well if you talking about a commercial weight gainer the best with lowest sugar would be Metrx gainer. Its best to split the servings in to 2, and take them at different times during the day. I think a serving is 52g pro, 150g carbs (only 7g are sugars), 3.5g fat or something like that and then I split it up into to meals and add an extra scopp of Protein to each serving. Otherwise if you r looking for something thats a little lower in calories go for a MRP which is a slow digesting protein like egg or casein protein and some carbs. Or you also can just make your own weight gainer with some protein, ground oatmeal (grind in coffee grinder), flax or NPB, maybe a banana or other fruit, or cottage cheese.