Unit 15
What Is the Healthiest Diet?

The great 17th-century physician, Boerhaave, kept an elaborately bound volume that was said to contain all the secrets of medicine. When it was opened after his death, all the pages were found to be blank, except one. Inscribed on this page was but one sentence:

“Keep the head cool, the feet warm and the bowels open.”

Here we review what we have learned in the course and summarize the quantities of the “healthiest” diet. It should be clear from the preceding units that chronic diseases are associated with a diet high in fat (particularly saturated fat) and sodium, and low in dietary fibre.

The rational approach to the question of chronic diseases is primary prevention based on a healthy lifestyle, particularly good nutrition. The evidence we have presented reveals that essentially the same diet prevents virtually all of the major chronic diseases. Furthermore, the evidence leads us to conclude that some of the chronic diseases are potentially reversible, and that diet can make a major contribution towards this reversal. However, the appropriate diet for disease reversal is stricter than that for primary prevention.

Objectives

After completing this unit, you should be able to

1. describe the key features of a diet that offers maximal protection against chronic diseases of lifestyle.
2. discuss the role of non-dietary lifestyle choices in causing or reducing risk of chronic diseases.
3. identify the benefits of a population approach to healthy eating vs. a high risk approach.
4. discuss how diets can be adapted to reduce harmful effects on the environment.