other preobese models that have been used to study the potential role of energy expenditure on the cause of obesity include examination of ethnic groups at higher risk of obesity (e.g.,mohawk indians and african-americans). in mohawk children in upstate new york, the prevalence of obesity haas been estimated as 44% total energy expenditure,however, was 8.5% hihher in mohawk compared with white children living in vermont because of a 37% higher physical activity-related energy expenditure in the mohawk children. in african-american children, a 14% lower resting energy expenditure was found compared with white children, adjusting for age, gender, weight, fat-free mass,and fat mass. among girls aged 6 to 16 years, lower resting energy expenditure was also found in african-americans than in whites, adjusting for body weight and lean body mass. several other studies have shown a significantly lower energy expenditure in african-american compared with white subjects independent of ethnic differences in body composition. this finding has been shown across the life span but has not been observed in all studies. it remains to be seen whether this ethnic difference is a contributing factor to the increased prevalence of obesity among african-americans.