His grocery chain already offers health care to workers at the 30-hour threshold. But he said the company may be forced to reconsider its full-time staffing levels, if the final employer mandate rules still being crafted by the Obama administration require companies to offer costly benefit options.
"Say we're paying $3,200 a year for insurance for somebody, and the new regulations cost us $5,000 to insure somebody. If they work fewer hours, we just saved $5,000 per person," because there is no mandate to provide coverage for part-time workers, he explained.
(Read More: John Mackey: Obamacare Likely to Raise Costs)
Darden Restaurants, with 45-thousand workers, experimented with cutting back on full-time staffing at some of its restaurants last fall. After a public backlash, the chain said it would not change its staffing in 2014.
"We have always had a significant number of full-time employees and they are integral to our success," said Darden Chairman and CEO Clarence Otis in December. "The data we have collected during our test around guest satisfaction and employee engagement has only reinforced this."
RULES STILL NOT SET
"There's going to be a lot of complexity," said Neil Trautwein, Employee Benefits Policy Counsel at the National Retail Federation (NRF).
The Obama administration is expected to finalize the new rules by spring. So far, Trautwein and others have said officials have been responsive to business concerns about the details.
"We've made some progress on the question of variable workers," he said. It's likely the final rules will include a one-year look back period of an employee's weekly hours to determine full-time status, so that the mandate isn't triggered for seasonal workers. (Read More: Obamacare Is Here to Stay. Now What?)