Evidence is growing that calorie-packed sweeteners – such as high fructose syrups found in fizzy drinks, biscuits and cakes – have major roles in disease.Public health campaigns are now recommending strict limits to the consumption of these “free sugars.”
Part of the problem is that guidelines target sugar only for its calories rather than as a potential cause of illness, says US science writer Gary Taubes who specialises in diet and nutrition.
In an essay published in The BMJ he says the idea sugar could be behind the global obesity and diabetes epidemics should be considered seriously again.
Mr Taubes, co-founder of the Nutrition Science Initiative in San Diego, said it has potential deleterious effects on the body that go beyond just high numbers of calories.
He said a 15-fold increase in death rates from diabetes in some US cities since the Civil War coincided with the growth of the sweets, chocolate and ice cream industries in the 1840s and the soft drink industries in the 1880s.
In the midst of such a huge public health crisis, Mr Taubes says: “We must do more to discourage consumption while we improve our understanding of sugar’s role.”
Doctors have long suspected sugar is not simply a source of excess calories but a fundamental cause of obesity and type 2 diabetes, he says.
Until recently, fat consumption and total energy balance have dominated the debate about obesity and the nature of a healthy diet.
Official estimates are that one in 11 people in the United States has diabetes; one in 16 in the UK.Latest estimates suggest that obesity and diabetes may now cost the US healthcare system as much as $1bn (£740m; Euro 850m) a day.
In 2016, World Health Organization (WHO) director general Margaret Chan described the twin epidemics of obesity and diabetes worldwide as a “slow-motion disaster.”
She suggested the likelihood of preventing the current “bad situation” from getting “much worse” was “virtually zero.”In spite of all our best efforts these epidemics have gone unchecked, says Mr Taubes.
A simple explanation could be that our understanding of the cause of the disease is flawed – perhaps fundamentally so.
He said: “The US National Institutes of Health (crt Institutes) spent at least $750 million testing the hypothesis dietary fat consumption raises serum cholesterol and causes chronic disease.
“But it did not see the need to invest similar sums to answer the simple question, would we live longer and be healthier if we were given dietary advice to avoid sugar?”
The evidence that sugar has harmful qualities independent of its calories is still ambiguous.
Mr Taubes said: “If it is true, though, it changes how we must communicate the dangers of sugar consumption.”Setting an upper limit to the amount of sugar that should be consumed in a healthy diet is a good start.
“But we don’t know if the level recommended is safe for everyone.
“It could be that for people who have obesity or diabetes, or both, even a little is too much.”And the ubiquity of sugar rich products may make it difficult for many people to maintain a healthy level of sugar consumption.
“Given the scale of the obesity and diabetes epidemics “then a concerted programme of research to establish reliable knowledge on this subject should be among our highest priorities,” he concludes.
“Meanwhile, we can acknowledge the uncertainties while still recommending strongly against consumption.”
Mr Taubes is the author of The Case Against Sugar.
His previous books include the The Diet Delusion and Why We Get Fat.