I was a vegetarian, then a vegan, for a long while. I felt healthy and energized as a vegan, because I made sure to eat a balanced diet with sources of protein, fibre, minerals and vitamins etc. I did take iron too, but even many meat eaters require iron, I never actually tested for iron levels though so maybe I didn't even need it. I also lost loads of weight but I was also counting calories but always kept at 1800 so I was eating loads.
It also taught me to cook and appreciate ingredients more.
I eat meat again, though I avoid it and don't tend to buy it for myself. I think being a vegan made me more healthy because it's hard to find cakes and stuff and forces you to cook from scratch more. I had to think about food choices. I don't think being a meat eater is necessarily more healthy, and vice versa. It bugs me when people instantly assume that vegetarians and especially vegans must be anemic and weedy and lacking in nutrients.