The paper "Triglyceride Fats in Human Nutrition" by T. P. Hilditch, presented at the Fiftieth Scientific Meeting of the Nutrition Society, discusses the chemical constitution of natural fats and their role in human nutrition. The author provides a brief overview of the typical compositions of human and other mammalian fats, including depot, liver, and milk fats, as well as vegetable and marine animal fats. Hilditch explains that all natural fats are complex mixtures of mixed glycerides, but each individual mixed triglyceride follows a simple principle of even distribution of fatty acid groups between glycerol molecules. This principle is generally observed in most natural fats, except for animal depot fats and milk fats, which exhibit more complex structures due to biochemical modifications. The paper also covers the production of storage fat by animals, including the synthesis of fat from carbohydrates and the assimilation of dietary fats. It highlights that animals can convert carbohydrates into fat and lay down certain types of fat from dietary fats. The composition of fats synthesized in animals, such as pigs, sheep, and rats, is discussed, showing that palmitic, stearic, palmitoleic, and oleic acids are primarily synthesized. The paper further examines the assimilation of dietary fats, noting that fats must be fluid at body temperature to be fully digested. It also discusses the effects of different fatty acids on animal metabolism and the unique composition of depot fats when animals are fed specific vegetable oils. Finally, the paper addresses the hydrogenation of fatty oils, explaining that the composition of hydrogenated fats depends on the original fat and the degree of hydrogenation. It emphasizes the importance of considering the proportions of different fatty acids in natural fats for research on fat metabolism and suggests methods for analyzing complex mixtures of fatty acids.The paper "Triglyceride Fats in Human Nutrition" by T. P. Hilditch, presented at the Fiftieth Scientific Meeting of the Nutrition Society, discusses the chemical constitution of natural fats and their role in human nutrition. The author provides a brief overview of the typical compositions of human and other mammalian fats, including depot, liver, and milk fats, as well as vegetable and marine animal fats. Hilditch explains that all natural fats are complex mixtures of mixed glycerides, but each individual mixed triglyceride follows a simple principle of even distribution of fatty acid groups between glycerol molecules. This principle is generally observed in most natural fats, except for animal depot fats and milk fats, which exhibit more complex structures due to biochemical modifications. The paper also covers the production of storage fat by animals, including the synthesis of fat from carbohydrates and the assimilation of dietary fats. It highlights that animals can convert carbohydrates into fat and lay down certain types of fat from dietary fats. The composition of fats synthesized in animals, such as pigs, sheep, and rats, is discussed, showing that palmitic, stearic, palmitoleic, and oleic acids are primarily synthesized. The paper further examines the assimilation of dietary fats, noting that fats must be fluid at body temperature to be fully digested. It also discusses the effects of different fatty acids on animal metabolism and the unique composition of depot fats when animals are fed specific vegetable oils. Finally, the paper addresses the hydrogenation of fatty oils, explaining that the composition of hydrogenated fats depends on the original fat and the degree of hydrogenation. It emphasizes the importance of considering the proportions of different fatty acids in natural fats for research on fat metabolism and suggests methods for analyzing complex mixtures of fatty acids.