I first saw David, on a cold spring morning standing in the forecourt of the Ufizzi in Florence. Centuries of neglect and the carelessness of pigeons could not dim the radiance of Michaelangelo’s homage to manly beauty. David has since been cleaned up, and moved indoors into the Academica where he now gleams in pristine Renaissance marble.

David maybe the ideal but we are constantly reminded that there is a worldwide crisis with obesity. Ministries of health worldwide, University departments and the public are fixated on the coming epidemics, and how to provide for them.

Why is this happening? The simple equation is that if we consume more energy than we use, the excess becomes fat. We consume too much and expend too little. So the obvious solution is diet and exercise. While this is common sense and part of a solution, it does not explain the problem.

When humanoids descended from the trees, stood up, and looked around, what were they looking for? Food and predators. The gatherers in the trees had become the hunters of the plains. They had to evolve a set of attributes to survive. But to survive they had to hunt and kill, occupations that required energy expenditure. And when they ate they had to store a surplus until the next kill.

Ordinary cane sugar (table sugar) is sucrose, which contains glucose and fructose joined together in equal amounts. There are two main energy storage systems. Glycogen, which is stored in muscle and liver and comes mainly from glucose, after the digestion of carbohydrates (rice, pasta, bread) we eat, and fat. When energy is needed, glycogen is broken down to glucose, and this then fuels the metabolic engines in our body. The glucose/energy balance is regulated by many hormones, but insulin is the most important.

Those humanoids would also have eaten ripe fruit containing fructose, which would have been seasonal and available in great quantities, or not at all. This sweet fructose energy is stored as fat. Humans have an ability to store fat, in cells called adipocytes, to a greater degree than any other terrestrial mammal. The number of fat cells in an adult is constant and the cells grow as they accumulate fat. Adipocytes produce inflammatory products as they enlarge, producing far reaching effects all over the body, called The Metabolic Syndrome. Fructose is absorbed and metabolized differently to glucose and is independent of insulin. Fat is metabolized to energy usually after glycogen stores are reduced as in starvation, and is an important adaptation. So when you start your diet, you use up glycogen stores in muscle and liver and the water associated with it, and you lose weight quite quickly.

Metabolising the fat is where hard work, discipline and persistence come in. Fructose increases the deposition of visceral fat particularly in the liver, and prevents other hormones from breaking this down. Occasionally, increased fat deposition in the liver results in inflammation (NASH, Non Alcoholic Steato-Hepatitis) which may progress to Cirrhosis.

Humans are hard wired to look for food. The human neuro-endocrine system is set to hunger as default. The hypothalamus at the base of the brain regulates these impulses. There are more “hunger hormones” than “satiety hormones”. The satiety hormones increase only briefly when we have a meal, and are constantly challenged by the hunger hormones. We are almost constantly looking for our next meal. But as we got fatter, we had to expend more energy running after lizards and away from lions. With all these competing challenges we developed more complicated brains, to give us more options. What evolutionary biologists call Cognate Flexibility. What you and I call “the smarts”.

Looking at the historical associations of the obesity epidemic we see one important correlation. The massive production initially by the US, of corn syrup (from subsidised corn production) from about 1970 and its export internationally. Corn syrup contains both glucose and fructose, and began to be used in the developing fast food industry. Corn Syrup, modified further to High Fructose Corn Syrup (HFCS), was particulary attractive to the processed food industry and has a strong association with Type2 Diabetes and obesity wherever in the world it is exported to.

So we are designed to fall into this evolutionary trap. We are always hungry, and no longer have to deal with lions and lizards. There is always food available, and much of it is processed, containing sugars, including HFCS.

All this processed stuff ends up in our soft drinks, snacks, confectionery, biscuits, pizzas, and burgers. Switch on your TV. Advertising is awash with processed food. Almost all of it will contain sugars and HFCS. Remember, there is no biological need for any added sugar in diets. A half century of slick advertising has created a self-sustaining market.

How does the individual, the parent, respond? Eat food, not processed food. Drink water, not sweetened drinks. Make sure you have daily exercise. If you are obese, work with a dietitian for the long term. If you have a serious other illness, for instance severe T2DM, or sleep apnoea, or an obesity related cardiac condition, there is good evidence that obesity surgery, (bariatric surgery), can give good results. There are guidelines available (https://www.niddk.nih.gov/healthinformation/weight-management/bariatric-surgery/potential-candidates)

For Governments, the dimensions of the problem are daunting. Responses from all departments need collation and analysis to develop national legislation on many fronts. Leadership, that rare quality, is the challenge of our time.

(The writer is an Associate Professory of Surgery at James Cook University, Cairns, Australia)

Sugar and slavery Sugar, that sweet stuff, has an appalling history. The Portuguese in their early explorations colonized the Atlantic island of Madeira. They realized that cane could be grown, and imported West African slaves from 1433 to work the fields. Portuguese cane farming was then extended to Brazil, where more slaves were required. The other European colonisers, the British, Dutch and French also captured and exported slaves to the Caribbean to work their own cane fields. Later African slaves were transported to the new land of prosperity – the US. The ships that brought slaves to the Caribbean and North America, took back sugar, cotton and tobacco, the product of this slave labour, to Europe: a virtuous triangle of commerce. From the beginning of the 16th century to the middle of the 19th century 10 million West Africans were enslaved and transported. The Portuguese, Dutch, Brits, Belgians and even the French were enriched by this blood-soaked trade. A sickening story that should be taught in all schools. All this frantic trading activity made Europe and America seriously rich. But the effects in post-colonial Africa are still visible. In the US, the Civil War, partly inspired by a revulsion against slavery lasted from 1861 to 1865, and British politician William Wilberforce, a passionate Christian, brought this horror to a partial end with the passage of the Anti-Slavery Act in England, in 1883. A modern slavery still persists of course. We go along for the ride. So the sweet stuff has struck back at the heart of Western imperialism. But it strikes out in all directions to our cost. Most Lankans I know, have many spoons of sugar in their tea. Fortunately many others still have a small piece of jaggery which they lick deliciously from their palms.

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