In this *Very Short Introduction* , David Bender explains the basic elements of food, the balance between energy intake and exercise, the problems of over- and under-nutrition, and raises questions on the safety of nutritional supplements. Looking broadly at what constitutes nutrition, Bender provides insight into a topic of wide interest and importance in today’s world. With a look at diet in relation to nutrition, this *Very Short Introduction* provides an overview of the biochemistry of nutrition and the health risks associated with poor nutrition- including obesity and types of food allergies. It provides an essential guide to effectively understand the principles of, and necessary reasons for, a healthy diet. **ABOUT THE SERIES:** The *Very Short Introductions* series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.