An Illinois man begins a 15-month jail sentence on Tuesday - for misleading dieters into buying doughnuts.
Telling porkies: Doughnut salesman said they contained only 3g fat
Robert Ligon, 68, repackaged normal doughnuts as "low-fat", saying they contained only three grams of fat and 135 calories, and were "carob-coated".
In fact, they contained 18g fat and 530 calories, and were chocolate-glazed.
Ligon was caught when suspicious customers complained to the Food and Drug Administration about how tasty his products were.
"If it sounds too good to be true, it probably is," Jim Dahl, assistant director of the FDA's Office of Criminal Investigation, told the Wall Street Journal newspaper.
"Science can do a lot of things, but we're not quite there yet," he said.
Ligon's conviction follows a three-year investigation during which his premises were raided and 18,720 doughnuts seized.
Officers found that for two years he had been turning a healthy profit, buying the doughnuts for about 25 cents each and selling them for $1.
But Ligon's lawyer, Rick Halprin, said he was shocked at the custodial sentence.
"I've had people go to jail before, but never over doughnuts," he said.
He complained prosecutors had failed to prove the mislabelling had harmed anyone.
"They didn't bring in 10,000 overweight people," he said.
Ligon himself says he did not break the law intentionally and has never received a single complaint.