Diet is of importance in the prevention of most chronic diseases. Dietary habits are measured regularly in most countries. In Switzerland data on groups and individuals are available, but a comprehensive dietary survey is still lacking. Since World War II an overall decrease in foods rich in complex carbohydrates and an increase in foods rich in fat available per capita of the population has been observed. Data on individuals show that 30%, i.e. 39% of men and 22% of women, in Switzerland are over-weight (BMI < or = 25). The percentages of energy intake as fat and sugar are higher, and the percentage of energy intake as complex carbohydrates lower than recommended. 7% of women and 6% of men consume hazardous amounts of alcohol (men > or = 60 g/day, women > or = 20 g/day). Marginal vitamin deficiencies are observed in various population groups for the vitamins B1, B2, B6, folic acid and vitamin C. Due to the fortification of salt and the widespread use of American wheat rich in selenium, iodine and selenium intake can be considered adequate. An insufficient intake of calcium is demonstrated in the elderly and an insufficient intake of calcium and iron in women. As a consequence of this nutritional situation, the first national nutritional guidelines have recently been published in Switzerland.