Leslie Knipfing is an American author who is Kevin james sister, speaker, and advocate for the low-carb lifestyle. She has written several best-selling books, including "The Ketogenic Cookbook" and "The Low-Carb Gourmet Cookbook." Knipfing's net worth is estimated to be around $2 million. Her success in the low-carb industry is mainly due to her popular blog, "Low-Carb Yum," which she started in 2004.