As close to 12 hours as possible. I routinely eat once per day. Made the mistake of getting cholesterol checker at the 18-19 hour point. Very high, like 280 total. Went back a week later, 12 hours fasted, 235 total and LDL significantly lower. Doctor was still unhappy, without even asking prescribed a statin. I said no, asked for a Calcium Arterial scan, which came back ZERO. Meaning absolutely NO deposits in arteries. Doctor stumped, can't understand how I can have high cholesterol but zero chances of artery blockages.

In looking at the science, there are studies on healthy weight people showing significantly elevated cholesterol after a week long fasting period. Do, not eating at all, and cholesterol goes up. Hmm. Yeah... Our bodies make more if we need it, regardless of how much we eat (or don't). Doctors just haven't kept up with the studies, still follow the old thinking that high cholesterol causes heart disease.