Concerns by the consumer over the relationships between diet and health are growing and there is increased recognition that the diseases of contemporary society can only be combatted by preventive measures. Dietary change is advocated in programmes designed to reduce the incidence of obesity, coronary heart disease and cancer. Recommendations relating to fat are particularly pertinent, with suggestions to reduce total fat consumption from approximately 40% of the energy to nearer 30% and to concentrate efforts on sources high in saturated fatty acids. This means less fat from animal sources, including milk. An immediate adoption of these recommendations is unlikely but increased media coverage is stimulating interest. Evidence from overseas indicates trends away from full-fat towards skimmed and semi-skimmed milks. In Britain, such products are not universally available and demand for milk is declining. However, dairies are increasing production of fat-reduced milks, particularly for supermarkets, and many consumers select these products in the interest of better health. The consequences for the milk producer may be predicted. An increased demand for fat-reduced rather than full-fat milk, coincident with a reduced demand for butter, will result in an accelerating reduction in the demand for milk fat. Under the new payments scheme, the prices paid for fat, protein and lactose must be influenced by market forces. Therefore, there is a strong possibility that, within the foreseeable future, the value of fat, relative to that of protein, is likely to fall. This would have profound implications for milk production and relevant research and development.