The key there is the "L" in that LBM...If the weight you are gaining is lean body tissue and not adipose tissue,you have very little to worry about.Unfortunately it is very rare not to accumulate some of the latter when you are adding the lbs on...Best option is to cut up on a regular basis and try to be as lean as possible when diving into a bulking phase,and watch your intake of saturated fats/cholesterol year round.Incorporating the omega Fatty acids into the diet also goes a long way toward maintaining a healthy cardio vascular system.