Whole Foods Staffers to Pay Less If They Weigh Less

"Staffers whose health is ranked "platinum" will benefit from a 30 percent discount, while those in the bronze range will get 22 percent. That's a difference of $4 on a $50 grocery purchase. Staff members who opt out of the in-store health screenings still get the usual 20 percent employee discount."

http://www.aolnews.com/nation/article/whole-foods-staffers-to-pay-less-if-they-weigh-less/19331110

How would a behaviorist describe what Whole Foods is doing here? What might they consider doing to imporve their successes?