WASHINGTON — A 54-page petition filed with the Food and Drug Administration by the Centers for Science in the Public Interest details what the group calls “substantial scientific evidence that added sugars, especially in drinks, causes weight gain, obesity and chronic diseases.” The group is asking the F.D.A. to establish a safe limit of sweeteners in soft drinks.

The American Beverage Association responded to the petition and said that, “Everyone has a role to play in reducing obesity levels — a fact completely ignored in this petition. This is why the beverage industry has worked to increase options and information for consumers.”

Public health departments lending their support to the C.S.P.I.’s petition include the cities of Baltimore, Boston, El Paso, Texas, Kansas City, and Philadelphia.

“The F.D.A. should require the beverage industry to re-engineer their sugary products over several years, making them safer for people to consume, and less conducive to disease,” said Michael Jacobson, executive director of the C.S.P.I.

The F.D.A. classifies sweeteners such as high-fructose corn syrup, sucrose, and other sugars as “generally recognized as safe,” but to be GRAS, there must be a scientific consensus that the ingredient is safe at the levels consumed, according to the C.S.P.I. The petition contends that the current scientific consensus is that added sugars are unsafe at the levels consumed. The petition asks the F.D.A. to determine what level of added sugars would be safe for use in beverages, and to require those limits to be phased in over several years. The petition does not propose a specific safe level, but noted that several health agencies identified two-and-a-half teaspoons (10 grams) as a reasonable limit in a healthier drink.

In 1982 and in 1988, the F.D.A. said it would undertake a new safety determination if sugar consumption increased, or if new scientific evidence indicated a public health hazard. Both of those conditions have been met, according to the C.S.P.I.