The tobacco manufacturers have long been vilified. More recently, brewers and shops that sell cheap booze have found themselves in the dock. Now steps forward a third party for condemnation, the manufacturers of food. Between them the three groups are held responsible for a set of illnesses that cause more deaths than all other causes combined.

These ailments have an inelegant name: non-communicable diseases – the ones you don't catch from someone else. You don't usually see them; these are the problems, often hidden, that people carry with them through their apparently normal lives until their conditions become death-threatening rather than merely life-shortening.

The main non-communicable diseases are heart disease, diabetes, cancers and chronic respiratory conditions. It seems obvious also to include obesity in this category, now officially a worldwide epidemic. But its consequences in terms of heart problems and diabetes are in the primary list. And it is obesity more than anything else that brings food manufacturers into the court of public opinion.

In a recent study, The Lancet, probably the world's leading general medical journal, stated that the obvious possible drivers of the obesity epidemic are to be found in the food system: the increased supply of cheap, palatable, energy-dense foods; improved distribution systems to make food much more accessible and convenient; and more persuasive and pervasive food marketing. These qualities are exactly what many people all over the world want. For whatever else they do, readily accessible food, alcohol and tobacco cheer you up. We feel better. That is one of the reasons why non-communicable diseases are such an intractable problem.

The most startling fact about them is that they are now responsible for more deaths than all other causes combined. In 2008, 36 million people in the world died from non-communicable diseases, representing 63 per cent of the 57 million global deaths that year. Death and disease from non-communicable diseases now outstrip communicable diseases in every region except Africa – which is catching up fast.

These figures mean that we are wrong to think that so-called lifestyle diseases are a feature of rich countries. In fact the evidence goes the other way: the wealthier and better educated you are, the less likely you are to succumb to a non-communicable disease. What we call lifestyle ailments are illnesses generated by the way poorer people tend to conduct their lives. The highest rates of blood pressure, for instance, are seen in Africa. When we discuss food marketing in this context, we really mean marketing to the vulnerable.

This is why the United Nations, during its General Assembly this week in New York, did something remarkable. It invited world leaders – represented by their health ministers – to debate the issues over two days. Mexico's Health Minister told the gathering that 14 people in every 100 adults in Mexico had diabetes. Among the measures recommended by delegates was one aimed straight at the food manufacturers. They should curb the extensive marketing to children, particularly on television, of foods and beverages that are high in saturated fats, trans-fatty acids, sugars, or salt.

Now a UN statement is no more than just an authoritative opinion. Two things speak more compellingly. One is an assessment of the costs of unchecked disease that fall directly on governments and more widely on economic activity. A second is the power of example in which another country, similar to your own, gets a grip on at least part of the problem.

As far as costs are concerned, the British Government has recently done the sums for obesity, just one of the non-communicable diseases. The figures are startling. In 2009, 23.0 per cent of adults and 14.4 per cent of children in England were obese. Moreover it is predicted that if no action were taken, 60 per cent of men, half of women and one-quarter of children would be obese by 2050. Can you imagine what that would be like? Every other man or woman who passed you in the street would be waddling along. And if you chanced to see children walking to school, a quarter of them would be Billy Bunters.

Direct costs to the National Health Service of the present incidence of obesity are estimated to be £4.2bn. These numbers ought to have an impact in the context of severe budgetary restrictions on government spending. Except that they don't seem to get through to Andrew Lansley's Department of Health.

This is how the Government describes its policy in the face of the obesity epidemic: "We want people to know that they can change their lifestyle and make a difference to their health. What the Government can do is give the public clear, consistent messages on why they should change their lifestyle, how to do so, and put in place ways to make this easier."Yes, that is it. All of it.

As an example of what can be done, take the case of trans fats, widely used in the food industries. These tend to extend the shelf life of manufactured food and can even impart an appetising taste. But they also increase body fat for a given intake of calories, and health authorities everywhere recommend their consumption should be banned or reduced to small amounts. Denmark introduced laws strictly regulating the sale of foods containing trans fats in March 2003. Switzerland followed in April 2008. In this country Sainsbury's has, on a voluntary basis, stopped using trans fats in their own brand goods. But our Government remains inert.

Yet here is the power of example. It comes from New York. First the City tried to persuade food suppliers and thousands of restaurants to reduce their use of trans fats close to zero. They took no notice. So in December 2006, the New York City Board of Health banned the use of all but tiny amounts of trans fats in restaurant cooking that would, as The New York Times predicted, "transform the way food is prepared in thousands of restaurants, from McDonald's to fashionable bistros to Chinese take-outs". It worked. Trans fats have disappeared from the New York restaurant table. This is the sort of action food manufacturers are going to have to learn to live with. For the health lobby is going to keep striking them hard. And sooner or later, the British Government will wake up.

a.whittamsmith@independent.co.uk