THE HIGH-FAT PHENOTYPE - IS LEPTIN INVOLVED IN THE ADAPTIVE RESPONSE TO A HIGH-FAT (HIGH-ENERGY) DIET

OBJECTIVE: To investigate physiological differences which could influe nce the balance between energy expenditure and energy intake, between habitual high-fat (HF) and low-fat (LF) consumers and the potential fo r weight gain. SUBJECTS: Ten HF and nine LF consumers, all young, lean males (% energy from fat 45.4 and 31.8, respectively). MEASUREMENTS: Habitual dietary variables (from the food frequency questionnaire, FFQ ), body mass index (BMI), % body fat (% BF, measured by impedance), fa sting concentrations of plasma leptin, glucose and triglycerides. RESU LTS: HF and LF subjects (selected for their fat intake) did not differ significantly in BMI or % BF. HF subjects had significantly higher co ncentrations of plasma leptin and lower concentrations of plasma gluco se than LF subjects. In all subjects, concentrations of fasting plasma leptin correlated significantly with BMI, % BF and fat mass; differen ce in leptin between groups remained significant when BMI and % BF wer e used as covariants. Leptin significantly correlated with dietary var iables; particularly dietary fat (% energy and g) and inversely with d ietary carbohydrate (% energy), but showed no correlation with dietary protein or total energy intake. CONCLUSION: Significant differences i n concentrations of fasting plasma leptin have been observed between l ean male HF and LF consumers. These findings suggest that the differen ce in leptin concentrations could be associated with a metabolic: adap tation which could help to offset the weight inducing properties of hi gh fat (high energy) diets.