Thirty-seven people of different dietary habits-vegans, ovolactovegetarians, whole-food omnivores and average omnivores-were studied using nine-day weighed food intakes, clinical and laboratory assessments, standard psychology questionnaires, measurements of urinary cortisol and catecholamine levels and questionnaires on life-style and health factors. The vegan diet most clearly approximated current thinking on diet, as expressed in the NACNE Report, but was deficient in vitamin D, riboflavin, and vitamin B12. Cholesterol levels were significantly higher in both diet and serum in all groups compared with the vegans. There was no significant difference in social background, money spent on food, exercise, smoking, stress levels or psychological parameters between groups.