Pro Tip: If you can't eat enough while/after binging on stims, drink tons of milk.

A 4 pint bottle of full-fat milk is almost 1500 calories. There are nearly 1000 calories in 4 pints of fat-free milk too if you prefer that. Remember milk is evolved to turn calves into 1500lb cows, it can give you all you need to build muscle too. Creatine etc. is unnecessary.

Milk is a close enough approximation to the nutrition we need that you can easily substitute most of your food for at least a day or two with milk. Much easier to get your 2000-2500 daily calories down if you take 75% of them in the form of a smooth lubricant liquid...

Also, if the reason you can't eat is because your mouth is too sore from bruxism, but you are still hungry, a pint of milk will make you feel full for 2-3 hours, pretty much the only liquid that can do that, plus this means that if you drink milk as your only liquid it's virtually impossible to drink too much and cause water toxicity (this is what happens to people who try it).