The former president has clinched a deal via the Alliance for a Healthier Generation, a joint initiative of the William J. Clinton Foundation and the American Heart Association with the food manufacturers the Campbell Soup Company, Dannon, Kraft Foods, Mars and PepsiCo, to limit the amount of fat, sugar and salt in foods distributed to schools.

The deal comes just five months after a similar agreement targeted the sale of sodas in schools and places a limit of 35% of total calories coming from fat; elementary schools will have a limit of 150 calories on each non-nutritious snack.

In May, the alliance announced an agreement with beverage industry leaders to sell only water, unsweetened juice and low-fat and nonfat milk in elementary and middle schools.

Diet sodas and sports drinks are still sold in high schools and the agreement covers 87 percent of the soft drink market in public and private schools.

The agreement with the five food makers sets guidelines for fat, sugar, sodium and calories for snack foods sold in school vending machines, stores and snack bars under which most foods will not be permitted to derive more than 35 percent of their calories from fat and more than 10 percent from saturated fat.

There will be a limit of 35 percent for sugar content by weight.

This will effectively rule out such snacks as Snickers bar, which have 280 calories, 130 of them from fat and 30 grams of sugar.

The food producers have promised to change recipes so that more snacks meet the guidelines.

Childhood obesity has reached almost epidemic levels in the U.S. and has been blamed for an increase in early-onset diabetes and other illnesses.

Bill Clinton says the move will make a real difference in the lives of millions of children by helping them eat healthier and live healthier.

Another 34 million more are estimated to have low bone mass, placing them at increased risk for osteoporosis.

Over a million women in the UK have been diagnosed with osteoporosis, and many more may have the condition.

The researchers did find however that the calcium intake from all sources, including non-dairy sources such as dark leafy greens or beans, was lower for women who drank the most cola.

Professor Tucker and the team suggest an ingredient in cola called phosphoric acid might be responsible for the link, because phosphoric acid creates an acidic environment in the blood and calcium is then taken out of the bones to balance that out, but she says more studies are needed.

Experts note the findings but advise that eating a healthy diet with adequate amounts of calcium-rich foods, taking regular weight-bearing exercise, stopping smoking, and reducing consumption of alcohol, all help to keep bones healthy.

The research is published in the American Journal of Clinical Nutrition.