U.S. obesity as delayed effect of excess sugar.

•While many population health studies have invoked sugar as a major causal factor in the obesity epidemic, few have explicitly explored the temporal delay between increased sugar consumption and rising obesity rates.•We model the increase of U.S. adult obesity since the 1990s as a legacy of increased consumption of excess sugars among children of the 1970s and 1980s.•The model captures the generational time lag through a stochastic process of superfluous sugar calories increasing obesity rates over the lifespan of each birthyear cohort.•Driven by annual USDA sugar consumption figures, the two-parameter model replicates three aspects of the data: Delayed timing and magnitude of the national rise in obesity since 1970.•Profile of obesity rates by age group for a recent year.•Change in obesity rates by age group among pre-adults.•Our results indicate that past U.S. sugar consumption is at least sufficient to explain adult obesity change in the past 30 years.