It is difficult to envisage how we have become so confused about fats and whether saturated, or monosaturated, or polyunsaturated fats make good or bad foodstuffs. Moreover it is a puzzle as to whether a good diet should have 10% fat or 40% overall fat content. Shops are still selling foods on the basis that they are ‘fat reduced’. Crisp packets declare their 34-5% fat content from sunflower oil on the back of the pack, but oven-ready chips declare – on the front of the pack – ‘no more than’ 5% fat.
In India, many of the crisps are now cooked in palm oil and this is declared on the packet. If I say that I believe that palm oil is a better choice nutritionally, I will have many angry voices to answer. This is partly because many people still think that the higher level of saturated fat in palm oil is bad for health and partly because oil palms have been planted on a scale that has destroyed native forests and their wildlife, including great apes.
How do I answer the above? Well, first of all, there is now a groundswell acceptance that saturated fats are a healthy option as part of a balanced diet – and they are certainly more stable at higher cooking temperatures. Secondly, I suppose it is possible to plant oil palms in a less eco-destructive way and to process the harvest more sensitively. I believe the really big issue is summed up in this question: If saturated fats are good for health, why have they been associated with vascular and cardiac disease in so many studies? In other words, why did we become so frightened of saturated fats in the first place?
There are several factors that may have combined to make us feel that there was an issue with saturated fats. Historically it was the pronouncements of Ancel Keys around 1950 that established the idea in medical circles that saturated fats were bad for health. The cessation of whaling led to a search for replacements for whale oil, but the hydrogenation of vegetable oils provided an alternative raw material for food manufacturers and the margarine industry. This newly concocted source of hardened fats arrived at a time when a greater percentage of people had been nurtured on formula milk as babies. The combination of arterial disease resulting from bottle-feeding, and the consumption of foods rich in trans-fats, resulted in a wave of deaths from heart failure among the middle-aged. Once again, there has been an unfortunate barrier between the science of biochemical nutrition and the immunological approach to foodstuffs. Saturated fats became linked with arterial disease through the writings of Ancel Keys despite much contrary evidence. It now appears to me that infant nurture, corrupted by formula milks, was the principal cause of cardiovascular disease. Hydrogenated oils, rich in trans-fats, helped to convince medical researchers to believe that natural saturated fats were bad for health, when the key issue was not that they were saturated fats, but that a high percentage of saturated fats in the diet were likely to be from bovine sources to which an immune reaction had developed, postnatally, in infants that were bottle-fed.
With infants that are bottle-fed from birth, it is foods of bovine origin that are the most likely to cause arterial disease and heart attacks in later life. Whether the food is mostly fat or protein is of little consequence, if it comes from cattle it is likely to cause atopic illness of one kind or another, including blood vascular diseases. Once again, the replacement of genuine scientific study by pronouncements from figures of authority has corrupted medical practice and misled the media and consumers toward less healthy options.
It is probably best that we eat a wide range of naturally oily foods, whether from plant or animal sources, and that we take account of our own nurture as infants when choosing the source of any foods that we may eat.
Human populations have subsisted on a range of dietary options, from a high percentage of fat and protein and very little carbohydrate, eaten by those living in the extreme North, to a more vegetable and fruit based diet with some added meat or animal fat and protein, among those living nearer to the Equator.