You take the D train from Manhattan, in part because cabbies cringe when you mention the Bronx, but mostly because the cab fare would set you back. You hunker down hoping that when you surface at Kingsbridge station, the sun will have broken through and the fruit guy will be standing at the exit, with his cart of ripe pineapple and bananas. The memory of mango and papaya is making your stomach rumble, and it cranks up a few decibels when a young man walks into the carriage hawking candy bars. He's got M&M's and Snickers, which he's peddling 'in the name of Jesus'. You're wondering what Jesus would have thought about eating M&M's for breakfast when the automated conductor announces your stop, and you step out and up the stairs to the street. No sun, no fruit guy. You walk a few blocks toward the main drag, Jerome Avenue. Signs on store fronts promise tacos and egg rolls, but the windows are dark and the doors bolted. You keep walking towards a pair of golden arches stretching right down to the pavement, like a halo. You step inside and feel the warm rush of regulated airflow and see the friendly counter kids ready to serve. And you know, right then, that you may not have found Jesus, but you have found lunch.

Jazlyn Bradley knows the Jerome Avenue McDonald's well. She once lived nearby, in a two-bedroom apartment with holes in the walls and lead paint dust flaking from the window frames. There was no kitchen sink, so the family washed dishes in the bathtub. Often, they ate at McDonald's. Then Jazlyn moved to a shelter, and McDonald's became not a home away from home, but home. It was bright, well-lit, and safe, with clean bathrooms and friendly people. And while most other things in Jazlyn's life were unpredictable and transient, McDonald's was steady, always there for her. She went every day, sometimes several times a day. And she ate. She started with the Happy Meal. As the years passed, she ate deep-fried chicken nuggets, fried fish sandwiches, double-fisted burgers with cheese and sauce and bacon, French fries and chocolate shakes. Just like the TV advertisements suggested, she started her day with a breakfast sandwich, 'super-sized', with a biscuit, sausage, egg and cheese. She'd wash it down with a Coke and head for school. In Jazlyn Bradley's world, a world where people live without kitchen sinks, McDonald's is a happy, comfortable place.

Jazlyn is 20 years old, but has the medical profile of a middle-aged woman: diabetes, hypertension, and high cholesterol levels. She is five foot six and 270 pounds, which is nearly double the weight she should be. Her sisters, 18-year-old Shakima and 14-year-old Naisia, are also obese, as is their dad, Israel, who walks with a stick. Clearly, their obesity has a genetic component, but genetics don't work in a vacuum. Something triggered the Bradley family's tendency to accumulate poundage, but until they met Samuel Hirsch, they weren't sure what that might be.

A personal injury attorney, Hirsch visited the Bradleys at home (regarding a different matter to the one he would pursue) and was struck by the lack of cooking facilities, and by their reliance on fast food. Israel Bradley told him that his family went to McDonald's nearly every day. They loved the food. But Hirsch convinced the Bradley family to join a class action suit, Pelman versus McDonald's Corporation, alleging that McDonald's engages in practices that make kids fat.

Samuel Hirsch says he took the McDonald's case for money, as he does every case. Children were not always at the centre of Hirsch's litigious soft spot. His first crack at fat was through Caesar Barber, a 56-year-old maintenance worker. Despite high blood pressure, diabetes, two heart attacks, and repeated warnings from his doctor, Barber continued to eat at Wendy's, KFC, McDonald's and Burger King four to five days a week. Knowing that big corporations have deep pockets, Hirsch filed suit against all four restaurant chains, and when the suit attracted media attention, he cruised the talk show circuit in a vain attempt to drum up public sympathy for his client. But last year his case famously fizzled in the court of public approval. Still, it made Hirsch rethink his strategy. He thought the way to win this case was through America's heart. And the way to reach that heart was not through adults, who are expected to know that fast food is bad for them, but through kids. Rather than going after several fast food conglomerates, Hirsch decided to concentrate his efforts on McDonald's. And he focused on the company's advertising campaigns that targeted children.

On the McDonald's website, the company's commitment to community, charity, animal welfare, environmental responsibility and even childhood immunisation is dutifully proclaimed. But a click of the 'Happy Meal' option paints a totally different picture, with animated clips of toy premiums like the '8 Dolls with a Passion for Fashion' or 'He-Man and the Masters of the Universe'. Interspersed are soothing reminders of the 'wide range of high-quality foods that can easily fit into a healthy, balanced diet', and, not incidentally, of the restaurant's 'new premium salads'. The salads made their appearance shortly after the company's stock plunged, and sales declined for the first time in its 47-year history. In the Jerome Avenue outlet, salads are on offer, but they are not a hot seller. One customer, waiting in line for a Happy Meal for her kid, demands to know why a salad sells for almost five bucks which will also buy five double cheeseburgers.

Most customers go to McDonald's restaurants looking for value, defined by the company itself as 'big' and 'satisfying'. Under that definition, a value meal is hard to beat, especially when super-sized and delivering three-quarters of the recommended adult calorie allotment and more than three-quarters of the recommended daily limit of fat. And that's before dessert, which on Jerome Avenue might be the 'two for a dollar' baked apple pie, or the chocolate triple thick shake, the super-sized version of which contains nearly 1,200 calories and more than a quarter pound of sugar.

One can, of course, piece together a reasonable meal at McDonald's, though that presumes knowledge that many people do not have. McDonald's makes a point of baring its nutritional soul on the Internet, but it is up to each franchise to determine how nutritional information is displayed. The obvious solution is to post nutrition information prominently, either next to the menu board or directly on the packaging of each item. But in public statements McDonald's has been dismissive of this option, contending that it would be both confusing and patronising to customers.

Few legal experts believed that Pelman v. McDonald's Corporation would win on the first round, and they were right. Robert Sweet, a distinguished district court judge of the Southern District of New York, dismissed the class action suit in January, and McDonald's loudly proclaimed a victory for common sense. 'Every responsible person understands what is in products such as hamburgers and fries, as well as the consequence to one's waistline, and potentially to one's health, of excessively eating those foods over a prolonged period of time,' the company's lawyers said, adding that it would be impossible to prove whether eating at McDonald's was a major cause of the girls' ailments.

But legal scholars, being scholars, were more circumspect. Some interpreted Sweet's verdict as the opening volley in a battle against fast food that could turn into a full-fledged war to be fought not only by Hirsch, but also by the top legal minds in the country. Among Sweet's more poignant observations was that 'Chicken McNuggets... are a McFrankenstein creation of various elements not utilised by the home cook' and that 'it is hardly common knowledge' that 'McDonald's French fries are composed, in addition to potatoes' of a myriad other ingredients. Speaking directly to Hirsch's charge that 'McDonald's products are inherently dangerous in that they are addictive', Sweet wrote that such a claim 'does not involve a danger that is so open and obvious, or so commonly well-known, that McDonald's customers would be expected to know about it. In fact, such a hypothesis is even now the subject of current investigations.'

Sweet's decision, essentially a blueprint for refiling the case, was extraordinary by any judicial standards but his own. He has a 25-year history of championing controversial causes from the bench. He is particularly proud of the supporting role he played in the ongoing asbestos litigation, which, at an estimated $200 billion, is projected to be the most costly class action product liability settlement in history.

'One of the interesting aspects of this case,' he said before he threw it out for a second and final time last month, 'is that while government regulates what's in processed foods - say cheese in the market - there is an exception for restaurant foods. It's a loophole. The Nutrition Labelling and Education Act (passed in 1990) requires the identification of everything in processed foods, but there is this restaurant exemption. There is also the question of deception. What level of knowledge should an ordinary person have about a given product? If there were studies that showed that a given food had a deleterious effect - say on your metabolic processes - and that the product was not adequately labelled, well that would be interesting, wouldn't it?'

Yes, very interesting, but Pelman v. McDonald's did not address these issues. Lawyers might have got excited by the judge's summing up in January, but last month Judge Sweet dismissed Pelman v. McDonald's , and ruled the plaintiffs could not refile the lawsuit. In summing up he said: 'The plaintiffs have made no explicit allegations that they have witnessed any particular deceptive advertisment, and they have not provided McDonald's with enough information to determine whether its products are the cause of the alleged injuries.'

Critics of Hirsch say he relied too heavily on a claim of false advertising. George Washington University law professor John F. Banzhaf III, well known for his work on tobacco litigation and an ideological crusader for fast food litigation, says that the attorney even used an example of an advertisment that was shown 'before the kids were born'. Banzhaf says that this was one of eight cases against food companies. 'We've already won five out of eight - the last one was several months ago, against a manufacturer of fattening ice cream. The dismissal of this case will not deter the filing of additional lawsuits. Indeed, the judge's original opinion spelled out at least two winnable legal theories under which law suits could be brought and, since they were not included in the law suit, they remain for use in subsequent legal actions. These include arguments that McDonald's failed to advise customers of the risks which were common knowledge - such as the dangers of eating a 'McFrankestein' [Judge Sweet's description] Chicken McNugget - and the failure to warn that eating fattening foods can cause addictive-like effects similar to nicotine.'

McDonald's statement after the judge's ruling, made the point that the company does not feel it is responsible for people's personal eating habits and what makes them fat: 'We trusted that common sense would prevail in this case, and it did. The dismissal is further recognition that the courtroom is not the appropriate forum to address this issue.'

Banzhaf disagrees. 'In the mid-1960s, smoking was considered a private health problem. It took five to 10 years to see it as a public health problem, both through the issue of secondhand smoke and because smoking was burning a hole in the public pocket book. It took another 10 years, and 700-800 legal actions, to convince a jury.'

Most Americans are against obesity litigation, just as most Americans are against anti-smoking litigation. They consider eating, like smoking, a matter of choice, and like the tobacco industry before it, the food industry has worked hard to convince us that limiting choices is what litigation is trying to accomplish. The fast food industry, Banzhaf says, has left itself vulnerable by not providing consumers with enough information to make informed choices.

'McDonald's gives out toys in Happy Meals, and these toys come with warnings about choking hazards, because the company knows that if it didn't include a warning and there was a problem they could be sued,' he says. 'But how many people know that in America a Mighty Kids Meal has 800 calories and more than half the amount of saturated fat that an adult should have in a day? This in a meal targeted to children?'

Michael Lowe, professor of psychology at Drexel University and research associate at the Renfrew Centre for Eating Disorders, agrees that the scientific case against fast food is building. Scientists have known for decades that the more food available, and the more variety of food available, the more people will eat. But what's new, Lowe says, are studies suggesting that perceived variety is equally effective at promoting overindulgence as actual variety. When sugar water is delivered to rats from five different bottles, they drink significantly more of it than they do when the same amount of sugar water is offered from a single bottle. Extrapolating this to humans by offering us variations on the high-fat, high-salt, highly sweetened theme, McDonald's and other fast food outlets have all but set many of us up to overeat. 'The industry wants us to think that self-regulation - willpower - is what we should focus on for the prevention of obesity,' Lowe says. 'My take is that self-regulation in this environment is important, but not sufficient. The food industry has already taken some steps to obscure this issue that are not too different from what the tobacco industry did when it argued that nicotine was not addictive.'

The food industry would like us to believe that so many of us are fat today because we're lazy and greedy and life is easy and food is cheap, but that doesn't really explain the phenome non. Segments of the population have for centuries had access to large quantities of palatable, fattening food, and were presumably as greedy as we are, yet most did not grow fat. Indeed, just a generation ago, less than 15 per cent of Americans were obese while today that figure is at 30 per cent and rising. In children, obesity rates jumped from 6 to 15 per cent in just two decades. Obesity is on the rise in other nations where Western-style commerce - and in particular fast food - has taken root. One in 10 British children under five is now obese.

Scientists do not buy the argument that people have, in half a generation, become greedy and lazy, nor do they believe a change in our genes has made us fat.

'Our relationship with food is extremely complex, and we are still in the infancy of understanding. What we do know is that we live in an environment that has stimulated whatever genetic tendency we have to overeat,' says Antonio Tataranni, head of the obesity, diabetes and energy metabolism unit at the National Institutes of Diabetes & Digestive & Kidney Disorders.

The critical question, of course, is whether habitual exposure to foods that are unnaturally high in calories, fat, and sugars can in some sense addict us, in the sense that narcotics do. Addiction is a slippery concept but it is generally agreed to be a chronic compulsion to seek out and use an unhealthy substance that when withdrawn results in anxiety, irritability and craving.

For years Big Tobacco argued that its products were not addictive, but merely seductive. It took several decades for science to prove that nicotine is one of the most addictive substances on the planet and that some of us more than others are susceptible to its spell. Eating is different in that it is one of the most common and natural sources of pleasure in everyday life. Many people of normal weight believe that they are in some way 'addicted' to particular foods, like chocolate, when they most certainly are not. But evidence is surfacing that for some people certain foods may be addictive, though perhaps not in the way we become addicted to nicotine.

Not everyone who smokes becomes addicted to nicotine, and clearly, not everyone who eats becomes addicted to food. But recent insights into the genetic underpinnings to obesity make certain that some of us are more prone than others to becoming overweight and that this predisposition is probably linked to pathways in the brain that control appetite. Scientists have found that these pathways can be changed by diet, and that sugars and fats consumed in high amounts seem to short-circuit the normal satiety systems in vulnerable people, making them unable to determine when they've had enough to eat.

Rockefeller University neurobiologist Sarah Leibowitz has found that animals that consume more than 30 per cent of their diet in fat have an elevated desire for fat on a physiological level. Given that obese people generally consume more than 30 per cent of their diet in fat, this might help explain why obese people seem to favour fast food, which is dense in fat. And John Blundell, research chair in psychobiology at the University of Leeds in England, says that fat delivers such a dense package of calories that it overrides the body's system to sense satiety.

Of course desiring a certain food or having a high capacity to eat it does not connote addiction. But Gene-Jack Wang, a physician and expert on brain imaging at the US Department of Energy's Brookhaven National Laboratory in Upton, New York, has compared PET scans of morbidly obese patients with those of drug addicts. The brains of drug addicts have fewer receptors than non-addicts for dopamine, a neurotransmitter that provokes feelings of pleasure and satisfaction. Addictive drugs increase dopamine levels, and it is in part this effect that a junkie seeks in a fix. Food - or at least glucose, which the body depends on for fuel - seems to have the same effect. Scans show that, like drug addicts, obese subjects have fewer dopamine receptors than normal weight people do. Wang suggests that these people may overeat for the same reason drug addicts shoot up: to stimulate an underactive dopamine system and feel the pleasure that those with the normal number of receptors experience naturally every day.

'Sometimes we eat food even when we are not hungry, so there has to be some sort of brain mechanism in place that makes us eat when we don't need to,' he says.

Bart Hoebel, a professor of psychology in the programme of neuroscience at Princeton University, says that palatable foods bear many interesting similarities to addictive drugs. Hoebel has shown that rats deprived of food for 12 hours and then allowed free access to sugar water and food double their sugar intake in 10 days, as well as experience long-lasting central nervous system changes quite similar to those shown by rats addicted to narcotics. When these same rats are deprived of sugar entirely, though still given food and the full allowance of vital nutrients, their teeth start to chatter, and their bodies shake. 'This pattern of fasting and then eating large amounts of sugar is not uncommon in humans,' he says. 'The experiment implies that if you skip breakfast repeatedly and drink a soda mid morning, that could set you up for addiction. We know that binge drinking promotes alcohol addiction; we want to know whether binge eating can do the same thing to susceptible people.'

American doctors have for years observed the reliance on fast food of overweight and obese people. Charles Billington, professor of medicine at the University of Minnesota and associate director at the Minnesota Obesity Centre, says that some of his patients become uncomfortable when deprived of certain foods, particularly fast foods, which they tend to crave. 'Children don't like strong flavours, so they really go for this flavourless sweet, fatty stuff,' he says. Being exposed to this over a period of years, they become entrained, and this preference persists into adulthood.' The fatty, sweet options offered by fast food restaurants seem almost preordained to tip the balance of human satiety, and just about everything on the menu offers some variation on this theme.

Psychologist Donald Williamson says the food industry knows it is habituating children to sweet, fatty food, and that this in fact is its goal. 'Frankly, it's industry's business to get us to eat more food, not less.'

Fast food companies like McDonald's can hardly be unaware that its products and its advertising are attracting hordes of eager converts, but this is neither nefarious nor illegal, regardless of the health impact. But when the first fast food case does go to trial - and most attorneys in America agree it is a matter of when, not if - lawyers will have the opportunity to root through memos, e-mails and files, to discover, as Sweet put it, 'who knew what, and when'. It is this 'discovery' that the fast food industry should fear most.

THIS IS AN EDITED VERSION OF AN ARTICLE FROM SEED MAGAZINE

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