Fat, fat and more fat

I love fat. I was born 2½ years before the end of the Second World War, and I grew up during rationing. You didn’t waste food in those days - especially not high-energy food like fat. And at that time nobody realised just how harmful fat was. In our flat, only sissies cut the fat - or the gristle - off their meat. Tough guys like me and my Dad ate the lot. (Actually, I can vividly remember trying miserably to mash mouthfuls of gristle down to swallowable dimensions and having to excuse myself so I could spit them gratefully down the loo.)

So now I’m a fat addict. My favourite cheeses are full-fat ones, preferably with a creamy or buttery texture. I love butter on my bread, fat on my bacon, olive oil on my plate, cream on my puddings… I just love the stuff in all its luscious, lethal forms.

So it isn’t surprising that I was more interested than many of my friends to make two discoveries, some time apart.

First, there was the news that people who live on a diet rich in olive oil have a much lower incidence of heart disease than those whose fat intake is dominated by butter and other animal fats. It turned out that olive oil contains something called mono-unsaturated fats and that these are far better for you, cholesterol-wise, even than the poly-unsaturated fats in more boring oils like sunflower (I was never going to be weaned off butter by sunflower margarines anyway). These don’t just deposit less cholesterol on the walls of your blood vessels, it seems: it’s said that they actually patrol your cardio-vascular system and get rid of the evil stuff. Not only do I love olive oil - I love the whole southern European diet and cuisine that go with it and depend on it. So for me, this was momentous news.

Then, much more unexpectedly, came the news that people in the south-west of France, where the main dietary fats come from ducks and geese, have just as low an incidence of heart disease as people in the south-east, where the main source of fat is the olive. It seems that duck fat and goose fat also contain mono-unsaturated fats. As it happens, I’m also very partial to duck and goose products - particularly foie gras, which is produced from birds which have been deliberately fattened-up - so this was equally good news for me.

Truly, the inhabitants of the south enjoy many blessings. They have the weather, the surroundings, the food - and lots more time to enjoy them. Obviously I was born at the wrong latitude (except that, at 65, my first-ever cholesterol test showed me to be well within the ?normal? range).

The bad news, of course, is that when it comes to calories - and therefore to waistlines - a fat is a fat is a fat. Beef dripping, bacon fat, sunflower oil, olive oil, goose dripping, butter, cheese - the fats in all these foods deliver, gram for gram, the same number of calories and therefore the same number of centimetres on the waistline. In fact, while butter is 18% water, olive oil is 100% fat.

The experts who tell us how to live our lives (rather than how to enjoy them) bombard us with terms like saturated fats and polyunsaturates. The manufacturers of healthy-ish margarines pick the terms up and pepper their advertising with them to frighten us into eating their depressing products. But what do they actually mean?

To understand this, rather than just use it to keep healthy, you need to learn just a little bit of chemistry. It sounds daunting, but bear with me and have a go.

The major components of all fats are compounds called hydrocarbons which, unsurprisingly, are composed of hydrogen and carbon. If you haven’t done enough science to understand that a very light flammable gas used for lifting very dangerous airships off the ground and a powdery black solid used in pencil ’leads’ can combine to create a substance like petrol, you have a little problem - but don?t worry: I don?t understand it, either - I just take it on trust. But you must know that the same dangerous gas can combine with another gas, dear, friendly oxygen (without which we would die in seconds) to produce H₂O - good old water (without which we would die of dehydration in days). So just accept the hydrocarbon bit and read on!

So hydrocarbons are composed of hydrogen and carbon and fats are composed of hydrocarbons plus a few other chemical odds and ends.

A hydrocarbon can be either saturated or unsaturated. A carbon atom has enough ’hooks’ to link it to up to four other atoms, and in a saturated hydrocarbon molecule every carbon atom is bonded to two carbon atoms and two hydrogen atoms.

In an unsaturated hydrocarbon molecule there is a point where two carbon atoms are double-bonded - each is linked normally to one other carbon atom and one hydrogen atom, but they use both of their other links to bond to each other. In some way which Harold McGee in On Food and Cooking takes for granted and I don’t really understand, this creates a weakness in the molecule. Highly reactive atoms such as oxygen can come along and displace the one hydrogen atom that is bonded to one of the double-bonded carbon atoms. Then the hydrocarbon isn’t a hydrocarbon any more, and the fat containing that molecule becomes oxidised - rancid, in plain kitchen terms. So saturated fats keep better than unsaturated ones, but they have strong links with heart disease - probably because their hydrocarbons are harder for the body to break down and they therefore stay ’fatty’ longer.

A polyunsaturated hydrocarbon molecule has more than one double bond. A mono-unsaturated hydrocarbon has only one. A fat can contain a mixture of saturated, polyunsaturated and mono-unsaturated hydrocarbons...

All this explanation is tiring. I will return!