Fats: An Inaccurate Hypothesis

Consequences still felt today
Dietary guidelines from experts and governments have been largely based on Keys’ work. To lower our intake in cholesterol and saturated fats, populations have massively consumed food products in which the industry had replaced fats with carbohydrates, and had replaced saturated fats with vegetable oils rich in Omega-6.

This did not change the prevalence of atheroma-related diseases. New research even shows these changes may be linked to the obesity epidemic and type-2 diabetes.

Palm oil for one, which has a good balance between saturated and unsaturated fats, constitutes a healthy alternative – but it has been unjustly maligned for containing saturated fats.

There have been economic consequences, too. These are linked to the ability of the industry to have quickly found a new market opportunity with low-fat food products. It has, as always, shown to be very innovative in that regard. Its lobby was powerful and ‘low-fat’ developed globally, even though it is not possible as yet to show it has had any positive impact on cardiovascular health.

In the 40 years between Keys’ work and the shadow cast upon it, many scientific articles have been published to try and explain the anomalies observed in real populations. None ever questioned what had become a dogma. The different paradoxes, including the famous French Paradox, have only started to shake the foundation of his hypothesis.

Who bears the responsibility?

Surely, Keys cannot be held responsible for how his data was used. But his vision clearly influenced medicine for generations and over-stated the importance of saturated fats and cholesterol in cardiovascular risk.

Exegetes of Keys at the University of Minnesota wrote about the Seven Countries Study:

“The main implications of the Seven Countries Study are that the mass burden and epidemic of atherosclerotic diseases has cultural origins, is preventable, can change rapidly, and is strongly influenced by the fatty composition of the habitual diet. The study implies the universal susceptibility of humans to CVD but that the frequency of susceptible phenotypes is greatly reduced in favourable environments. It suggests there may be other and important protective elements in the diet and lifestyles of Crete and Japan.”

The only concession made to Keys’ theories is the confirmation of a strong influence of the composition of lipids in the diet, but the words ‘saturated fats’ are no longer used.

In the Journal of the American College of Cardiology, Vera Bitter recently reminded physicians:

“Atherosclerosis is a multifactorial disease and requires a multifactorial approach with smoking cessation, dietary modification and weight management, regular physical activity, attention to psychosocial risk factors, and pharmacological therapy of lipid and nonlipid risk factors. Comprehensive risk factor control is associated with improved prognosis, and our challenge is to develop care models that will allow us to achieve such control.”

We need to keep in mind that tobacco, type-2 diabetes and hypertension are, in that order, more powerful atheroma risk factors than LDL particles. There is no interest in dietary cholesterol in preventing CVD. Saturated fats, like monounsaturated fats, and like carbohydrates increase the amount of LDL particles when in calorie excess and promotes atheroma if other risk factors are present, and if phenotype is susceptible.

This is the reason why we cannot predict among high-LDL patients those who will have a cardiovascular, cerebral or peripheral event, other than watching the three aforementioned powerful risk factors, or having proper atheroma plaques examinations.

In summary, Keys was wrong, and his mistake has been compounded over the decades. It is time now to end the crusade against saturated fats.

Dr Guy-André Pelouze
Cardio-thoracic Surgeon,
France

This article contains extracts from the scientific paper ‘Ancel Keys: Science is not believing’.