Dietary energy density is associated with body mass index and waist circumference, but not with other metabolic risk factors, in free-living young Japanese women.

OBJECTIVE: Little is known about the relation of dietary energy density (kilocalories per gram) to metabolic risk factors, particularly in young adults and non-Western populations. We examined the cross-sectional associations between dietary energy density and several metabolic risk factors in free-living young Japanese women.
METHODS: The subjects were 1136 female Japanese dietetic students 18-22 y of age. Dietary energy density was estimated based on foods only, using a self-administered diet history questionnaire; before the present analysis, this measurement was validated against 16-d weighed dietary records in 92 Japanese women 31-69 y of age (Pearson's correlation coefficient 0.52). Body height and weight, from which body mass index (BMI) was derived, waist circumference, and blood pressure were measured, and fasting blood samples were collected for biochemical measurements.
RESULTS: Mean BMI was 21.3 kg/m(2) (standard deviation 2.7), mean waist circumference was 72.9 cm (standard deviation 7.1), and mean dietary energy density was 1.41 kcal/g (standard deviation 0.23). After adjustment for potential confounding factors, dietary energy density was positively associated with BMI (P for trend = 0.004). Dietary energy density also showed an independent and positive association with waist circumference (P for trend <0.0001). No significant associations were observed between dietary energy density and any of the other metabolic risk factors examined.
CONCLUSION: Dietary energy density was independently and positively associated with BMI and waist circumference, but not with other metabolic risk factors, in free-living young Japanese women who are not only lean but whose dietary energy density is also low compared with Western populations.