From first hand experience.. thats a myth.. my stomach is tight as hell right now after a butt ton of insulin, gh, igf, etc. gut distension comes and goes from food allergies, swelling, intestinal swelling from leaky gut from the food, and the associated side effects from excess food like reflux, acid erosion, liver swelling from tren and orals pressing on the stomach causing distension, etc.
Its better in the offseason and gets severely and drastically worse closer to stepping on stage. There is nothing you can do about.. the intestinal lining swelling, especially from stress, the stress on the body from drugs, diuretics, excess cardio, training, etc. The body diverts blood to the vital organs, heart and brain, placing even more stress on the guy, leading to swelling of the stomach and intestines..
BOOM, swollen pregnant belly... I hate this freakin myth. The bigger you are, the bigger your intestines, the bigger your gut will be. Thats why the pros get called out for this. lightweights 150lbs backstage look 9 months pregnant letting it out.