Low-fat diets and exercise are pointless for those wanting to lose weight and obese people should simply eat less, a leading surgeon has said.
Lord McColl, emeritus professor of surgery at Guys Hospital in London and former shadow health secretary, warned that current health advice to avoid fat was "false and misleading" and was fuelling the obesity epidemic.
Speaking at a House of Lords debate, the former surgeon warned that exercising was useless against the huge levels of calories from carbohydrates and sugars that people are now consuming. He warned that the obesity epidemic was as bad for public health as the 1919 flu epidemic.
"In the UK the Department of Health and Nice (National Institute for Health and Care Excellence) maintained for many years that the obesity epidemic was due to lack of exercise," he told peers. "It's a pity that the 500 people employed by Nice didn't think to go into the gymnasium get on a machine and exercise to see how few calories you actually burn off.
"One can peddle away on one of those machines for half an hour and only two or three hundred calories are burned up. One has to run miles to take a pound of fat off.
"The whole subject has been bedevilled by all sorts of theories about the cause of the obesity; genetics, epigenetics, psychological disturbances.None of them is the cause of the obesity epidemic. One fact remains. It is impossible to be obese unless one is eating too many calories."
In May the National Obesity Forum and the Public Health Collaboration called for a major overhaul of dietary guidelines, saying 30 years of urging people to adopt low-fat diets was having "disastrous health consequences" Their report claimed the low-fat and low-cholesterol message, which has been official policy in the UK since 1983, was based on "flawed science" and had resulted in an increased consumption of junk food and carbohydrates.
Lord McColl said eating fat was important as it kept people feeling fuller for longer. He advised overweight people to start adding fat into their diet.
"Fat enters the small intestine and greatly delays the emptying of the stomach," he told peers. "As the stomach emptying is delayed it gives the feeling that one has had enough to eat. Later when the fat has been absorbed the stomach then starts to empty again, It's a beautifully balanced mechanism which tends to prevent us from eating too much and prevents us from getting obese."
Researchers at Imperial College recently found that Britons are on course to be the fattest in Europe within a decade, with almost four in 10 people predicted to be dangerously overweight by 2025.