What happens when you cheat on the paleo diet? I'm talking pizza, ice cream, chinese food, etc. I'd like to know because I want to make this my lifestyle-meaning sometimes I'm going to go out and enjoy food just for the taste. I know I might end up feeling sick, but I want to know what will happen in terms of weight and body composition. The paleo diet seems to be more about insulin and stuff, not so much about calories...so I'm afraid I'll gain weight if I cheat because it will mess up my insulin levels or something. I've been reading the forums and it sounds like people can gain weight from just a couple slices of bread? Kinda scary...

After two years now, I've realized that I need to stay on a LC version of the paleo diet. If I don't:

I put on water weight. Immediately. My joints begin to ache. My mental processes - memory, cognition, etc. - slow. My sleep becomes troubled. I become sedentary. I become quick to anger. I begin to crave carbs; and if I succumb, all my symptoms grow even worse.

The list goes on. Of course you might be more tolerant of variations in your diet than I am.

God kills a kitten

It kind of depends how often you do it. As your diet changes your intestinal flora also changes. Bacteria that help you digest grain die off if you don't eat any and ditto legumes. So if you drop that stuff back in you might have some unpleasant side effects. However, the first paleo diet book I read said that you could still get most of the benefits by eating clean on weekdays and anything on the weekends. i would guess that might keep your gut flora varied enough. I tried that but in the end for me I think it's best to be as clean as I can all the time. (coffee and chocolate in small quantities excepted of course)

For me it depends on the cheat. Grains other than white rice lead to diarrhoea, not something one is tempted to do too often. I imagine dried legumes would do the same but I haven't tried it. Fresh legumes (eg snow peas, green beans) seem to be fine, so eat them as an occasional vegetable. Tubers don't seem to have any noticeable ill effect, so I'm not so strict about them - I eat them as an occasional vegetable, I just monitor my intake, and if my weight starts to track up again I'd cut them completely. Dairy other than butter makes me a bit gassy as I have lactose intolerance, but I eat some as treats. Again, dairy would go completely if my weight was tracking up. Sugar makes me feel peculiar, and I don't enjoy the taste much any more, so I have very little. Bad fats don't have a noticeable effect, I'm just aware of how much damage they're doing my body, so I avoid them wherever practicable.

I'm not terribly strict. I enjoy my food, and there are some non-paleo foods I don't want to live the rest of my life without, such as good cheeses. But I don't make those foods everyday foods - I reserve them for treats, and I keep in mind that they're not good for me - I don't try to invent reasons why they're "OK, really."  When I cheat, I try to get maximum enjoyment for it. eg I wouldn't bother eating cheap chocolate - if I'm going to feed my body something that is bad for it, it has to divine-delectable to make it worth it. I went out for a day in Melbourne with DH on Friday. It was a warm day and we did a lot of walking. Towards the end of the day I had an iced coffee! OMG it was delicious. It was real coffee with milk and good-quality ice-cream and no other added sugar. If they did that ghastly coffee-flavoured syrup I wouldn't have bothered. I didn't feel bad about it, I felt like it was a very special end to a special day.

I would imagine if anybody gains pounds from eating a couple of slices of bread they must have been low-carb and that weight will be water. It'll go as soon as they get back to low carb.

I'm afraid I'll gain weight if I cheat because it will mess up my insulin levels or something. I've been reading the forums and it sounds like people can gain weight from just a couple slices of bread? Kinda scary...

Yes, that's been seen repeatedly.  It does seem to be mostly water and glycogen weight, but that weight still takes at least a little time to get rid of again.

There was one man who managed to lose weight in the long term doing the "paleo during the week" thing, gaining a few pounds each weekend but losing a bit more each week.  He isn't around any more, though, so the constant nonpaleo food may eventually have gotten him to quit paleo entirely.  The technique doesn't seem to work at all for women, who don't seem to be able to lose enough during the week to make up for weekends of carby cheats - in general, losing weight is more difficult for women.