I've never felt lactose "intolerant", as in, I can eat some and be OK. Ice cream, cheese, etc has never been a problem. But occasionally too much can make me a bit gassy. It tends to be milk/cream products. I notice after my morning coffee with cream a bit of gas.
I currently run 5/3/1. For weight loss, I've had good success in the past with high protein/moderate carbs/low fat. Hence what I'm doing now. I do have the CBL book, I've been reading it, but I haven't digested it all (no pun intended). It is compelling, though, and I may consider it soon. However, I also am a believer that when it comes to diet, compliance is king. I've done low carb before and it's a nightmare. Feel like shit, shitty breath, low energy, and worst of all, weak in the gym. Perhaps it's a mental barrier, but if I'm always going to feel like that doing low carb, it's not worth it.
I think I'll lower the protein and up the fats a bit for now, and see how that goes. That's always the pain in the ass with GI issues.. a lot of trial and error is needed.
I highly doubt it's the carbs in my case. The days I tend to feel best are Sundays, which for me is a bit of a cheat day, which for me means no protein powder, smaller protein intake in general, and more carbs and fat.