Nothing ‘sits’ in your gut. Your digestive system is not a recycling centre that carefully separates your food into meat, vegetables, grains and so on and then processes them separately. You chew incoming food into a rough mash; it moves into the stomach for another round of mixing, mashing and marinating, and then travels through the intestine as a fairly homogenous paste.
It’s not a constant speed conveyor belt – the muscles of the intestines can move food forwards and backwards in order to extract all the nutrients and the rate of travel depends on how much indigestible fibre and water there is. But it’s important to realise that meat, vegetables and chewing gum all move – and exit – together.
The widely held myth that meat hangs around longer than other foodstuffs probably stems from the fact a high-protein diet results in a lot of leftover ammonia, which must be removed in the form of urea by the kidneys. This uses extra water and if you don’t drink more to compensate, the dehydrating effect can result in constipation. But in a normal, omnivorous diet, the meat will complete its journey through your digestive system in 12 to 48 hours, along with everything else.