Background: Little is known about diet quality with a reduced-energy, low-fat, partial meal replacement plan, especially in individuals with type 2 diabetes. The Action for Health in Diabetes (Look AHEAD) trial implemented a partial meal replacement plan in the Intensive Lifestyle Intervention. Objective: To compare dietary intake and percent meeting fat-related and food group dietary recommendations in Intensive Lifestyle Intervention and Diabetes Support and Education groups at 12 months. Design: A randomized controlled trial comparing Intensive Lifestyle Intervention with Diabetes Support and Education at 0 and 12 months. Participants/setting: From 16 US sites, the first 50% of participants (aged 45 to 76 years, overweight or obese, with type 2 diabetes) were invited to complete dietary assessments. Complete 0- and 12-month dietary assessments (collected between 2001 and 2004) were available for 2,397 participants (46.6% of total participants), with 1,186 randomized to Diabetes Support and Education group and 1,211 randomized to Intensive Lifestyle Intervention group. Main outcome measures: A food frequency questionnaire assessed intake: energy; percent energy from protein, fat, carbohydrate, polyunsaturated fatty acids, and saturated fats; trans-fatty acids; cholesterol; fiber; weekly meal replacements; and daily servings from food groups from the Food Guide Pyramid. Statistical analyses performed: Mixed-factor analyses of covariance, using Proc MIXED with a repeated statement, with age, sex, race/ethnicity, education, and income controlled. Unadjusted χ2 tests compared percent meeting fat-related and food group recommendations at 12 months. Results: At 12 months, Intensive Lifestyle Intervention participants had a significantly lower fat and cholesterol intake and greater fiber intake than Diabetes Support and Education participants. Intensive Lifestyle Intervention participants consumed more servings per day of fruits; vegetables; and milk, yogurt, and cheese; and fewer servings per day of fats, oils, and sweets than Diabetes Support and Education participants. A greater percentage of Intensive Lifestyle Intervention participants than Diabetes Support and Education participants met fat-related and most food group recommendations. Within Intensive Lifestyle Intervention, a greater percentage of participants consuming two or more meal replacements per day than participants consuming less than one meal replacement per day met most fat-related and food group recommendations. Conclusions: The partial meal replacement plan consumed by Intensive Lifestyle Intervention participants was related to superior diet quality.