Last month in Boston, a small conference took place that should send a chill through the food industry.

About two dozen lawyers and activists planned how to wage a legal war against obesity with the law-suit as their most potent weapon.

After tobacco, it is clear that food is the next target of litigation.

The thrust of the argument is likely to be that some food makers do not label their products clearly so consumers are not aware of the calorific value.

It is also claimed that the marketing of unhealthy food is aimed at children.

Kraft, the biggest food manufacturer in the United States, has just announced that it will limit the size of its portions of cheese and other products, and put much more nutritional information on packets of its wide range of foods, like the famed Oreo cookies.

'We think it's the right thing to do for the people who use our products. If along the way, these steps discourage a plaintiff's attorney, that's fine with us,' a Kraft spokesman said.

The United States Surgeon-General, the highest medical official in the land, reckons that obesity among adolescents has tripled in the past 20 years.

It is also reckoned that there are about 40 million obese adults, double the number of the 1980s.

Consumer responsibility?

But the battle in the courts will be over whether food makers are responsible for that rise in fatness or whether food eaters should take responsibility on themselves.

Eight obese teenagers, for example, filed a suit in New York against McDonald's.

One of them ate two meals a day, five days a week in its fast-food restaurants for four years and attained a weight of nearly 20 stone (270 pounds) despite her five-foot-six inches.

The allegation in court was that the plaintiffs were not aware of the unhealthiness of McDonald's products.

They alleged that some foods had 'addictive qualities'.

The claim, however, was dismissed but then refiled as an allegation that the food was not accurately represented when it was advertised.

The other big case involved Kraft, the subject of a suit filed in California to stop the company from marketing Oreo cookies to children.

It was then withdrawn, with the lawyer saying the publicity had made people aware of the health issues.

Labelling products

The food industry argues that people know that burgers or biscuits are not low-calorie health foods and that it is for the consumer to show some sense.

Companies may be vulnerable, though, if they do not clearly indicate the ingredients of products.

That may well be why Kraft has said it will spell out the contents of its foods.

That way nobody can claim that they did not know that, let us say, cheese or biscuits were high calorie.

But that does not mean the claims for past corporate practices will go away.

Lawyers have the bit between their teeth.