Six small meals a day at intervals of 3 hours is the answer.
Two simple facts of physiology will explain why: (1) It takes about three hours to digest each meal, and
(2) protein (amino acids) lasts
about three hours in the bloodstream.
Also frequent meals keeps the metabolism regulated. This works with 5 meals as well.
If you sleep eight hours per night, that leaves 16
waking hours in the day. Six meals over 16 hours equals one meal every 2.7 hours. If your goal is five meals, then your target is one meal every 3.2 hours. Average it up for simplicity, and that’s where the guideline of one meal every three hours comes from.