Peter Österberg, Ph.D.

Nobody profits from telling you the body heals itself. So nobody tells you. Your taste buds are new every 10 to 14 days. The tongue reading this flavour is a fortnight old. Your stomach lining rebuilds every 3 to 5 days. Last week's gut is already gone. Your skin turns over every 4 weeks. You grew a whole new surface this month. Your white blood cells renew in days. Tonight's immune army was not on watch last week. Your red blood cells retire every 120 days. Four months, and the entire fleet is replaced. The fat built into your cell membranes turns over too. Years of stored seed oil can slowly be walked back out. Your liver just gets on with regenerating. It holds no grudge about the bad years. Your skeleton rebuilds over roughly ten years. The bones made in the worst years are not the ones you finish with. Every one of those rebuilds is made from what you feed it. Feed it meat, fat, sunlight and sleep, and it builds you strong. Feed it sugar, seed oil and the sofa, and it builds you soft. The body you will have next year is under construction right now. What you give it today is what it builds you into.

The fear around bacon and the other processed meats is one of the great triumphs of bad science. Here's how the trick works. In the studies, processed meat rarely travels alone. It shows up alongside the white bun, the hash browns, the sugary drink, the crisps, the cigarette, the whole slovenly lifestyle. Then the meat gets handed the bill for the entire party. And the nitrates everyone's so frightened of? Around 80% of the nitrate you eat comes from vegetables. Spinach, rocket and beetroot carry many times more than a rasher of bacon ever could. If nitrates really scared you, you'd be far more frightened of the salad than the fry-up. Better still, stop swallowing your own spit. Your body actively concentrates nitrate in your saliva and drips it down your throat all day long. You produce more of the stuff yourself than the butcher ever added. Bacon's whole crime was keeping bad company at breakfast.

In 1967 India ran one of the most inconvenient heart studies of the century, almost by accident, and the field has been quietly looking away from it ever since. Dr S.L. Malhotra had a researcher's dream sitting in front of him: the Indian railway workforce, well over a million people. Same employer. Same medical cover. Comparable pay and hours. Scattered the length of a subcontinent. Strip all of that out and one great variable remained. Diet, which in India meant geography. In the north, in Punjab and Rajasthan and UP, the railwaymen ate the way their grandparents had. Ghee. Milk fat. Curd. As much as nineteen times more fat than their southern colleagues, and nearly all of it the saturated animal fat that Ancel Keys was at that very moment teaching the West to dread. In the south the plate was rice, sambar, and seed oils, groundnut and sesame, with far less fat overall. By the brand-new rules being drafted in America, the southerners were the ones doing everything right. Then Malhotra counted the bodies. Heart disease deaths in the south: 135 per hundred thousand. In the ghee-soaked north: 20. Seven times the disease in the men eating the wholesome seed oils. Among the railway sweepers, the leanest and hardest-working of the lot, the gap yawned open to fifteenfold. He chased down every other explanation within reach. Smoking ran the wrong way, the north smoked more. Activity gave no clean signal. Wealth made things worse if anything, executives dropping dead while the sweepers carried on. The one thing that tracked the dying was the fat in the pan. It was published. Peer-reviewed. British Heart Journal, 1967. It landed in the exact decade the West was pouring concrete around the opposite belief. Heart associations were prescribing vegetable oils. Factories were tooling up to turn them out by the tanker. A study showing the seed-oil eaters dying seven times faster was not a study anyone with a budget wished to repeat. So nobody did. Almost sixty years on, the finding still stands, unrefuted and unloved. It has never once troubled a dietary guideline.

The funniest maths in modern environmentalism. One almond requires 12 litres of irrigated water to produce. Peer-reviewed, ScienceDirect, 2017. A glass of almond milk contains roughly 50 of them. 600 litres of water before the carton is filled. The water comes from the San Joaquin Valley in California, which sits over one of the most over-extracted aquifers on earth. The valley floor has subsided by up to nine metres in places due to groundwater depletion. The carton is then refrigerated, sailed across the Atlantic, refrigerated again, lorried to a Manchester Tesco, and bought by someone who is concerned about the environmental impact of dairy. Meanwhile, in Cheshire. A British dairy cow drinks roughly 70 to 100 litres of water a day and produces around 28 litres of milk. That's about 3.5 litres of water per litre of milk. The water is rainwater that fell on her field or came from a local stream fed by the same rainwater. The rain was going to fall on the field whether the cow stood in it or not. 80% of her moisture intake comes from the grass itself, which is also rain. She converts the grass, free of charge, into a litre of milk containing seven times the protein and four times the calcium of almond milk, and shipped roughly 18 miles to the same Tesco. To recap. 600 litres of stolen aquifer, flown halfway round the world for nutritionally worthless beige water. Or 3.5 litres of rain that was already falling, converted by an animal you can pet, into actual food. The shopper picks the almond. She has been told this is the ethical position. The aquifer would like a word.

Vitamin D is not really a vitamin. It is a steroid hormone. Your body manufactures it from cholesterol when UVB strikes your skin, sends it to the liver for one conversion, sends it to the kidneys for another, and from there the active form goes on to regulate over a thousand genes. Bone health. Immune function. Mood. Insulin sensitivity. Cardiovascular function. Cancer risk. Fertility. Cognition. The dose is the sun. The factory is your skin. The raw material is cholesterol, which we have also been told to be afraid of. So look at what has actually happened. You have been told to avoid the sun. You have been told to lower the cholesterol your body uses as the precursor. You have been told that animal fat, the natural dietary source of the finished hormone, is what's killing you. And then, when the inevitable deficiency arrives at your annual blood test, you have been prescribed a small synthetic pill to replace the hormone the system was designed to make for free. Three of the inputs your body requires were removed. The output collapsed. The output is now sold back to you in capsule form. The system was not broken before we started fixing it. We were.

Margarine was the great winner of the low-fat era. It is worth being honest about what it actually was, and what it still is. The cheapest vegetable oil on the planet, beaten with hydrogen gas under pressure until it stopped behaving like oil and started behaving like a solid. The reaction produced trans fats. Molecules so structurally wrong the human body cannot metabolise them. Molecules that lodge in cell membranes where the fat that built you used to sit, drive inflammation, and raise the exact cardiovascular risk margarine was being sold to prevent. Trans fats are now banned or restricted across most of the developed world because they were, conservatively, killing tens of thousands of people a year. This is what an entire generation of mothers was told to spread on their children's toast instead of butter. Butter, which is cream that has been shaken, eaten by humans for somewhere between four and ten thousand years. Margarine, an industrial product invented in 1869 to feed Napoleon III's army on the cheap, reformulated repeatedly as each version was quietly found to be more harmful than the last, and marketed each time as the heart-healthy choice. The adverts showed sunflowers. The tubs were yellow. The names suggested a farmhouse. The product inside was an industrial fat the human body had no machinery to process, sold against the real food it had been brought in to replace, in the name of preventing the disease it was actively causing. And here is the part nobody mentions. The trans fats were quietly removed in the 2000s. The new version is a blend of rapeseed, palm, and sunflower oils, processed with hexane solvent, deodorised, bleached, and emulsified into a tub. Still industrial. Still seed oil. Still nothing the human kitchen had until a hundred years ago. It still sits on the shelf next to the butter. Still in the same yellow tub. Still marketed as the heart-healthy choice. The little symbol on the lid still tells you a charity has approved it. The butter was never the problem. The thing they told you to replace it with was the problem then, and a reformulated version of the same thing is the problem now. The cow was right. The factory was wrong. It is still wrong. They just changed the wording on the side of the tub.

Butter improves everything it touches. Swap the seed oil in your frying pan for butter and the eggs become a different food. Swap the margarine on your toast for butter and the toast becomes a meal. Swap the vegetable oil in your roasting tin for butter and the potatoes acquire a crust that has previously only been described in religious texts. Swap the spread on your sandwich for butter and the sandwich stops being sad. Swap the oil in your pasta water for a knob of butter at the end and the pasta tastes of something for the first time in your adult life. Swap the cream in your scrambled eggs for butter and the eggs go silken. Swap the mayonnaise on your steak sandwich for butter and the steak sandwich becomes the only sandwich that matters. Swap the olive oil on your roasted vegetables for butter and discover that vegetables were waiting for this their whole lives. Swap the lubricant on your bicycle chain for butter and the bicycle still works, briefly, and smells faintly of breakfast. Swap the moisturiser on your hands for butter and your hands are softer, although your colleagues will have questions. Swap the petroleum jelly on a stuck zip for butter and the zip moves. Swap the WD-40 on a squeaky hinge for butter and the hinge goes quiet for approximately a fortnight. Swap the polish on your leather boots for butter and the boots are conditioned, fed, and faintly delicious. Swap the wax on your surfboard for butter and you will fall off, but you will fall off into a sea that briefly tastes of a French bistro. Swap the candle in your candelabra for a stick of butter with a wick pushed through it, which is, incidentally, what the Tibetan monasteries have been doing for a thousand years, and discover that yak butter lamps are not a metaphor, they are an HVAC solution. Swap the diplomatic gift you were planning to bring to a foreign head of state for a wheel of properly aged farmhouse butter and watch the negotiations soften considerably. Swap your morning coffee creamer for a tablespoon of butter blended into black coffee and notice that you do not become hungry until 2pm. Swap your protein shake post-workout for a ribeye cooked in butter and notice that your recovery improves and your kitchen smells better. Swap your evening glass of wine for a small dish of cultured butter and a spoon, and accept that you have crossed a threshold most people will not cross, but the people on the other side of it look extremely well. Butter has long since stopped being a fat. It is now a strategy.