Does dropping gluten help you loose weight?
I would ask, how long have you been training for? Are you relatively new to the sport or are you a seasoned performer.
If you've been around a while it might be that your body is adjusted to where it needs/wants to be based on the stresses you put it through. Do you mix up your training, e.g. include HIIT sessions to boost metabolism, if you focus too much on low and slow then some studies will show that your basal metabolism will adjust accordingly, i.e. it'll burn less as well, so try and keep things mixed up.
Another idea which can help promote fat metabolism but limit chronic loss of muscle is nutrient timing and doing fasted session. I will often try to do a circa 60 minute run of 80 minute easy fasted ride (before breakfast) in order to promote metabolism and then get your food in afterwards. This means your body promotes fat burning during your easy ride (very good) and then is fuelled to recover and rebuild strength afterwards (also good). Conversely, if you find you don't eat much during the day and fill up at dinner time you are giving your body lots of energy and nothing to use it for apart from stock up on fat, which isn't what you're looking for.
I'd be wary of cutting down calories on that training schedule... i do a similar amount, eat like a horse and after about 10 months of steady weight loss have settled down now.
I guess some of it comes to what you're eating as well....
As above though, it depends where you are in the training, if you're new to it, it may well just be that you're converting excess body fat to muscle, thus your body shape/make-up is changing but you're not necessarily losing weight.
Newbie triathlete, serial researcher - tritriagain