I'm 5'6" and weight ~127lbs and can bench press about 245 lbs and I maxed out with 100lb dumbbell presses today. I've been working out for about 7-8 years but my weight has always been under 130lbs. I've even tried weight gainers and protein shakes but I have to watch how much carbs/sugar I intake because I have family history of diabetes and can't consume too much carbs/sugar or my blood glucose will get too high. I do eat as much or even more than my workout partner who weights 200lbs. Why is it so hard for me to gain weight? How do I gain mass/weight with my condition?