The evidence is that the average response of the blood (LDL or total) cholesterol concentration to an increased fat intake (in the absence of a high carbohydrate diet), measured in thousands of patients, is no change. Yet we know that values do go up in some subjects. So, in an equal number of patients, the value must go down, which most people would consider to be good. So how can an “unhealthy” diet produce changes that are either very unhealthy or very healthy? It does not make immediate sense, so we need to dig a bit deeper.
There are 2 models for how heart disease develops – the cholesterol theory and the insulin theory. The cholesterol theory holds that cholesterol in the blood rises when one eats a high fat diet and this clogs the arteries causing heart attack. The treatment is therefore simple – remove all fat from the diet.
According to this theory, the only factors in your blood which you need to worry about are either your total or your LDL-cholesterol concentrations – anything that makes either one go up is bad, and anything that causes either to go down is good. Statin drugs reduce both and are therefore good, as is a low fat diet. The only trouble is that even the most religiously followed low fat diet will drop the total cholesterol by a homeopathic amount (about 0,2 mmol/L), which would be too little to make any difference even if cholesterol was the true cause of arterial “clogging”.
The insulin theory holds the opposite – that it is the consistently elevated blood insulin levels, caused by carbohydrate in the diet, that produce the series of conditions we recognise as Metabolic Syndrome (MS), which in turn causes heart disease. Individuals with insulin resistance (IR) are at an especially high risk, and are likely to develop MS when following a high carbohydrate diet.
The cholesterol theory of heart disease has never been proven. The best evidence that the science behind this theory is “junk” can be found in Nina Teicholtz’s new book, The Big Fat Surprise. It seems that we have been seriously misled by bad scientists, industry, and politics to accept a theory for which there is no good evidence. Then there is an entire $40 million per year industry – the cholesterol lowering (statin) industry – that seeks to ensure that we continue to accept this unproven theory without question.