Sodas causes one to gain weight, said the advocacy group US Right to Know after looking into results of a research on artificially sweetened products. The group has urged federal regulators to see if manufacturers including Coca-Cola and PepsiCo are doing false or misleading advertising.

The research has showed that diet soft drinks and other artificially sweetened products are related to weight gain.

Citizen petitions were filed by the group on Thursday to force US Food and Drug Administration and the Federal Trade Commission to stop those companies from doing branding of artificially sweetened products with the word 'diet'.

"Consumers are using products - Diet Coke and Diet Pepsi - that are advertised to make us think they assist in weight loss, when in fact ample scientific evidence suggests that this is not true, and the opposite may well be true", said the petition to the Food and Drug Administration.

The assertions in the petition have been strongly challenged by the American Beverage Association. The association has come in support of the Coca-Cola Co., PepsiCo Inc. and other soft-drink makers, saying diet beverages are instead helpful in implementing an overall weight management plan.

An alliance was also formed by the beverage association, Coca-Cola, PepsiCo and the Dr Pepper Snapple Group, last fall with the Bill, Hillary and Chelsea Clinton Foundation for conducting a program to battle with obesity by reducing the amount of calories in beverages used in American diet. The soft drink makers also decided to increase the sales of lower-calories drinks.

The petitions filed on Tuesday asked for investigation into the marketing of products that are made using any artificial sweeteners.

Concerns have been raised for decades over the safety of using a number of artificial sweeteners, especially NutraSweet and its predecessor, saccharin. Many recent studies have dispelled the belief that non-caloric sweeteners help in weight loss.