What is the fine-grained topic of the following text: The Diet Delusion is an in-depth, scientific, groundbreaking examination of what actually happens in your body as a result of what you eat, rather than what the diet industry might have you believe happens and is essential reading for anyone trying to decide which diet – low-fat or low-carbohydrate – is truly the healthy diet. Only return the topic.
Analysis of the book "The Diet Delusion" and its impact on diet choices.