The belief that saturated fat is a killer is outdated

stabilisers, emulsifiers, and more. My book, Swallow This, investigated these food-like constructions and explains why they are the main driver of obesity globally. Government diet advice should be unflinching here. You want to stay slim and fit? Then avoid ultraprocessed food.

If you just eat real food in natural forms it’s quite hard to overeat.

Very few of us could eat more than one apple at a go, but many could gulp down a large glass of apple juice, which is effectively sugar with all the fibre removed, in a flash. Real food sates your appetite. Ultra-processed has dissatisfaction built in; it leaves you craving more.

Calorie counting is a distraction. What matters is the nutritional quality of those calories.

Puffed rice crackers, for instance, are low calorie, eggs are much higher, but in terms of nutrient density and satiety, no prizes for guessing which is the more health-promoting food.

The high fat, sugar, salt obsession presents multiple fatal errors. On fat, it fails because it cleaves to the outdated belief that saturated fat is a killer. Systematic reviews and meta-analyses of randomised controlled trials put a lie to this. But the industrial, ultra-processed, polyunsaturated fats – “vegetable oil”, spreads, et al – the type we’ve been told are better for us, are doing us harm.

There’s no argument about sugar. The less we have, the better. But diet guidelines tell us to base our meals on starchy foods, which raise our blood sugar levels just as surely as straight sugar.

Salt is demonised because it can raise blood pressure, yet there’s no sound science to show that normal seasoning with salt in home cooking is anything other than tasty.