THE BRONX - Mayor Michael Bloomberg's proposed ban on large sugary drinks may be picking up steam. Weight loss groups Weight Watchers and Jenny Craig have announced support for the proposal, which calls for public venues to stop selling sodas larger than 16 ounces. Bloomberg says the groups join a number of physicians and elected officials who support the plan. Many business owners and several members of the City Council say they're skeptical toward the measure. The Board of Health is expected to vote on the issue Sept. 13.