Abstract 17578: Reductions in Systematic Inflammation After a Low-Carbohydrate Diet versus a Low-Fat Diet Each Combined with Exercise

Abstract

Background: Systemic inflammation is a mechanism by which obesity increases CVD risk. Though weight loss generally improves inflammation, a concern about low-carbohydrate (CHO) diets is that a concomitant higher fat intake may adversely impact CV health. We hypothesized that similar improvements in markers of inflammation would be observed when weight loss is induced through a low-CHO diet compared with a low fat diet.

Methods: Overweight or obese but otherwise healthy persons, 30-65 years old, were randomly assigned to 6-months of an isocaloric low-CHO or low-fat diet. Each group also participated in exercise training 3 times per week. The primary outcomes were high sensitivity C-reactive protein (hsCRP), interleukin 6 (hsIL-6), and tumor necrosis factor-alpha (hsTNF-a). Also measured were body weight, BMI, total body and trunk fat by dual energy x-ray absorptiometry, and peak oxygen uptake (VO₂) during treadmill testing.

Results: Sixty subjects (low-CHO group: n=31,74% women; low-fat group, n=29, 72% women) completed the study. There were no group baseline differences in the following and the combined values are: age, 50.0±8.7 years; weight, 97.1±14.9 kg; BMI, 34.2±3.8 kg/m²; total body fat, 43.3±7.2%; trunk fat, 46.4±5.7%; and peak VO₂, 25.8± 5.3 ml/kg/min; hsCRP, 5.2±5.0 mg/L; hsIL-6, 1.9±4.6 pg/mL; hsTNFa, 4.5±1.1 pg/mL. At 6 months, the low-CHO vs low-fat subjects had a greater drop in weight, -13.1±5.0 vs. -8.2± 4.7 kg, p<0.001; BMI, -4.7±2.0 vs -2.9±1.7, p<0.001; body fat, -6.8±4.5 vs -4.0±3.9%, p>0.02. The groups did not differ in reduction of trunk fat; overall loss - 5.5±5.7%, or the increase in peak VO₂, overall gain; 6.0±4.3 ml/kg/min, both p<0.001 vs baseline. At 6 months, the groups did not differ in the reduction in hsCRP, overall drop, -1.8±3.1 mg/L, p<0.0001; hsIL-6, -0.48±1.59 pg/mL, p<0.03; and hsTNFa, -0.64±0.96 pg/mL, p<0.0001.

Conclusions: Both groups reduced systemic inflammation, reduced total and central obesity, and increased fitness, with greater losses in weight, BMI, and total body fat occurring in the low-CHO group. A key finding was no group difference in the reduction in systemic inflammation, suggesting that a lifestyle intervention that includes a low-CHO diet improved inflammatory responses similar to a low-fat diet.