with SD (P < 0.05). Diet-induced obese rats switched from WTD to HPD reduced daily FI by 30% on day 1, which lasted to day 9 (-9%) and decreased BW during the 2-wk period compared with SD/SD (P < 0.05). During these 2 wk, WTD/HPD rats lost 72% more fat mass than WTD/SD (P < 0.05), whereas lean mass was unaltered. WTD/HPD rats had lower blood glucose than WTD/SD at 30 min postglucose gavage (P < 0.05). The increase of pancreatic polypeptide and peptide YY during the 2-h dark-phase feeding was higher in WTD/HPD compared with WTD/SD (P < 0.05). These data indicate that HPD reduces BW in WTD rats, which may be related to decreased FI and the selective reduction of fat mass accompanied by improved glucose tolerance, suggesting relevant benefits of HPD in the treatment of obesity.
authors.affiliation: CURE/Digestive Diseases Research Center, Center for Neurobiology of Stress, Department of Medicine, Digestive Diseases Division at the University of California Los Angeles, and VA Greater Los Angeles Health Care System, Los Angeles, California;
authors.forename: Andreas
authors.initials: A
authors.lastname: Stengel
authors.forename: Miriam
authors.initials: M
authors.lastname: Goebel-Stengel
authors.forename: Lixin
authors.initials: L
authors.lastname: Wang
authors.forename: Eugenia
authors.initials: E
authors.lastname: Hu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Karasawa
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Pisegna
authors.forename: Yvette
authors.initials: Y
authors.lastname: Taché
mesh_terms: D050154:Adiposity / Q000187:drug effects*; D000818:Animals; D001835:Body Weight; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D008297:Male; D009765:Obesity / Q000178:diet therapy* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016896:Treatment Outcome
chemical_list: D004044:Dietary Proteins; D005947:Glucose
keywords: diet-induced obesity; food intake; gut hormones; high-protein diet