From gym memberships to free Fitbits, companies are offering an array of incentives to encourage their employees to get healthy and lose weight. It’s an admirable goal with a financial bottom line: Workforce wellness translates into fewer absences and reduced health insurance costs for the employer. Mitesh Patel, a professor at the Perelman School of Medicine and a professor of health care management at Wharton, thinks there’s a better way to motivate employees than with freebies. His most recent research reveals that cash lotteries are powerful incentives for people to lose weight. The paper he coauthored on the topic is titled, “ A Randomized, Controlled Trial of Lottery-based Financial Incentives to Increase Physical Activity Among Overweight and Obese Adults .” Patel, who is director of the Penn Medicine Nudge Unit , the world’s first behavioral design team embedded within a health system, recently spoke about his team’s findings on the Knowledge at Wharton radio show on SiriusXM .…