"We stop them, but they get to keep the money they stole from consumers by fraud," he said.
In some cases, a company relents to pressure from consumer groups but is sued again by private interests seeking a cash payout to people who bought the product.
Such was the case with Ben and Jerry's ice cream, which took the claim off 48 products in 2010 but has since faced a drawn out class-action lawsuit.
Some companies have quietly dropped "natural" from their packages, including Naked Juice and Frito Lay chips, as the food industry faces thorny legal questions over genetically modified ingredients and common additives like corn syrup.
In Gardner's view, the lawsuits would stop if the FDA came up with a definition for "natural."
But Baylen Linnekin, executive director of the non-profit group Keep Food Legal, said more regulation is not the answer.
"The idea that the FDA needs to define every word that has ever been used to refer to food is ludicrous," said Linnekin.
"The occasional lawsuit helps keep companies honest and that has always been the case."