It's just your body adjusting to the new food regime and will improve. Some suggestion on managing it would be to make sure you take your time eating and chew your food properly (if you gulp your food you ingest more air), drink loads of water and try some peppermint tea which is great for the digestion.
I did suffer a lot and found it was caused by hi-fi bars and oats. Well, any Hexb that is cereal based.
I loved hi-fi bars, alpens and the "magic porridge" but if I had those I would really be windy all day which was awful being at work! I found it was those as I seldom ate them over the weekend and was wind free. Back at work with any of the above and the wind started. I have stopped them plus have 2 Activia Lights every day and I am now almost totally wind free and am as regular as clock work, which I never was.
If I eat alpen light bas I get terrible trapped wind. Never had it before, has me doubled up the pain went right up my back. A friend, a very good friend as it turns out, at work told me I need to pass that wind I went for a quick walk outside....and without being a bit crass I have never farted like that in my life. I swear it was ridiculous the noises I was making, thankfully nobody near to hear so embarrassing. Instant relief though. I now steer clear of the alpens!!!