Weight wise, despite what between the lines reading of the paper suggests the authors wanted to find, they were unable to conclude that after school sports had a beneficial impact on weight status. While there were some studies that suggested benefit, there were many others that did not, leading the authors to ultimately state,
"there is not sufficient evidence to conclude that sport participation protects against the development of obesity"So why might that be? After all, it may be fair to assume that kids who play after school sports are more active than kids who don't and consequently burn more calories. In fact according to this review paper, that'd be true in that to date the data would suggest that kids in after school sports are in fact more active overall than kids who aren't (they cite one study that used accelerometry to suggest a 30minute daily difference in physical activity due to organized sport).
But if they're burning more calories, why aren't they lighter?
Well, if they're burning more but aren't lighter, it'd probably follow they're eating more. And indeed, that's what the research also suggests with extra calories in after school sports participants coming from sugar sweetened beverages (can you say, "Gatorade"?) and from fast food (can you say, "Drive-Thru"?).
Now bear in mind the review didn't have that many papers to draw upon, and the results consequently aren't the most robust, but if my patients' and my family's experiences are anything to base things on - many families will hit drive-thrus or take out so as to allow for rapid transit to after school sports and it seems as if a child simply setting food on a blade of grass buys him or her some sort of sugar sweetened treat at game's end.
Who said fixing this problem was going to be simple?
Nelson TF, Stovitz SD, Thomas M, LaVoi NM, Bauer KW, & Neumark-Sztainer D (2011). Do youth sports prevent pediatric obesity? A systematic review and commentary. Current sports medicine reports, 10 (6), 360-70 PMID: 22071397