Intermittent Fasting Knowledge Center

Fasting as a Young Adult: Building a Lifelong Health Habit

Why starting fasting in your 20s or 30s builds a foundation for life, drawing on Upton Sinclair's 1911 account and modern research on habit formation.

Read answer →

Why the Sick Often Fast More Successfully Than the Healthy

Upton Sinclair's 1911 book The Fasting Cure argued the weaker and sicker you are, the more you need to fast. Here's the historical case and what modern science says.

Read answer →

Fasting in Your 60s and 70s: Is It Safe and What Should You Expect

Fasting after 60 raises different questions than fasting at 30. Learn what a 1911 case study and modern research say about safety, muscle loss, and results.

Read answer →

Can Older Adults Fast? Evidence from Cases in Their 70s

Historical cases from 1911 and modern research both address whether fasting is safe for older adults, including a documented case of a couple in their 70s.

Read answer →