Diaz co-authored 'The Body Book: The Law of Hunger, the Science of Strength, and How to Love Your Amazing Body', a health and wellness guide focused on nutrition and exercise. The book became a New York Times bestseller.

Diaz co-authored 'The Longevity Book: The Science of Aging, the Biology of Strength, and the Privilege of Time', a follow-up to 'The Body Book' that focused on the science of aging and the importance of healthy living throughout life.

Diaz co-founded Avaline, an organic wine brand, with entrepreneur Katherine Power. The brand focuses on producing vegan-friendly wines with transparent ingredient labeling. Avaline quickly gained popularity, reflecting Diaz's interest in health and wellness.