Burn more calories than you consume to get rid of that big fat problem

With 30,000 dieting books worldwide and a multibillion dollar dieting industry underpinning them, you would have thought we have obesity under control. On the contrary, the obesity crisis is running rampant, and nowhere worse than Hong Kong and China.

“We face an unprecedented epidemic of obesity and chronic ill-health, with no obvious end in sight,” says Tim Spector, Professor at Kings College London and author of The Diet Myth.

Susan Roberts, senior scientist at the Tuft University’s Energy Metabolism Laboratory at the Human Nutrition Research Centre on Ageing, is even more blunt – and specific: Obesity is “one of the greatest health challenges facing humanity.”

She says 600 million people – about 13 per cent of all adults – are obese. That’s double the number in 1980. And the crisis pays no regard to wealth or poverty. Mexico is the “world champion” for obesity levels, just ahead of the UK. And in Malaysia, approximately half of the population suffer from diabetes. In China and India, obesity levels have tripled in three decades.

While the US has for many decades held the dubious title of the world’s most overweight nation – and on current trends will see half the population overweight, or obese, by 2030 - that mantle as world leader has recently been wrenched from it.

Rising wealth, an explosion in fast food, and declining exercise, mean that China is now home to the world’s largest population of obese people – around 120 million – with around 600 million overweight.

That is perhaps why Beijing recently launched its Healthy China 2030 plan, because along with obesity goes a suite of unsavoury sources of sickness: heart disease, strokes, many cancers, and of course diabetes. China has an estimated 130 million diabetics – 30 per cent of the world’s total.

Despite the glaring obviousness of the crisis, Prof Spector complains of widespread medical neglect: “Obesity is still a massively neglected area of medicine, with little funding, no speciality training and no common voice with which to try to combat the billion-pound marketing budgets of the food companies.”

He complains of “a mass of competing religions” around dieting fads and snake oil solutions. The cynical role of the world’s leading food producers is taken as given.

Both Spector and Susan Roberts puzzle on the same conundrum: if, after all this time, so many diet “solutions” have failed to provide any solution, why do they still attract such massive followings?

For Prof Roberts, in a recent report in the Scientific American based on 20 years of research at Tufts, the solution is brutally simple: burn more calories than you consume.

So simple, so difficult:

• Exercise is less important than people think. Over a quarter of our calories are burned by our brain. Even sitting on the sofa watching TV consumes 60 calories an hour.

• Consume 100 more calories than you burn every day – the equivalent of two small biscuits – and you will add around 3kg in a year – that’s 30kg in a decade.

• Americans today consume an average of 500 more calories a day than they did in the 1970s.

• Peoples’ metabolisms vary, and they slow as we get older, so what is just right for one person can be responsible for significant weight gain in others.

• It is harder to get at, and extract, the calories in unprocessed, high fibre foods. Our bodies can extract around 4 calories per gramme of proteins and carbohydrates, but 9 calories per gramme from fats. Eat a gramme of raw almonds instead of the same weight of almond butter, and your body is only able to grab 70 per cent of the available calories. So “not all calories are equal”.

• Foods with a high “glycemic index” – which measures how fast the calories are absorbed by our bodies – leave us with irresistible food cravings more often than foods in which the calories are hard to extract.

Despite the rigour of Susan Roberts’ research at Tufts, Tim Spector believes she only captures half the story because she takes no account of our “microbiome” – those 100 trillion microbes that populate our gut and are responsible for most of the digestion.

Apparently, we all have very different balances of microbes inside us, and how well they work dictates how well we manage our weight – and our health.

Worryingly, compared with humans 15,000 years ago who fed an average 150 ingredients to their gut every week, we today feed on just 20 – and the majority come in the form of corn, soya, wheat and meat.

“Diversity is key,” Spector said. “A calorie may indeed be a calorie, but in the real world inside our intestines they are definitely not equal in the effects they have.”

Around the world today, it seems the best diet both for weight control and health is the Mediterranean diet – with lots of olive oil, nuts, vegetables, and of course, wine.

As a personal guide, I am still today strongly guided by Michael Pollan’s deceptively brief Food Rules. It is he who warned me that I should never eat food items that my grandmother would not recognise as food.

He also told us not to eat any food product that has more than five additive ingredients listed on the side of the pack. The only problem with this rule was that quickly after publication, many food companies trimmed their labelling back to five.

Pollan also offered me brilliant simple tricks: prepare the food yourself – because that way it takes longer to eat: use small plates; always put your knife and fork down between mouthfuls – that way you eat slower. But his overall food rule is the one I love best: “Eat food, mostly plants, not too much.” Follow that rule, and I think you can save thousands on quirky diet fads. And the world’s massive obesity crisis might gradually come under control.

David Dodwell researches and writes about global, regional and Hong Kong challenges from a Hong Kong point of view