There are a few problems with this line of reasoning. Your argument assumes several things which are not explicitly stated. It would be more precisely phrased as "How cheap, widely available teleportation will worsen the obesity crisis." The internet didn't slash the music industry, relatively cheap broadband connections with "unlimited" bandwidth caps slashed the music industry. Do you know how much it would cost to fill an iPod on a dial up connection with their usage rates? Do you know how long it would take?
Now, working on the presumption that aforementioned teleportation is both readily available, and cheap I still don't see much of an argument. Modern comforts don't actively preclude or dissuade people from remaining physically active (we're not in the Matrix, yet). The domestication of horses didn't stop people from walking if they so chose, neither did the invention of the automobile. The only thing that really led a lack of these things to cause an increase in obesity was overwhelming amounts of ignorance on personal fitness.
I also think that by the time such teleportion reaches a point where it would be used instead of HotPockets, we would have hopefully educated the world on how to remain fit and the importance of such a state on quality and length of life.