A computational method for constructing individually acceptable diets by modifying a chosen diet to meet nutritional requirements is described. The effects on food quantities of imposing different nutrient requirements on a sample diet are demonstrated and techniques which can ensure the acceptability to the individual of the modified diet are described. The starting point in the calculation is the person's current dietary intake. This is modified using linear programming methods which make the smallest changes to the food quantities to meet specific targets. Sequential modification can be used to identify changes that are acceptable to the individual. The computer program has been developed in collaboration with practising dietitians and is in use in some leading UK hospitals.