In the cross-sectional Lifestyle, Biomarkers, and Atherosclerosis study (LBA study) we have previously reported a high prevalence (15%) of homeostasis model assessment of insulin resistance (HOMA-IR) in Swedish, young adults. The aim of the present study was to report the dietary habits of subjects 18.0-25.9 years, and to associate dietary habits to body composition measures; body mass index (BMI), body fat (%), waist circumference and to HOMA-IR, a risk marker for diabetes.The subjects (577 women and 257 men) filled in a validated computerized food frequency questionnaire. The questionnaire was based on recommendations from the Swedish national food administration. To associate the dietary habits to BMI, body fat (%), waist circumference and to HOMA-IR the subjects were divided in two groups. Subjects "eating as recommended" and subjects "eating less/more than recommended".Recommended intake of fish and seafood ( < 0.05), fruit and vegetables ( < 0.001), and sweets ( < 0.05) were associated to lower HOMA-IR values compared to subjects not eating as recommended. When split by sex no difference in HOMA-IR was detected with recommended intake of fish and seafood, but women eating fish and seafood as recommended had less body fat (%) ( < 0.05) compared to women not eating fish and seafood as recommended. Recommended intake of fruit and vegetables was associated to lower HOMA-IR in women ( < 0.01), and in women and men to less body fat (%) ( < 0.05) compared to subjects not eating the recommended 500 g of fruit and vegetables per day. Both women and men with higher consumption of sweets than recommended had higher HOMA-IR ( < 0.05), but no difference in the body composition measures BMI, body fat (%) or waist circumference compared to subjects eating sweets as recommended.The results highlight the importance of reducing a high intake of sweets and to increase the intake of fish, fruit and vegetables, in young adults, to reduce the risk of future diabetes.