The alleged benefits of drinking lots of water are a con invented by the bottled water industry. Eating unpasteurised cheese is incredibly unlikely to cause any problems during pregnancy. Locally produced food is not always better for the planet. Cutting salt out of your diet is more likely to do harm than good. Furthermore, supplements are a waste of money.

By Tim Spector's own admission, almost every opinion about eating healthily that he held a decade ago has turned out to be a dud. In his new myth-busting book Spoon-Fed: Why Almost Everything We've Been Told About Food is Wrong, the professor of geneticsA branch of science that studies genes. Genetics can include looking at how some diseases are passed down the generations, like cancer or heart problems. challenges much of the received wisdomInformation that most people generally believe to be true, although it might not necessarily be. we have come to believe about healthy eating.

The overall thesis of the book is that it is fine to eat most food types in moderation, and not stress about it. But we should certainly consume more plants - and less meat and fish - and vary our diet more

He is a particular proponent of taking care of our gut, where trillions of friendly microbes can be helped by a regular intake of fermented foods such as yoghurt.

Spector believes it is the "industrialisation" of food - the mass consumption of heavily processed snacks and meals - that is behind that particular curse of the modern age, widespread obesity and all the health problems that come with it, particularly diabetes.

He would far rather you sat down with a juicy steak from a good farmers' market than with anything that comes in a packet from a factory.

The food industry is one of his targets. The ten biggest food companies control 80 % of store-bought products globally, and their combined profits were more than $100 billion in 2018. Little wonder they are keen to spend their money on research that doesn't affect their sales.

Calories are another false friend in our fight against obesity, Spector argues. The system of measuring the calorific units in different foods by establishing how much heat they give when burnt was developed in the 18th and 19th centuries, but little has been added to the science since.

World Health Organization guidelines suggest men eat 2,500 calories a day and women 2,000, but widely varying metabolic rates render these figures useless.

Furthermore, he says, we are now gaining a better understanding of how foods interact. The calorie content of almonds, for example, has been inflated by 31% because we didn't realise that much of the fat they contain is not released when we eat them.

Likewise, no one would suggest that a corn on the cob has the same nutritional value as a bowl of processed corn flakes, yet the calorie count is the same. To use such a simplistic measure as your guide when pulling ready meals off a shelf is clearly nonsense.

Yes, say some. Food and nutrition is a much more complex subject than we've been led to believe. As a result, lots of the certainties we have about food are often oversimplifications or simply wrong. Food is also a very emotiveSomething that has the power to arouse intense feeling or emotion in somebody. subject, and we would understand our eating habits better if we put it in the context of our mental health.

No, say others. Spector himself doesn't really believe his own title. As the Times review says: "This is not a book for those seeking definitive answers; the subtitle might better read not as Why Almost Everything We've Been Told About Food Is Wrong but Why Almost Everything We've Been Told About Food Is Not Necessarily Right."