Weight gain by hyperalimentation elevates C-reactive protein levels but does not affect circulating levels of adiponectin or resistin in healthy subjects.

OBJECTIVE Increase of resistin and/or reduction of adiponectin have been implicated in the development of insulin resistance following weight gain. We aimed to study this prospectively in humans. DESIGN Prospective and interventional with parallel control group. METHODS Twelve healthy men and six healthy women (age 26 ± 6.6 years) and an age-matched control group were recruited. Subjects in the intervention group aimed for a bodyweight increase of 5-15% by doubling the baseline caloric intake by eating at least two fast food-based meals a day in combination with adoption of a sedentary lifestyle for 4 weeks. RESULTS Bodyweight increased from 67.6 ± 9.1 to 74.0 ± 11 kg, P<0.001, by the intervention. Insulin levels increased (before: 27.4 ± 12 pmol/l, after: 53.0 ± 22 pmol/l, P=0.004), while plasma levels of adiponectin (before: 5038 ± 3736 ng/ml, after: 6739 ± 7949 ng/ml, P=0.18) and resistin (before: 21.8 ± 19 ng/ml, after: 14.4 ± 6.8 ng/ml, P=0.074) remained unchanged by the weight gain and were similar as in controls. On the other hand, leptin levels increased about threefold following the intervention (before: 5.7 ± 7.4, after: 16 ± 20 ng/ml, P=0.008), and also the inflammatory marker C-reactive protein (CRP) increased from 0.34 ± 0.44 to 0.71 ± 0.87 mg/l, P=0.03, when two outliers >10 mg/l were disregarded. CONCLUSIONS Hyperalimentation reduces insulin sensitivity when weight gain of 9% was combined with reduction of exercise. However, the levels of resistin and adiponectin were unaffected by the intervention, while CRP levels increased within this short time period suggesting that low-grade inflammation can occur early in the process of developing a metabolic syndrome.