While some people do gain weight from having an increased appetite, it doesn't mean you necessarily will.
My own weight stayed about the same while marathon training
Myth #2 You will lose weight
Some people do lose weight training for a marathon due to the increase in working out.
But if you're goal is to lose weight I'd recommend focusing on strength training rather than running a marathon.
Myth #3: You will lose some toenails.
Yes, it can happen!
But I can also say that it didn't happen to me!
Myth #4: You Have To Be a Fast Runner
You don't need to be FAST to run a marathon.
Don't let that hold you back if you've always wanted to conquer this goal!