Why Has the BMI gone up so drastically in the last 35 years?

We attempted to answer the following questions: Why has the body mass index (BMI) increased so dramatically in the last 35 years? Are some food groups or additives more responsible than others?

Data for per capita food production available for consumption after spoilage for different food groups and additives from the US Department of Agriculture were used as independent variables to predict BMI increases. The heights and weights were taken from the Centers for Disease Control and the US Census Bureau for the years 1970 to 2004.

The additives of fats and sugars in combination, not separately, best predicted increases in BMI accounting for 97% of the variance in the linear regression analyses. When all food groups were entered into regressions to predict increases in BMI, fats and sugars in combination accounted for 96% of the variance for women and 97% for men, with the other food groups adding very little. Path analyses showed that fat and sweeteners had direct effects on BMI and were also the mediators of increased caloric consumption.

In line with the major physiological theories emphasizing palatability as the addictive stimulus in models of incentives and addiction, fats and sugars in combination rather than calories per se or particular food groups accounted for the increases in BMI. These empirically based theories and data suggest that one should focus on palatability and addictive models in dealing with the increasing problem of obesity in the United States.