I'm fairly paleo (80%) and am also fairly lactose intolerant. I pop a digestive enzyme with lactase when I do eat softer cheese or other dairy. Yogurt, butter, kefir, fermented dairy, hard/aged cheese in general doesn't bother me. Cow's milk is like death.
So, naturally, for an indulgence, I chose some Jeni's ice cream (a gourmet shop in Ohio) and realized I had run out of lactase. "Oh well," thought I..."it can't be that bad."
It was like GI agony - like someone pumped up my colon with air and then was stomping on my guts. Awesome!
That was Sunday. For the last few days, it seems like everything I put in my mouth is causing mild GI cramping. Steak and broccoli was awful. So I scaled it back to homemade chicken bone broth with veg and chicken. Not so hot. This morning I had two eggs with a little pat of pasture butter. I feel ok, but my guts are still a bit rumbly.
Anyone had this happen after a non-paleo indulgence that caused GI distress? I've never had something linger like this.
Yeah, the [insert bad food] works its way through your system in 1-3 days but it can take 1-3 weeks for your gut to heal. Or even more.
If you had a nasty rash break out on your skin, it's unlikely you'd see it clear completely in a day or two and if you imagine your gut as highly specialized skin, even after the ice cream went past the tissues probably looked pretty sore and angry.
I've definitely found that if my reaction is mild I'm fine in about a week. If I have a bad reaction, such as from wheat, it's more like a month or two.
Not only what Nance said, but there still could be trace "fermentables" in your gut, I've had dairy issues (usually from a one-two punch combination of good beer and copious amounts of cheese) that have lasted for over a week... bloating, gas, very poor/slow "evacuation" (i.e. mudbutt), etc...
The best resolution I've found is to simply not eat for a day or so, then have a meat-only / vlc day, followed by resuming your standard way of eating (except adding some Kombucha if you can get it).