High-protein diet selectively reduces fat mass and improves glucose tolerance in Western-type diet-induced obese rats.
Study Goal
The researchers aimed to investigate the physiological mechanisms by which a high-protein diet (HPD) reduces body weight in diet-induced obese rats switched from a Western-type diet.
Results Summary
Switching obese rats from a Western-type diet to HPD reduced food intake by 30% initially and 9% by day 9, decreased body weight, and led to a 72% greater fat mass loss compared to controls, while lean mass remained unchanged. HPD also improved glucose tolerance and increased levels of satiety hormones like pancreatic polypeptide and peptide YY.
Population
Male diet-induced obese rats
Effective Dosage
52% of calories from protein
Duration
4 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Western-type diet | increase | Food intake | rats | - | showed an increased | #1 |
Western-type diet | increase | body weight gain | rats | 25% | had a 25% greater | #2 |
High-protein diet | decrease | Food intake | diet-induced obese rats switched from WTD | 30% | reduced daily FI by 30% | #3 |
High-protein diet | decrease | body weight | diet-induced obese rats switched from WTD | - | decreased | #4 |
High-protein diet | decrease | fat mass | WTD/HPD rats | 72% | lost 72% more | #5 |
High-protein diet | no change | lean mass | WTD/HPD rats | - | was unaltered | #6 |
High-protein diet | decrease | blood glucose | WTD/HPD rats | - | had lower | #7 |
High-protein diet | increase | pancreatic polypeptide and peptide YY | WTD/HPD rats | - | increase ... was higher | #8 |
High-protein diet | decrease | body weight | WTD rats | - | reduces | #9 |
High-protein diet | decrease | Food intake | WTD rats | - | decreased | #10 |
High-protein diet | decrease | fat mass | WTD rats | - | selective reduction | #11 |
High-protein diet | increase | glucose tolerance | WTD rats | - | improved | #12 |
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.