I'll preface my answer by saying that I'm not a health expert of any sort. That being said, I don't believe that mai fun noodles themselves are unhealthy. As far as I know the noodles are simply rice based noodles that are relatively low in fat. If you're not overdoing it on the portion size, they can certainly be a part of a healthy diet even if you're eating them several times a day. You also mentioned combining them with other ingredients like the veggies which sounds like a good strategy for keeping the noodle portion on the smaller side. I'd also suggest adding a source of protein to the meal as I believe that protein helps to keep your appetite in check for a longer period once the meal is finished. Most mai fun noodles are also gluten free although some unorthodox producers add other non rice starches to them so people following a gluten free diet are advised to check the ingredients to make sure they are gluten free.