Robert H Lustig, Kathleen Mulligan, Susan M Noworolski, Viva W Tai, Michael J Wen, Ayca Erkin-Cakmak, Alejandro Gugliucci, Jean-Marc Schwarz

Dietary fructose is implicated in metabolic syndrome, but intervention studies are confounded by positive caloric balance, changes in adiposity, or artifactually high amounts. This study determined whether isocaloric substitution of starch for sugar would improve metabolic parameters in Latino (n = 27) and African-American (n = 16) children with obesity and metabolic syndrome. Participants consumed a diet for 9 days to deliver comparable percentages of protein, fat, and carbohydrate as their self-reported diet; however, dietary sugar was reduced from 28% to 10% and substituted with starch. Participants recorded daily weights, with calories adjusted for weight maintenance. Participants underwent dual-energy X-ray absorptiometry and oral glucose tolerance testing on Days 0 and 10. Biochemical analyses were controlled for weight change by repeated measures ANCOVA. Reductions in diastolic blood pressure (-5 mmHg; P = 0.002), lactate (-0.3 mmol/L; P < 0.001), triglyceride, and LDL-cholesterol (-46% and -0.3 mmol/L; P < 0.001) were noted. Glucose tolerance and hyperinsulinemia improved (P < 0.001). Weight reduced by 0.9 ± 0.2 kg (P < 0.001) and fat-free mass by 0.6 kg (P = 0.04). Post hoc sensitivity analysis demonstrates that results in the subcohort that did not lose weight (n = 10) were directionally consistent. Isocaloric fructose restriction improved surrogate metabolic parameters in children with obesity and metabolic syndrome irrespective of weight change.