Many Medical Experts Are Certain They know What a Healthy Diet Is.

The wrong ideas of Ancel Keys, were widely accepted because they seemed to agree with good common sense. One gram of fat contains 9 calories and one gram of carbohydrate contains 4 calories. Surely it's obvious that eating high density fat, causes people to be fat. That sounds like science, but it has zero relationship to human biochemistry, and the way fats and carbohydrates are metabolised in the body.

Prof. Richard Feinman

In the 1970's there was very little real dietary science. Dietician's were not scientifically trained. (They are still not scientifically trained for the most part.) Anyone trained in biochemistry was in high demand in many industries, so almost nobody with that degree of training, took any notice of human nutrition. Biochemist Richard Feinman, taught human metabolism to medical students for many years. Late in his career (2000), he was asked to prepare some lectures as part of a standard course in human nutrition. It was then that he discovered the non-science, that passed for nutritional knowledge. He was shocked that such faulty material still existed in the university system, and was being taught to medical students, nurses and dietician's.

In the previous blog I referred you to the Women's Health Initiative (1991). Today we might look at the Multiple Risk Factor Intervention Trial. MrFit (Pronounced Mr. Fit). The director of the study, Jeremiah Stamler, a heart disease specialist, and associate of Ancel Keys was confident of success. This was an early sign that "Everyone knows what a healthy diet is," might not be as simple as everyone expects. The trial began in 1973, and from a group of 361,000 middle aged men, they chose 12,000, who were high risk for future for heart disease. They formed a control group, and a multiple intervention group.

There were FOUR things they strongly encouraged the men in the multiple intervention group to do. These four things are still part of what "everyone knows." Stop smoking, take blood pressure medication if needed, eat a low-cholesterol diet, and eat a low-fat diet. So the "healthy diet" emphasised eating lots of vegetables, drinking skim milk, eating margarine, only two eggs a week, avoiding meat and cutting out deserts. The control group could do what they liked.

If you ask people what a healthy diet is, most people today would still consider that the diet these men ate was healthy. As I keep saying we all have a lot of faulty dietary ideas, and our wrong ideas get us into trouble. There is an essay about the history of wrong dietary ideas here.

The men in the intervention group were quite successful in making lifestyle changes. The intervention group did have lower rates of total cholesterol, yet the men in the intervention group died at a higher rate than those in the control group. The trial was stopped. This FAILURE was embarrassing and the result was set aside, because it wasn't understandable. Clearly they did not know what caused heart disease. Years later Dr Stamler was asked what went wrong. He replied honestly; "I don't know."

This was fairly clear evidence away back in 1982, that total cholesterol is not the villain that causes heart disease. Last year, 2015, cholesterol was officially taken off the list of dietary concerns. There are two reasons. You can't control serum cholesterol by dietary methods. HDL-C is proven beneficial and LDL-C is not shown to be harmful, although a question remains about small dense particles in LDL-C. That raises a serious question about taking statins, but I don't know enough about that to comment.

MrFit was also a weak pointer, to suggest that the low fat diet, might not the as "healthy" as everyone was thinking either. Today, forty-three years on, we can see that the low fat diet begins to cause problems in older people. The evidence for that is all about us. Scientifically that was best demonstrated by the Women's Health Initiative Dietary Study, 1991-1998, and reported as "having no health benefits" in 2006.

John Stephen Veitch