Thanks for writing more on this matter. The ‘heaviness’ of meat that you describe is not really because it’s difficult to digest. Lentils and white beans are more heavy to digest, and even cauliflower, as I know for my late dinner yesterday with grilled cauliflower which I love: but not recommended to eat before going to sleep.
The problem of meat is twofold: the adrenalin, and the antibiotics. I do not talk about meat from a farmer where you know they do organic farming and respect the animals which are fed naturally. Then there is less of a problem. But we are living in a meat industry culture which is a totally different story.
Please read the revelatory books of Michael Pollan:
In Cooked, Michael Pollan explores the previously uncharted territory of his own kitchen. Here, he discovers the…michaelpollan.com
But even meat from a farmer contains a high dose of adrenalin for no animals wants to be killed and is in great stress during the process of being killed. I for myself have decided to not eat meat for this reason among others: I do not want animals to be killed. We do not need to eat meat after all, and research has shown that our intestinal tract is as large in proportion to vegetarian animals like gorillas or elephants. Meat eaters among animals like Tigers or Lions have very short intestinal tracts and thus the meat doesn’t rot inside for long (which is one of the causes of colon cancer in most Western cultures).
What you actually feel as ‘heaviness’ — and I know very well what you mean for in my twenties I was pretty much unconscious of all of that and was eating meat like everybody else, and then after dinner could not follow university classes or seminars for I was so terribly DIZZY. This dizziness is from nothing else than the terrible adrenalin injection you got by eating your steak, much like you would smoke a huge heavy cigar just before going to sleep: the nikotin injection would keep you awake for long …