Can a teen lose 29 pounds in a month?

Too many factors to take into consideration. Probably not in any healthy way. It is very possible to lose about half that. Typically a first week of a diet will cause a great deal of water weight to be shed. For a 250 pound man, it wouldn't be unusually for them to lose 15 pounds in the first week of an Atkins diet and 3 or 4 pounds a week the first month. After that it will slow down a great deal. A teen, not likely to be over 175, you could see maybe half that, but it could have long term affects. You didn't gain 29 pounds in a month, don't expect to lose it in a month. unless you seriously consider lyposuction or amputation