Fasting is the best way to maintain health. A Harvard doctor locked three obese men in a hospital and didn't give them any food for 40 days.

Their mental clarity was better than ever before.
Dr. George Cahill. Harvard Medical School. Peter Bent Brigham Hospital. 1967. He had a question in the medical community that was considered settled.
What if the brain doesn't actually need glucose?
The orthodox medical view is unquestionable. The brain consumes 120 grams of glucose daily. Without food, brain function would collapse. These men were expected to become mentally ill within two weeks.
Day 7. Mental fog. Hunger. Irritability.
Day 14. Symptoms subside. Hunger disappears. Energy is restored.
Day 21. Day 28. Day 40. Sharper than before the start.
Cahill measured their blood. The brain no longer relies on glucose to operate. It begins to rely on ketones. A fuel produced from body fat.
The brain switched fuels. Effortless.
These men lost dozens of pounds. Mental clarity improved. Insulin levels plummeted. Ketones provided their energy. Cahill published the results in the Journal of Clinical Investigation.
And then the medical community quietly buried it.
They tell you the brain runs on sugar. Harvard proved 59 years ago that this is not true.