I've been on Metformin for quite a number of years. I did quite well for a number of years with diet and exercise alone but now my body can't cope without Metformin. I still need to work hard at it. For a while I had free access to a gym and got into (light) weight training. Would you believe my body coped better with everything?but when you take it, are you able to eat at least a few more carbs than if you weren't taking it? If he could just eat a few more carbs without having his bgs hit 140, I think he would keep the carbs down to a dull roar. Otherwise I'm afraid he will give up altogether.