The modification of folate status was analysed in a group of sixty-seven overweight/obese women of childbearing age (20-35 years). Subjects were randomly assigned to one of two slightly hypocaloric diets: diet V (increased consumption of vegetables) or diet C (increased consumption of breakfast cereals). Dietetic, anthropometric and biochemical data were collected at the start of the study and again at 2 and 6 weeks. At 6 weeks a weight loss of 2.0 (sd 1.3) kg was achieved in V subjects and of 2.8 (sd 1.4) kg in C subjects (P < 0.05). At the start of the study, 64.2 % of all subjects had a folate intake of < 67 % of the recommended intake; this fell to just 3 % (7.14 % of V subjects and 0 % of C subjects) by week 6. Significant increases were only seen in C subjects in serum folate concentrations (both at 2 and 6 weeks), accompanied by a significant reduction in serum homocysteine (at week 6). Some 62.1 % of all subjects had serum folate concentrations of > or = 13.6 nmol/l (associated with a very low risk of neural tube defects) at the start of the study, while 87.0 % (85.2 % of V subjects and 88.9 % of C subjects) had concentrations of > or = 13.6 nmol/l at 6 weeks (P < 0.01). Increasing the relative consumption of vegetables/cereals in the context of a slightly hypocaloric diet may therefore be a good way to lose body weight. Breakfast cereals may be of special help with respect to folate status and serum homocysteine levels in overweight/obese young women following energy restriction diets.