Since the topic took a change to childhood obesity i will give my 2 cents.
I teach Physical Eduction at a high school in Southern California and we must meet state testing standards which consist of the mile run, push-ups, sit-ups, V-sit, trunk lift, and BMI (Body Mass Index-height/weight). New laws are soon going into place for the state of California that requires all freshman to pass this test, if they fail they need to continue to take Physical Education until they pass this test or graduate high school. They will have to be in P.E. every semester throughout their high school career if they don't pass, eating up their electives that they may rather be in.
Here is my districts problems: 70% of the students failed at the initial test. By the end of the second semester 50% of the freshman failed. If every freshman class continues with this high failure rate, there will be too many P.E. classes. Every student must take 2 years of P.E. and the ones that fail need to continue to take P.E there will be too many students for the limited number of teachers.
Further evaluation of the subject, the majority of the failure was coming from the BMI and mile run (the standards are not that hard). We started to find out what could lead to better results in the BMI. We had our students start a food log, they had to record everything they ate. It was truly disturbing...Our students eat the same pizza and burgers from our school cafeteria (70% of my students are on free or reduced lunch-so they have to eat at the school cafeteria).
Long winded story coming to a close-
We have alot of work ahead of us if we don't want to end up an obese nation.