In the early 1930s, after obtaining her PhD on the carbohydrates in apples, Dr Elsie Widdowson embarked on a postgraduate course in dietetics at King’s College of Household and Social Science, London. During the hospital training element of this course at St Bartholomew’s Hospital, she was appalled at the inaccuracy of the food compositional data being used to formulate medically-prescribed diets. She resolved to change matters, and after she had joined Dr McCance’s team she realized that they had already obtained sufficient new analytical data on the majority of the food groups to form the basis of completely new tables.

Dr Widdowson and Professor McCance always expressed a great deal of interest in the inter-individual variability in their scientific data considering that extreme values often provided the most revealing results. Their interest developed as a result of Dr Widdowson’s studies of the individual diets of men, women and children conducted in the 1930s; she later used the phrase ‘nutritional individuality’ to describe between-individual variability in intake and expenditure (Widdowson, 1962). This paper continues Dr Widdowson’s theme of individual variability. It focuses on recent data which describe between-individual differences in daily energy expenditure, particularly the extremes, and also on the insights these have given into the measurements of energy intake (EI).

It was nearly 120 years ago that the physiologist Claude Bernard proposed that for an organism to function optimally the component cells must be surrounded by a medium of closely regulated composition (‘La fixité du milieu interne est la condition de la vie libre’). Homeostasis is the term used today to describe this phenomenon, being first coined by Walter B. Cannon in 1929 (Hardy, 1976). This is the underlying physiological principle that explains the relative chemical constancy of the body, including inorganic nutrients such as Fe.

It is by no means an exaggeration to say that Dr Widdowson is one of the pioneers of body composition research and her studies in the 1940s and 1950s have laid the foundations of body composition science today. These have included both animal and human studies, although this paper will focus only on the latter. Together with Professor McCance and Christine Spray she was responsible for the analysis of three entire adult human cadavers and that of a 4-year-old child (Widdowson et al. 1951). Further work with Dr Dickerson explored the composition of specific tissues and organs of the body (Widdowson & Dickerson, 1964). These studies provide some of the best direct data on human body composition. Moreover the findings from this work form the basis of the indirect techniques which are used so widely today.

This quotation is perhaps especially appropriate when considering the extensive contributions made by Professor McCance and Dr Widdowson to the field of early nutrition and later development. A detailed knowledge of their work in this area is of undoubted value both in interpreting many recent findings and in the design of new investigations. The first part of this paper presents a brief overview of some of their most significant studies. Their implications at both the fundamental and applied levels are then discussed, especially in relation to the role of nutrition in health and disease. Finally, potential mechanisms by which development may be modified by early nutrition are considered.

In 1986, in her paper, ‘Animals in the service of human nutrition’, celebrating the award of the E. V. McCollum International Lectureship in Nutrition, Dr Elsie Widdowson observed: ‘Animals have served human nutrition well over the past century.... They are still of great service in human nutrition and may be more essential in the future as proper animal models for human diseases are discovered’. Ten years on, those animal models are an integral part of nutrition research and are providing fundamental tools to study the effects of diet on many of the major diseases of the Western world, including cardiovascular disease, obesity and cancer. Many of these models have been developed through the use of recombinant DNA technology and the expression of normal or mutated genes in the genome of transgenic mice.

Zoo animal nutritionists need to make decisions about diet composition for a wide variety of vertebrate species, including those with very specialized diets (dietary specialists). For some zoo species it is common to refer to the published literature on the nutrient requirements of analogous domestic animals, such as cattle, horses and cats, as well as human beings (Allen & Oftedal, 1996). When this information is combined with knowledge of natural history, feeding patterns, composition of foods consumed in the wild and gastrointestinal tract morphology, it is possible to develop a sound foundation for a successful feeding programme for many zoo animals.