A total of 181 centrally obese men and women , with a mean ( range ) age of 42 y ( 20-66 y ) , body mass index ( in kg/m ( 2 ) ) of 30.2 ( 22.6-47 .3 ) , and waist circumference of 100 cm ( 80-138 cm ) were randomly assigned to receive either the NND ( high in fruit , vegetables , whole grains , and fish ) or an average Danish diet ( ADD ) for 26 wk .