Nightly News | September 21, 2012
>>> in health news tonight, this national campaign against large, sugary drinks, we all know the ones. the city of new york has been in the news for passing a ban that will soon go into effect, all aimed at the obesity epidemic. and tonight, there is new light shed on the connection. tonight, robert bazell , our chief correspondent.
>> reporter: dr. david ludwid and his team at children's hospital in boston counsel young people who are trying to lose weight .
>> now, it is apples, bananas.
>> sugary beverages can affect weight quite quickly, perhaps more than any food group .
>> reporter: he was one of more than 24 overweight or obese adolescents. half of the household got calorie- free drinks and were encouraged to give up sugary sweet beverages.
>> i got encouraged to always reach for the water, have it right by me.
>> reporter: after the year, the kids getting the non-calorie drinks gained four pounds on average, than those not getting it. the study concentrates on the emerging understanding on how some people are disposed to putting on weight.
>> people who tend to gain weight or become obese are much more likely to do so if they drink soda or sugar-sweetened beverages.
>> reporter: scientists increasingly believe that sugary drinks put on more weight than other same type of calorie food foods.
>> they may under mine the body's ability to regulate weight.
>> reporter: the american beverage association responded in a written statement, sugar-sweetened beverages are not driving obesity. they play a small and declining role in the american diet. many scientists say this latest evidence shows that role needs to decline even further. robert bazell , nbc news, new york.