Epidemiological studies have revealed that soup consumption is associated with a lower risk of obesity. Moreover, intervention studies have reported that soup consumption aids in body-weight management. However, little is known about mechanisms that can explain these findings. The objective of the present study was to investigate associations between soup consumption and daily energy intake, dietary energy density (ED), nutrient intake and diet quality. Adults aged 19–64 years who participated in the National Health and Nutrition Examination Surveys during 2003–8 were included in the study. Soup consumers were identified from the first dietary recall using the United States Department of Agriculture food codes and combination food type from the dietary data. Compared with non-consumers (n 9307), soup consumers (n 1291) had a lower body weight (P= 0·002), a lower waist circumference (P= 0·001) and a trend towards a lower total energy intake (P= 0·087). Soup consumption was associated with a lower dietary ED (P< 0·001); this was independent of whether data on beverage or water consumption were included. Diet quality, as measured by the Healthy Eating Index 2005, was significantly better in soup consumers (P= 0·008). Soup consumption was also associated with a reduced intake of total fat and an increased intake of protein, carbohydrate and dietary fibre, as well as several vitamins and minerals (P< 0·05 for all). However, it was also associated with a higher intake of Na (P< 0·001). The relationship between soup consumption and body weight could be due to a reduced dietary ED and an improved diet quality. Consumers need to pay attention to their Na intake and choose low-Na products for a healthier diet.