Diet or Exercise, which is more important?

Hello
So, I know to loose weight (especially a large amount like I am) you must have a healthy and controlled diet but also you should exercise. What I am wondering is if the exercise is really vital in weight loss or do you think it is just for heart health and toning up?
I am currently very overweight and still have 50lbs left to loose (70 total goal). Here is my story:

I have been very active my entire life, played multiple sports as a kid, and as an adult took up running, biking, and going to the gym several days a week plus having a mini gym of my own at home. I have ran a half marathon and bike my commute in the summer which is 22miles a day. My friends and family are always amazed at how active I am. Also, I have always been a pretty healthy eater. I didnt eat meat, most of my diet consisted of vegetables, fruit and protein bars. but, I did allow myself to indulge in baked goods or desserts several times a week. but my thought was that it didnt matter because I burned so many calories!
Despite all of this I have been severely overweight my entire life and I hit a new high this year! :(

Well, once I saw that number on the scale I freaked out and decided I had to change what I was doing because obviously it wasnt working. I decided to drop the "extreme workouts" and focus on my diet. I incorporated meat back into my diet and dropped all gluten, wheat, and dairy out of my diet. I have been doing casual biking, hitting the elliptical and doing lower impact classes at my gym. That was under 2 months ago and I have dropped 20lbs!

So, I am convinced that diet is what I need to continue to focus on! I would love to hear everyone's thoughts, experiences and any recommendations :D I know everyone is different but thought maybe my story would help someone or spark some good conversation!