for fish oil quality is important. i don't think GNC would be my choice. go with something like life extension super EPA/DHA. more expensive but worth it IMHO
Granted fish oil is fat, which means extra calories....but it's "good fat", just like flax / olive oils... I always thought good fats don't significantly contribute to fat-gain... if anything, they help prevent it?
First off its excessive calories like mac said, secondly you are probably taking these with meals that contain carbs so your are getting your insulin levels up then adding 10 g of fat at each meal. If you are carb sensitive like meal you should avoid eating any fat with carb meals like the plague.