Try splitting your dose if possible so you take it twice a day with meals as already suggested, and see if that helps. And try going easy on carbohydrates, as they can have diisagreements with metfartin in your gut, and start to ferment and any resulting gas obviously needs some means of escape. I can get quite windy occasionally now if I eat too much starchy carby food, but most of the time I don't have any problems.
Charming subject isn't it!
Robbity
PS If all else fails ask your pharmacist if you can try a different brand - one I was given made me very nauseous.