DURING MY 1970s childhood, we survived on a diet of pure saturated fat. We gorged eggs, pork and burgers fried in butter or lard. A favourite treat was a certain hamburger chain's thick milk shakes that were essentially chunks of lard flavoured with strawberry, banana or chocolate. Then along came the 1980s and suddenly everyone understood that a diet of saturated fat (that is, fat that's solid at room temperature) was a ticket to a heart attack. Like so many people, I cut back on animal products and became a disciple of soya oil and olive oil - preferably extra virgin - which I still use. Wrong move, according to two US dietary experts Mary Enig and Sally Fallon. In their controversial book, Eat Fat, Lose Fat: Lose Weight and Feel Great, Enig and Fallon claim that so-called healthy vegetable oils are a major cause of obesity. In contrast, the saturated fats normally considered harmful, such as those found in red meat, butter and coconut oil, promote weight loss and health, they say. 'Creamy sauces, buttered vegetables, and ice cream taste good for a reason,' they write. 'It's not that your body is trying to torment you by making unhealthy foods seem delectable. 'Instead, your body is using your taste buds to signal what you need. That's why most of us enjoy rich foods, like succulent lamb chops, berries with heavy cream, and crispy turkey skin. But because we believe that fats are bad, we are afraid to listen to our bodies.' They say delicious, fatty foods are 'nature's gift to us'. On paper, the evidence in favour of saturated fats looks strong. Consider the French. Their diet is choked with saturated fats in the shape of butter, eggs, cheese, cream, liver, meats and rich pates. Nevertheless, as has been publicised in a series of recent media reports, the French have a lower rate of heart disease than many other western countries. Barry Groves, a nutritionist who runs the International Network of Cholesterol Sceptics, claims that the eating trends of several other countries show the benefits of animal fat. He cites Japan, where intakes of animal fat have supposedly more than doubled since the second world war. In that time, the nation's incidence of coronary heart disease has fallen consistently. Likewise, until recently, the Indian population had low levels of heart disease while using ghee (clarified butter), coconut oil and mustard seed oil, all of which are heavily saturated. According to Groves, the epidemic of heart disease in India began only after the substances listed gave way to peanut, safflower, sunflower, sesame and soyabean oils. Further evidence for the benefits of saturated fat comes in the shape of the Framingham Heart Study. Begun in 1948, the study involved 6,000 people from the town of Framingham, Massachusetts. Researchers split them into two groups: those who consumed little saturated fat and those who guzzled it. The researchers tested the volunteers every five years. In 1992, the director of the study, William Castelli, dropped a bombshell when he made this announcement: 'We found that the people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active.' Groves says it's time to change how we think. 'Half a century of study has demonstrated clearly that saturated fats are, in fact, the healthy fats and that it's the polyunsaturated fats that are the damaging ones,' he says. 'However, by the time this became clear in 1970, doctors had been telling people to cut down on saturated fats to prevent heart disease for so long that they couldn't reverse their advice without risking losing face and credibility. They still dare not.' The power of this argument with its conspiracy overtones is so hard to deny that you may be tempted to embark on an orgy of illicit feasting. Farewell, steamed veggies; welcome back egg roll, dumplings, meatballs and batter-dipped pork. But not so fast. Most experts remain sceptical about the virtues of animal fat. Enter Fred Pescatore, a US doctor and author of four health and nutrition books. On one hand, Pescatore defines himself as a big Enig fan, and agrees that 'sat fat has gotten a bad rap'. On the other, he says Enig has missed the boat with her latest book. 'Saturated fat in study after study done on the way people eat has been proven to be lethal,' he says. 'Perhaps if we consumed nothing but coconut oil, then we'd be OK. But we don't in fact live our lives that way. We eat more than one type of fat and when saturated fat is mixed with others, it makes us unhealthy.' Pescatore accuses Enig of failing to take a wider view. 'In her strong take on sat fat, she's doing exactly what she accuses her enemies of doing - which is to not look at the entire picture but to isolate one nutritional component.' Elizabeth Somer, author of The Origin Diet and Food and Mood is equally critical. 'While I admire much of Dr Enig's past work, she's completely off-base if she's saying that saturated fats are in any way healthy. Thousands of studies spanning decades of research show that these fats are major contributors to disease risk. 'Our bodies evolved on diets low in saturated fats, so it makes sense that today, our high-saturated fat diets are as alien to our bodies as drinking motor oil.' Somer's point that animal fats are foreign to our species is the basis of a widely credited, persuasive theory rooted in the Stone Age. During that era, people were hunter-gatherers who lived on lean wild meats, fish, vegetables and fruits. These foods gave our ancestors the go they needed. At the same time, the human genome became inextricably entwined with the fats, proteins, carbohydrates and so on contained in them. As a result, it may be that fruits, vegetables, fish and lean meat suit our bodies better than sat fat products. Devouring dripping hamburgers only feels good because animal fat was a scarce commodity during prehistory and so we were programmed to prioritise it. But we don't need anything like the amount of animal fat we consume now, the theory goes. Although Enig and Fallon's defence of the reviled substance makes compelling reading and has a ring of truth, it may not be entirely responsible. Neal Barnard, doctor and author of Turning Off the Fat Cells and one of America's top advocates for better nutrition, describes their case as more worthy of contempt than a rethink. 'Saturated fats are clearly linked to heart disease,' he says. 'Butter is loaded with it, and is every bit as bad as cardiologists have said it is. 'While soy oil and olive oil are as high in calories as any other fat, butter is just as calorie-dense. The notion that butter - or saturated fat in general - facilitates weight loss is absurd. The thinnest people on the planet - Asians and vegetarians - typically avoid butter and build their diets on staple foods from plants.' Possibly, the solution is to play it both ways. That is, eat a diet containing animal and vegetable fat equally in a spirit of variation.