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: 21.8G +/- 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.