Muscle conservation in long fasts vs. short ones.

One of the aspects i don't love about repeated short fasts such as 3 days is that the early transition from carb metabolism to fat metabolism (ketosis) is expensive in the muscle or other protein tissue required and this generally takes place somewhere within the 30-60 hour window. Once our body runs out of stored carbs (glucose and glycogen), the body begins the transition into burning fat as the primary fuel source and in this interim period the body converts a fair amount of protein to glucose to keep the body provided with what it needs.

If a person had a big tumor this could actually be an exceedingly good thing... and if i had such a tumor, then multiple 3 day fasts would actually be my strategy in eliminating it... but generally speaking we don't want to burn that much protein repeatedly, so one great benefit of a long fast as opposed to many short ones is that once you pay that transitional price in protein tissue the remainder of the fast is extraordinarily muscle preserving by comparison. Over a single 30 day fast, we would burn about 2.5 times less protein tissue than we would over ten 3-day fasts.