Influence of dietary protein upon the development of obesity, insulin resistance (IR) and energy metabolism (EM) in malnourished mice fed a high fat diet (HFD)

Aim To determine the influence of the dietary protein content upon obesity, IR and EM in malnourished mice fed a normal‐protein (NP‐HFD) or a low‐protein HFD diet (LP‐HFD). Methods Weaned male C57BL/6 mice were fed a protein‐restricted diet (6% protein ‐ R). After 6 weeks one group received a NP‐HFD (35% fat and 14% protein – RH) or LP‐HFD (35% fat and 6% protein – RRH). Results RH group had increased body weight (BW) (R=21.4±0.8; RH=30.7±1.0g) and perigonadal fat pad (R=1.6±0.08; RH=3.0±0.3%BW). RRH mice had lower BW (RRH=27.1±0.9g). RRH mice were protected from the hyperglycemia (R=65.8±3.1; RH=83.4±4.3; RRH=77.5±6.9mg/dL) and hyperinsulinemia (R=0.1±0.02; RH=0.3±0.03; RRH=0.1±0.03ng/mL) observed in RH mice. RH mice became glucose and insulin‐intolerant, which was improved in RRH mice (R=25.1±1.8; RH=40.7±3.2; RRH=29.9±3.1mg/dL.min/10 3 /R=3.0±0.2; RH=4.3±0.3; RRH=3.3±0.3 mg/dL.min/10 3 , respectively). Calorie intake was increased in HFD mice (R=10.1±0.79; RH=13.2±0.9; RRH=12.4±0.6kcal/day). During the dark period RH mice showed decreased energy expenditure which was prevented in RRH mice (R=136.7±4.0; RH=107.3±5.5; RRH=120.9±6.5 kcal/day/kg ^0.75 /10 3 ), despite the decreased ambulatory activity (R=24.3±2.8; RRH=16.2±0.9 arbitrary number/10 3 ) in this group. Conclusion RH mice became obese, hyperglycemic and IR, which was attenuated in RRH mice, possibly by regulation of the basal EM. Financial Support: FAPESP