The dietary customs of people of South Asian origin living in Britain are important determinants of health but have been relatively little studied. As part of the Coventry study of diabetes carried out in the Foleshill ward of the city, subjects undergoing oral glucose tolerance tests provided information on this aspect of lifestyle. A questionnaire was completed by all of the last 612 subjects undergoing testing. These included 304 of European origin, 118 Punjabi Sikhs, seventy-six Pakistani/Punjabi Moslems, twenty-eight Gujerati Moslems, twenty-five Punjabi Hindus and forty-seven Gujerati Hindus. There were no discernible differences in the dietary customs of those with normal glucose tolerance, impaired glucose tolerance and newly diagnosed diabetes. Subjects of South Asian origin ate significantly fewer meals per day than European subjects. Evening meal times were 2-3 h later among South Asians. Europeans ate less fruit but more vegetables and more brown rice than South Asians. Gujeratis ate more rice, fried snacks and white flour. Moslems were least likely to be vegetarians, to drink alcohol and to use home-made ghee and yoghurt, and Punjabi Sikhs and Hindus ate dhal more frequently than Pakistani Moslems, Gujerati Moslems or Hindus. Most South Asians ate Indian sweets and 'Western' snacks.