This week, columnist Ruth Wishart, who is chairing several panels at the Edinburgh International Book festival, describes one such event with geneticist and TV presenter Giles Yeo.

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This man. This man I have only just met. This man has just uttered the words every woman wants to hear: “Eating too much might not be your own fault.”

Well, what Giles Yeo, geneticist and TV guru, actually says in his new book is this: “The drive to consume food is one of the more primitive instincts to promote survival.

“It has been shaped by many millions of years of evolution.

“Thus I would argue that to be overweight in our current environment is indeed the natural – highly evolved even – response.”

There ya go. I’m not more amply proportioned than I would like, merely highly evolved!

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Dr Yeo has spent several decades examining the obesity business, after which he feels able to say, without any hesitation, that anyone selling you a diet and claiming it will make you slim and gorgeous is lying in their teeth (whilst pocketing your cash).

You can’t get around the basic physics, he reminds you. Too much food with too little exercise equals too many inches.

What makes his diagnosis different from most, though, is that the need for food, and the amount you consume, will be down to your genetic make up.

Which brings us to comforting thought number two. “Not eating when you are not hungry is easy. Thin people are not morally superior with the willpower of forged steel.

“They just feel less hungry so get full up more easily.

“It requires no effort.”

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But he concedes that losing weight and keeping up the loss is a bit of a slog. Though he has a lot of useful things to say about which foods will help you along the way by taking longer to digest.

And he’s fascinating too on how, in terms of what we eat and when, we’ve upended the traditional pattern of our pre-urban ancestors.

According to Giles, a healthy pattern is a very decent breakfast, a reasonably modest lunch, and a very light supper.

So tucking into a mound of moussaka, as I did the night before typing these thoughts, is not really all that smart. (Tasty though!)

Dr Yeo is also very funny on the subject of gym bunnies and their typical lifestyle.

“Is it not a weird thing,” he observes, “for a significant chunk of the population to drive to a gym, maybe take an escalator or elevator up or down a couple of floors, only to get on a treadmill, or a stationary bike?”

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Frankly, if the good Dr Yeo was not a very happily married man, I’d have insisted he migrate to Scotland.

Though it should be said that he is a very dapper, slimline sort of chap.

Not all that highly evolved really.