Fat Breakdown:

GH and insulin control the level and activity of hormone dependent
lipases. More GH and less insulin will break down fat, sending the free
fatty acids and glycerin to the liver to support ketone production and
gluconeogenesis respectively. One only needs enough GH to release the
fat that the liver needs. Too much would only increase blood viscosity
and encourage clotting activity (as happens after a fatty meal). That's
why the negative feedback loop exists.

Breakdown is subject to limits of circulatory clearance. Intra-abdominal
fat is well supplied with blood flow and can store or release several
thousand calories of fat per day. Sub-cutaneous body fat is probably
limited to storing or releasing about a thousand regardless of the
circulating GH level. Muscles can store thousands per day but as with
glycogen they retain it for their own local use and do not release
either back to the shared circulation.

If the body is preadapted to ketosis (and thus metabolizes released fat
quickly) and has already drawn down intra-abdominal fat inventory, it
may well secrete monumental levels of GH to push the circulatory limit
of fat release from subcutaneous stores.

A body with large inventory of intra-abdominal fat would require only a
low level of GH, probably not more than 2:1.

Protein Breakdown:

A body pre-adapted to carbohydrate metabolism would primarily release
cortisol and degrade muscle to free amino acids for gluconeogenesis. GH
would impede this process and would probably be REDUCED during the fast.