Strategies to increase vegetable or reduce energy and fat intake induce weight loss in adults

For obese individuals seeking to optimize health and well-being, healthy dietary strategies are important. Vegetables and fruits contribute to a healthy diet, and increased consumption may cause weight reduction by displacing foods high in energy and fat. The objective of this study was to determine if advising high vegetable (8 servings) and moderate fruit (2-3 servings) consumption would result in weight reduction in obese individuals. We compared this to advising a more traditional strategy of reducing daily energy intake by 500 kcal (2.1 MJ)/d and limiting energy from fat to ≤25%. A randomized study design was used. Subjects (age 21-50 y, n = 30/group) received food (2 meals + 1 snack/d, 5 d/wk) and education (2 group lessons/wk plus individual consultations as requested) for the first 3 mo. Weight and body composition were measured at baseline and after 3, 12, and 18 mo. Fasting serum lipid panel, insulin, glucose, hematocrit, and C-reactive protein were measured at baseline, 3, and 12 mo. Both groups lost weight after 3 mo (P = 0.0087 for high vegetable diet and P < 0.0001 for energy reduction diet), and the energy and fat reduction diet resulted in lower weight over time (P < 0.0001, treatment effect). Total cholesterol and cholesterol:HDL decreased after 3 mo in both groups (P ≤ 0.0061). Both strategies produced initial weight loss at 3 mo, but only the group following the caloric and fat reduction advice maintained weight loss at the 12- and 18-mo follow-up assessments. Nonetheless, the group following the high vegetable advice did not regain weight above baseline. In conclusion, traditional messages to reduce calories and fat are important, and increasing vegetable intake can assist individuals to maintain weight.