With the peptides that are being used to cause or enhance a natural pulse (GHRH' and GHRP's) it is advised to be in a fasted state otherwise you will blunt the release to some degree. From my own experience and research the pulse peaks around 10 mins after dosing. Using those for a general release if youre going to eat the suggestion is to wait at least 20 mins (to 30 for me). If prioritizing fat loss the peak of the lipolyzing effect is at about 90 minutes so the suggestion there would be stay fasted and be about a 3rd of the way through cardio session at 90 minutes.
The blunting is all about the hormonal interactions around blood sugar, insulin etc and even fats. Theoretically pure protein shouldn't matter but why risk it when fatloss is the goal.
Fair warning, I know from personal experience that these timings are effective and proven for many people but their may be more recent research that would suggest different and possibly more effective timing than I have. I always welcome new info if available.
Other things that have been discussed as bunting include opiates and MJ but research I've seen is fuzzy, I wouldn't chance it though.
With exo GH you are the pulsing mechanism.