It can be a number of things: food intolerance, low stomach acid, low digestive enzymes, lack of CHEWING, etc... but if you're eating GRAINS AT DINNER, you're missing the boat entirely. DROP THE GRAINS. Give it 2-8 weeks and get back to us. Grains are not food and they're not paleo. Really.
I think the first thing one should cut out when going Paleo is grains. There are lots of things that can cause gas, but grains would top my list, especially with bloating involved as well. Try cutting them out for at least 2-3 weeks straight - no cheats - and see what happens.
That mention of "dessert" is also ominous. Dessert could have any number of bad things in it: grains and sugar, for one. But there's also the possibility of chocolate? Lots of paleos love dark chocolate, of course, and I sometimes eat 90% or 100% cacao. But in my own self-experimentation I've determined that it can in fact lead to some bad smells on the other end, so to speak.
Its grains.. grains.. grains. I quit grains completely after 50 years of grain intensive diet with daily rampant flatulence. Now, only after 6 months of paleo, free of gas, even a small amount of grain causes me to explode. I could be a special case, but anecdotal evidence points to this over a wide range of population
I don't eat any grains and still get gas. I finally worked out it might be from drinking some of my homemade probiotics (water kefir and kombucha) or fermented vegetables which have not fully fermented yet- eg they still have some sugar in, which the bacteria in your gut devour and then excrete gases. I should add though that if done properly (e.g. fully fermented) such probiotics should decrease flatulence, not increase it! (so it might be an idea...)
The foul-smelling stuff is often a product of bad bacteria in the small intestine that feed on refined sugar and grain sugars. Eliminating grain products and sugar will eliminate foul-smelling gas. That is my working hypothesis and in my n=1 studies, this has been proven conclusively. (Insert smiley face.)
Some vegetables will lead to gas, and milk products as well. But the poisonous, really awful stuff (plus bloating and so on) really says "grain" to me. Incidentally, even the smallest quantity will do it. A bit of starch is a ton of food for bacterial populations in the gut.
Thanks for the replies guys,I think the ultimate culprit is definitely grains. When I say I eat grains and dessert these are a rare occurrence,I follow the 80/20 rule!I always find my stomach is bloated and gassy around lunch time after eating something unpaleo. I'm going to if tomorrow till dinner to see if there is any improvement.
I've been taking inulin and magnesium before bed too but still feel 'packed up'!I'll see if that improves too!