Effects of nutrition education on weight gain prevention: a randomized controlled trial

BACKGROUND Body weight (BW) reduction through energy restriction is ineffective at impacting the obesity epidemic. Shifting from an obesity treatment to weight gain prevention focus may be more effective in decreasing the burden of adult obesity. METHODS This was a 1-year randomized controlled trial of weight gain prevention in healthy premenopausal women, aged 18-45 y, with a body mass index (BMI) of >18.5 kg/m(2). Eighty-seven women were randomized to a weight gain prevention intervention delivered by a registered dietitian (RDG) or counselor (CSG), or to a control (CON) group. Eighty-one women (mean ± SD, age: 31.4 ± 8.1 y; BW: 76.1 ± 19.0 kg; BMI: 27.9 ± 6.8 kg/m(2)) completed baseline testing and were included in intention-to-treat analyses; anthropometric, blood pressure, dietary intake and physical activity measurements and biochemical markers of health were measured every three months. Data were analyzed using repeated measures ANCOVA, with significance at P < 0.01. RESULTS Sixty-two percent of women met the weight gain prevention criteria (BW change within ±3 %) after one year; this did not differ by group assignment. Body fat % was lower in the RDG versus CSG and CON groups at all intervals (P < 0.001). Systolic blood pressure increased from month 6 to 9 and decreased from month 6 to 12 in the CON group (P < 0.001), with a significant group x time interaction (P < 0.01). Estimated carbohydrate intake (%) was higher in the RDG vs. CON group at month 9 (P < 0.01); fat intake (%) was lower in the RDG vs. CON group and CSG vs. CON group at months 3 and 9, respectively (P < 0.01). Estimated fruit intake (svgs/d) was higher in the RDG vs. CON group at months 3, 6, 9 and 12 (P < 0.01), and non-meat protein sources (svgs/d) was higher in the RDG vs. CSG and CON groups at month 3 (P < 0.001). Estimated energy, macronutrient and food group intakes did not change over time. CONCLUSIONS A majority of all participants maintained BW over one year and were able to do so regardless of whether they received nutrition education. Additional studies that include a variety of clinical outcomes are needed to evaluate further aspects of nutrition education on weight gain prevention and health status over the long term.