Industry giants Coca-Cola, PepsiCo and Cadbury Schweppes were among those who signed up to a deal with the Clinton Foundation and American Heart Association to make sure only lower calorie and nutritious beverages would be sold in US schools.
Soft drinks firms have come under intense pressure to curb marketing and sales to children as America grapples with its obesity crisis.
The new deal, which builds on the American Beverage Association's voluntary restrictions on fizzy drinks in elementary and middle schools last year, comes after months of talks between soft drinks firms and lawyers.
Professor and lawyer Richard Daynard, who was involved in the negotiations, told BeverageDaily.com the threat of class action lawsuits was crucial in brokering a deal with soft drinks firms.
"It is a tribute to litigation. When we started negotiating with them they weren't anywhere near this," said Daynard, a veteran in lawsuits against tobacco giants and who had spent most of 2005 helping to prepare legal action to get soft drinks out of schools in several states.
Fizzy soft drinks, in particular, have been singled out as a major contributor to America's child obesity problem by both studies and health professionals.
The presence of soft drinks in schools has, as a result, become a main concern. Nearly half of all US schools had an exclusive, so-called 'pouring rights' contract with a beverage company in the 2003-04 school year, according to a report published by the US Government Accountability Office last August.
Several US states have begun taking matters into their own hands.
A total of 38 school nutrition bills aiming to get junk food out of schools were introduced last year, while the governor of Connecticut this week backed proposals to ban sugary soft drinks from all state schools there.
State Senate president Pro Tem Donald Williams, who sponsored the legislation, estimated that soft drink and vending companies spent more than $250,000 lobbying against the bill out of concern that it would set a national precedent.
The voluntary agreement signed by soft drinks firms this week is an attempt to fend off the need for legislation and legal action.
It means that by the 2009-2010 school year there should be no beverages containing more than 100 calories sold in American schools, except for certain milk and juice drinks.
The move has been widely praised by various groups, from ex-president Bill Clinton to campaigning bodies involved in lawsuit preparations, such as the Center for Science in the Public Interest (CSPI).
Still, the CSPI and some lawyers involved in litigation efforts also offered words of caution last night.
Daynard said the omission of sports drinks in the agreement could be a big loophole. "We might have to re-hone litigation if this becomes a problem," he said, adding that sports drinks essentially amounted to sugared water, and should not be marketed at children sitting in class most of the day.
There were also concerns that regular fizzy drinks may simply be replaced by diet varieties by 2010, according to the lawyer Ross Getman, who has campaigned against soft drinks in schools and who's independent testing re-alerted the Food and Drug Administration to the presence of cancer-causing chemical benzene in drinks last autumn.
"Diet soda is not a healthy product," he said.
Then, of course, there is the benzene issue. Several Lawsuits have now been filed against soft drinks firms alleging they have drinks contaminated with benzene above America's legal limit for benzene in drinking water.