The contribution of expanding portion sizes to the US obesity epidemic.

OBJECTIVES Because larger food portions could be contributing to the increasing prevalence of overweight and obesity, this study was designed to weigh samples of marketplace foods, identify historical changes in the sizes of those foods, and compare current portions with federal standards. METHODS We obtained information about current portions from manufacturers or from direct weighing; we obtained information about past portions from manufacturers or contemporary publications. RESULTS Marketplace food portions have increased in size and now exceed federal standards. Portion sizes began to grow in the 1970s, rose sharply in the 1980s, and have continued in parallel with increasing body weights. CONCLUSIONS Because energy content increases with portion size, educational and other public health efforts to address obesity should focus on the need for people to consume smaller portions.