Food availability of glucose and fat, but not fructose, increased in the US between 1970 and 2009: analysis of the USDA food availability data system

BACKGROUND: Obesity rates in the United States have risen consistently over the last four decades, increasing from about 13% of the population in 1970 to more than 34% in 2009. Dietary fructose has been blamed as a possible contributor to the obesity increase, although the consumption pattern of fructose and other key nutrients during this 40 year period remains a topic of debate. Therefore, we analyzed the USDA Loss-Adjusted Food Availability Database in combination with the USDA Nutrient Database for Standard Reference (Release 24) to determine whether fructose consumption in the US has increased sufficiently to be a casual factor in the rise in obesity prevalence. METHODS: Per capita loss-adjusted food availability data for 132 individual food items were compiled and analyzed. Nutrient profiles for each of these foods were used to determine the availability of energy as well as macronutrients and monosaccharides during the years 1970-2009. The percent change in energy from food groups and individual nutrients was determined by using the year 1970 as the baseline and area-under-the-curve analysis of food trends. RESULTS: Our findings indicate that during this 40 year period the percent change in total energy availability increased 10.7%, but that the net change in total fructose availability was 0%. Energy available from total glucose (from all digestible food sources) increased 13.0%. Furthermore, glucose availability was more than 3-times greater than fructose. Energy available from protein, carbohydrate and fat increased 4.7%, 9.8% and 14.6%, respectively. CONCLUSIONS: These data suggest that total fructose availability in the US did not increase between 1970 and 2009 and, thus, was unlikely to have been a unique causal factor in the increased obesity prevalence. We conclude that increased total energy intake, due to increased availability of foods providing glucose (primarily as starch in grains) and fat, to be a significant contributor to increased obesity in the US.