Objective: Our objective was to further elucidate the nutritional etiology of changes in body mass index (BMI; in kg/m(2)) and waist circumference by dietary intake pattern. We hypothesized that a healthy dietary pattern would lead to smaller changes in BMI and waist circumference than would other dietary patterns.

Design: Subjects were 459 healthy men and women participating in the ongoing Baltimore Longitudinal Study of Aging. Diet was assessed with the use of 7-d dietary records, from which 41 food groups were created and entered into a cluster analysis.

Results: Five dietary patterns were derived (healthy, white bread, alcohol, sweets, and meat and potatoes). The mean annual change in BMI was 0.30 +/- 0.06 for subjects in the meat-and-potatoes cluster and 0.05 +/- 0.06 for those in the healthy cluster (P < 0.01). The mean annual change in waist circumference was more than 3 times as great for subjects in the white-bread cluster (1.32 +/- 0.29 cm) as for those in the healthy cluster (0.43 +/- 0.27 cm) (P < 0.05).

Conclusions: Consuming a diet high in fruit, vegetables, reduced-fat dairy, and whole grains and low in red and processed meat, fast food, and soda was associated with smaller gains in BMI and waist circumference. Because foods are not consumed in isolation, dietary pattern research based on natural eating behavior may be useful in understanding dietary causes of obesity and in helping individuals trying to control their weight.