I've read that before, but I guess what strikes me as odd is how it wasn't until I hit my 30s that I suddenly started shitting my brains out whenever I consumed more than a small glass of milk. I drank a lot of milk growing up...it was pretty much that or water much of the time, and even after I went off to college and stuff I still went through a gallon by myself every 3 or 4 days. Not even just milk but WHOLE milk...I didn't switch to skim until my 20s when I moved in with my gf and she hated whole milk.

Anyways, after three decades of no issues whatsoever, and zero change in my habits, suddenly my body decided "NYET! NO MORE!!!" and my ability to properly digest lactose evaporated basically overnight. I didn't even make the connection until I was traveling and wasn't drinking any milk on my trip and didn't have any problems, but then got nearly crippled the next morning after I had a big ol bowl of Captain Crunch before bed the night I got home.

There's no way our bodies are "supposed" to be. There's the way they are and the way they were. Also some brave and dedicated individuals can apparently overcome lactose intolerance through exposure therapy. Basically they eat a bunch of dairy every day for weeks until their gut biome readjusts to digest lactose without all the discomfort. Apparently the gas and bloating are caused by the overgrowth of some bacteria and it just takes some time to find a new equilibrium so you don't get big blooms every time you eat lactose.