I was hovering over the nuts display in the supermarket, wondering which to buy. I had just interviewed Oliver Selway, a radical diet-and-fitness coach and proponent of a food regimen that does not fear fats. He had told me macadamias were by far the most nutritious nuts to eat, a nut that any dieter will know is forbidden as it is astonishingly calorific. “They’re the fattiest nuts, you know,” a woman next to me said. “They are so bad.” Cheerily, I repeated Selway’s nutritional proposition: that animal and other natural saturated fats from whole foods are good for us. They are what human bodies have known for millions of years…….All natural fats have functions for health: they are not inherently bad…….margarine ‘the devil’s semen’……..told for decades to cut saturated fat from their diet, they replace have replaced it with what some studies suggest is more harmful: refined carbohydrates.