"In Defense of Food" is a book by Michael Pollan that critiques the modern food industry and its impact on health. Pollan argues that the rise of processed foods and nutritional science has led to confusion about what constitutes healthy eating. He emphasizes the importance of returning to whole, natural foods and traditional eating practices. The book promotes a simple mantra: "Eat food, not much, mostly plants." Pollan encourages readers to focus on the quality of their food rather than obsessing over calories or nutrients. By doing so, he believes individuals can improve their health and reconnect with the joy of eating.