Micronutrient quality of weight loss diets that focus on macronutrients: results from the A TO Z study

Abstract

Information on diet quality of alternative weight loss diets is limited. Our objective was to compare nutrient intake among overweight/obese women randomly assigned to the Atkins (n=73), Zone (n=73), LEARN (n=72), or Ornish (n=73) diets. Diet data were collected by 3‐day, unannounced, 24‐hour recall at baseline and after 8 weeks of diet instruction. Nutrient intakes were compared between groups at 8 weeks, and within groups for changes in risk of micronutrient deficiency (<2/3 RDA) between baseline and 8 weeks. At 8 weeks there were significant differences among groups for all macronutrients and many micronutrients (p<0.0001). Energy intake decreased from baseline for all 4 groups but was similar among groups. The proportion of individuals at risk of deficiency increased significantly (p<0.05) in the Atkins group for thiamin, folate, vitamin C, iron, and magnesium; in the LEARN group for vitamin E and calcium; and in the Ornish group for vitamins E and B12 and zinc. In contrast, for the Zone group the risk of deficiencies significantly decreased for vitamins A, C, E and K (p<0.05) with no significant increases in risk of deficiency. Weight loss diets that emphasize macronutrient composition should consider not only the weight loss outcomes, but also the adequacy of micronutrient intakes. This research was supported by NIH and the Community Foundation of Southeastern Michigan.