BackgroundAdults born preterm have higher levels of cardiometabolic risk factors than their term-born peers. Studies have suggested that at least those born smallest eat less healthily. We examined the association between early (<34 weeks) and late (34-36 weeks) preterm birth and diet and food preferences in adult age.MethodsParticipants of two cohort studies located in Finland completed a validated food frequency questionnaire (FFQ) at the age of 24 years to assess their usual diet and the adherence to healthy eating guidelines by using a recommended diet index (RDI). Overall, 182 were born early preterm, 352 late preterm, and 631 were term-born controls.ResultsYoung women born early preterm scored 0.77 points (95% confidence interval (CI) 0.03, 1.51) lower in RDI when adjusted for sex, age, parental education, and early-life confounders, indicating a lower quality of diet. There were no differences between young women born late preterm and controls or among men. When food groups were assessed separately, men born early preterm had lower consumption of fruits and berries than controls.ConclusionsYoung women born early preterm have poorer adherence to the healthy eating guidelines than their peers born at term. Differences in diet may contribute to an increased cardiometabolic risk among adults born early preterm.