While the report, published recently, suggests that a disproportionate amount of food stamp money is going toward unhealthful foods, the U.S.D.A. said it was unfair to single out food stamp recipients for their soft drink consumption.

The report compared SNAP households and non-SNAP households. While those who used food stamps bought slightly more junk food and fewer vegetables, both SNAP and non-SNAP households bought ample amounts of sweetened drinks, candy, ice cream and potato chips. Among non-SNAP households, for example, soft drinks ranked second on the list of food purchases, behind milk.

“Sweetened beverages are a common purchase in all households across America,” Kevin Concannon, the U.S.D.A. under secretary for food, nutrition and consumer services, said in an interview. “This report raises a question for all households: Are we consuming too many sweetened beverages, period?”

The report was based on data from an unnamed, nationwide grocery chain, which provided the U.S.D.A. with monthly records of food items bought in 2011 by more than 26 million households, about three million of them food stamp recipients. The grocery chain identified and tracked SNAP households by their use of SNAP benefit cards at the checkout aisle. One limitation of the report was that it could not always distinguish when SNAP households used their benefits, other money or a combination of the two to pay for transactions.

Nonetheless, the report provides a striking look at the foods American households typically buy.

Across all households, the report found, “more money was spent on soft drinks than any other item” — a finding that reflects the fact that, while consumption of sugary drinks is lower today than it was a decade ago, the United States still consumes more sugary drinks than almost any other developed country, studies show.