igf-1 levels increase synergistically with insulin, so eating carbs will increase your igf-1 levels, yeah. though, these are your systemic igf-1 levels, which don't play a role in muscle accretion but rather for body growth (i.e. children growing, and also adults getting enlarged noses, hands, heads, etc...)
so no, not a waste. it will probably work better for reshaping your physique as insulin stops lipolysis - which is the way that hgh causes fat loss.