1. A study of the freely chosen diets of sixty-three men of the English middle class has been made by the “individual” method. All food was weighed for the period of a week, and the amounts of protein, animal protein, fat, carbohydrate, calories, calcium, total and available phosphorus and total and available iron in the individual diets have been calculated. Detailed and averaged results for the diets are given.
2. The average calorie intake was 3067 per day, but a very wide variation was observed (1772–4955 calories), and it is suggested that the adoption of 3000 calories as the requirement of an individual man may be most misleading.
3. There was a definite, but mathematically insignificant, decrease in calorie intake with increasing age. The individual variation at each age was so great, however, that no rules for the guidance of individuals as to their dietary requirements at different ages can possibly be formulated.
4. No significant correlation existed between calorie intake and body weight.
5. The proportion of calories derived from fat was higher than any figures previously recorded in this country. The proportion of calories derived from carbohydrate was correspondingly lower.
6. The total calcium, phosphorus and iron intakes were 0·87 g., 1·61 g. and 16·8 mg. per day respectively. 98 per cent, of the total phosphorus eaten was in an “available” form, while only 66 per cent, of the iron could be considered to be physiologically available.
7. A similar study has been carried out on six unemployed men, and the chemical composition of these diets is compared with that of employed, middle-class individuals.
Acknowledgments. The author wishes to thank Dr R. A. McCance for his enthusiastic encouragement and help, Miss M. Verdon-Roe for her assistance with the calculations, and all the subjects of the investigation for their willing co-operation. Part of the expense of this investigation were defrayed by a personal grant from the Medical Research Council.