I don't think so...If you're generally healthy there should be no problem...
If anything, your size can be important when it comes to choosing the airplane you're doing the PPL in, some people just cant fit inside a Cessna 152 comfortably..
Anyway i'd advise you to do the medicals before you start investing money and time and enthusiasm on being a pilot ( but that's not because of the weight, it's just good advice for anyone..).
And have fun flying!