A high fat diet failed to enhance the progressive development of the metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) in middle‐aged non human primates (NHPs)

NHPs, with a lifetime on a "healthy" low fat diet, nevertheless, frequently develop obesity, MS and T2DM, fully like those in humans. The aim of the present study was to determine whether a high fat/high cholesterol diet (HFHC) vs the standard low fat/low cholesterol diet (LFLC)) would enhance the development of MS in middle‐aged NHPs. The diets were: HFHC 35% kcal CHO, 45% fat, and 20% protein, 0.25% cholesterol by wt (Research Diets, Inc. RD #D07110401); and LFLC: 68%, 13%, 18%, 0.008% ; respectively (LabDiet 5038). 28 NHPs, 50% male, were fed ad libitum either HFHC or LFLC. 7 of the 14 NHP tolerated the HFHC diet for a minimum of 3 months, and showed no changes in total calorie intake, body weight, triglyceride or HDL cholesterol levels, but had significantly increased total and LDL cholesterol compared to baseline (TC: 357 ± 39 vs 166 ± 8.4 mg/dl; p<0.001) and to the LFLC diet (163.7 ± 9.9 mg/dl; p<0.001). However, 7 monkeys fed the HFHC developed intolerance to the diet 2 to 10 days after its initiation. Early lipid changes in the diet intolerant were not different from those of the HFHC tolerant monkeys, and there were no changes in serum chemistry values. Conclusion The high fat/high cholesterol diet had no effect to increase calorie intake or to produce weight gain, and altered none of the features of MS, but significantly increased total plasma cholesterol and LDL cholesterol in NHPs. Supported by NIA HHSN2532008002C and RD, Inc.