Dr. T. Colin Campbell, renowned author and advocate for a plant-based diet, will be a guest on HBO’s Real Time With Bill Maher tonight. Campbell is best known for his best-selling book The China Study, which examines the negative impacts of consuming dairy and meat products and details a comprehensive nutritional study he conducted in China alongside Cornell and Oxford Universities. Fans of his work include Bill Clinton, who adopted the plant-based diet recommended by the book. Campbell is also a subject of the recent documentary Forks Over Knives, which depicts his life and career alongside the filmmaker’s step-by-step conversion to veganism. Campbell will discuss the film on Real Time at 10pm tonight.