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Love your food but don’t eat quite as much of it as you want

Dr Giles Yeo arrives for lunch in Cambridge by bike from his research lab at Addenbrooke’s Hospital. In a corner of the Oak bistro he exchanges his clip-clop cycling shoes for a pair of sandals, hangs his fluorescent jacket on a peg, and explains to me the heart monitor that – if he keeps it above a certain daily level – saves him £250 a year on his life insurance. “Their goal and my goal are aligned – neither of us wants them to pay out…” Yeo, 45, is the scientific director of a group studying the effects of genetics on food intake and a pioneer in studies of the cause of obesity. He is, grinning at the prospect of lunch, a somewhat daunting picture of health.

I’m eager to see what he is going to order. His well-timed new book, Gene Eating, debunks much of what we might have taken as read about diet and dieting. It presents the evidence to show that any kind of one-size-fits-all regime is likely to be of little value. He has a gift for describing the science of how our bodies take in calories at different rates and respond radically differently to food groups. Calorie-counting ignores the fundamentals of calorie absorption, and is at best a very rough guide. Much of the trick is to find what works for you.

He scans the menu, aware that I am observing his choices. “I am going for the calves’ liver, because I rarely eat it, and I imagine they do it well here,” he says. “And I will have the lobster bisque to start. I love a bisque.” Are we allowed a glass of wine in the middle of the day, he wonders. He decides we are, and orders a large glass of malbec.

Yeo was born in Singapore and grew up in San Francisco. When he came to Cambridge as a postgraduate, he found the food options “a bit embarrassing”. It’s got better now, he says, not least since this place, a confident neighbourhood French restaurant, opened a decade ago. Still he has been unable to find any decent Chinese food in the city – he has to go to London for that.

When Yeo got into the study of obesity, it wasn’t yet a global growth industry. He started by looking at people with rare genetic disorders, “Kids who literally could not stop eating,” he says – he describes in his book the children who have no off switch to their appetite, and will eat fish fingers from the freezer if left alone.

As he and his fellow researchers began to understand more about how the brain failed to control food intake in extreme cases, they started to see how the disruption of those regular pathways was not unique to severely obese people. There was a spectrum. Yeo left pure genetics and became an accidental neuroscientist. His principal interest is now the genetics of how the brain controls food intake.