The Hypertension Prevention Trial (HPT) was a multicenter randomized trial designed to assess the effects of long-term dietary changes on blood pressure in a normotensive population (diastolic blood pressure greater than or equal to 78 but less than 90 mm Hg) for a period of 3 years. The dietary treatments were reduction of sodium intake, increase of potassium intake, and decrease of energy intake. Estimates of changes in food intake were made by comparing 24-hour food records of the treatment and control participants. The participants in the treatment groups reported sodium intakes that were 30% to 40% lower than those of the controls. The restriction was achieved mainly by reducing intake of salt, meats, and grain products. Meats and grain products were still a major source of total sodium intake after treatment (41% to 47%), perhaps because of continued use of processed foods. Potassium intake was reported to be 16% to 25% higher in the treatment groups than in the controls, the increase achieved largely through increased consumption of fruits, with a lesser contribution from vegetables. Participants with higher initial body weights reported smaller increases in fruit and vegetable consumption than participants of normal weight, perhaps because of concerns about weight gain. Energy intake in the weight loss groups was 8% to 11% less than that of the controls. Men reported success in restricting calories from meats, dairy products, fats, beverages, and sugars. Women were less successful in restricting calories from most food groups.(ABSTRACT TRUNCATED AT 250 WORDS)