Obesity: Low-fat Diet

Lord McColl of Dulwich Excerpts

Thursday 9th June 2016 Lords Chamber

[Lord McColl of Dulwich (Con)]

My Lords, I am grateful to my noble friend Lady Jenkin of Kennington for initiating this debate, which draws attention to the false and misleading advice that a low-fat diet is the way to tackle the obesity epidemic—an epidemic which is killing millions, costing billions and to which the cure is free. You just have to eat fewer calories.

I remind your Lordships that when we swallow food it goes down through the gullet into the stomach, in the upper part of the abdomen. The advice to have a low-fat diet is wrong because, when fat enters the small intestine, it meets special receptors that detect differences in the composition of food. This information is transferred to the stomach and results in delay of emptying. Fat is especially important because, when it enters the small intestine, it greatly delays the emptying of the stomach by making the upper part of the stomach relax and the lower half less active. As the stomach emptying is delayed, it gives the feeling that one has had enough to eat. Later, when the fat has been absorbed lower down, the stomach then starts to empty again.

This is a beautifully balanced mechanism, which tends to prevent us eating too much and thereby prevents obesity. Not surprisingly, the food industry does not approve of this beautifully balanced mechanism, because it has resulted in less food being eaten and lower profits. So it joined up with some rather dubious scientists to produce research that erroneously claimed to show that fat was bad and carbohydrates were good. They ignored the fact that, when carbo- hydrates and sugar enter the stomach, there is very little delay, and the food quickly rushes on. There is no feeling of having had a full meal; the person soon feels hungry and starts to eat again—and they continue to eat too much throughout the day. This has led to obesity in a large proportion of the people in the UK and an even larger proportion of people in the United States.

Recently, there has been a lot of interest in the composition of food, especially in the fact that fat plays a valuable part in weight control. These statements are recent but not new; many of us clinicians have been teaching this for many years, because of the work of Professor Yudkin in the 1960s, and his book published in 1972. However, his message that the answer was fat, not carbohydrates, and that carbohydrates were the danger was not popular with some parts of the food industry, and his career was actually rubbished by unscrupulous scientists in cahoots with even more unscrupulous parts of the food industry. It was a disgrace. The campaign to extol the virtues of a high-carbohydrate, high-sugar diet was started largely in the United States, where it was decided by scientists and food manufacturers that the increasing amount of coronary artery disease was due to excessive fat in the diet. Fat was demonised; a high-carbohydrate, sugary diet was broadcast as the answer; and anyone who contradicted that was marginalised. It has been pointed out that a low-fat diet is not very tasty and it is thought that for this reason the food industry started putting a lot of sugar into food to compensate and make it more palatable, so boosting their sales. The food industry seems to regard money as more important than many parts of the health of the people.

In the United Kingdom, as many noble Lords know well, the Department of Health and NICE maintained for many years that the obesity epidemic was due to lack of exercise. It is a pity that some of the 500 people employed by NICE did not think to go to the gymnasium, get on a machine and exercise to see how few calories one actually burns off. One can pedal away on one of those machines for half an hour and only 200 or 300 calories will be burned up. One has to run miles to take a pound of fat off.

This whole subject has been bedevilled by all sorts of theories about the cause of the obesity epidemic: genetics, epigenetics, psychological disturbances and many other ideas. They are all very interesting, but none of them is the cause of the obesity epidemic. They may contribute to making it more difficult for some people to control their appetite, but one fact remains: it is impossible to be obese unless one is eating too many calories. Only a quarter of the calories we eat are actually expended on exercise. The remaining calories are burned up enabling the heart to beat 8 billion times in a lifetime, the kidneys to filter gallons of blood every day, and numerous chemical reactions in the liver, pancreas and so on.

We have been advised not to be judgmental and not to blame patients for being obese. We are not even allowed to call them fat nowadays, but it is not judgmental to be accurate in diagnosis. It is not for government to tell people how to run their lives, but it is the job of government to give a very clear picture of the truth. I hope that when the obesity strategy is eventually published it will have on the front cover: “Obesity is killing millions, costing billions and the cure is to eat less”.

In a recent review, Dr Aseem Malhotra, a cardiologist, concluded that the current global epidemic of atherosclerosis, heart disease, diabetes and obesity is being driven by a diet high in carbohydrates and sugar, as opposed to fat.

How can we help obese people to avoid an unnecessarily early death from the effects of obesity? It would help them to have a reasonable but not excessive amount of fat, which would satisfy their hunger early on in their meals, and to avoid a diet high in carbohydrate and sugar, which would continue to make them hungry. Roughage in many forms, such as wholemeal bread, wholemeal pasta—pasta integrale—and cereals without sugar also satisfy hunger quickly. It is essential to avoid high-carbohydrate and sugar diets which will continue to make them hungry. Many will need additional help from friends, dieticians and psychiatrists—all this to avoid so many unpleasant illnesses and to avoid them falling victim to this lethal obesity epidemic, which is the worst since the flu epidemic of 1919.