6 hidden truths about sugar, and how it's making us ill
Sugar is to children what alcohol is to grown-ups. There’s no good sugar, or fruit juice. Sugar, not obesity, is driving disease such as diabetes. Outspoken anti-sugar advocate Dr Robert Lustig reveals some not-so-sweet facts
Toxic, poison, a substance of abuse: these are words you probably don’t associate with sugar, but Dr Robert Lustig would convince you otherwise.
Lustig, a professor of paediatrics at the University of California, San Francisco, emerged as an outspoken leader of the global “anti-sugar” movement to improve global health when a presentation he made at the university in July 2009 went viral on YouTube. The video, called Sugar: The Bitter Truth, has been viewed more than 6.3 million times.
Recently in Hong Kong speaking at Credit Suisse’s Annual Asian Investment Conference at Conrad Hotel, Lustig emphasised the huge role the food industry plays in hiding the truths about sugar to the general public.
“The food industry don’t want you to know all of this because if you did, you would shop and consume very differently, and they don’t want you to because they’re making a lot of money,” asserts Lustig.
“It’s all about the money. And to be honest it’s OK to be about the money, but the food industry have to make money by selling food that is healthful, not by selling food that poisons people.”
Here are six hidden truths about sugar you probably didn’t know.
1. There's no such thing as “good sugar".
You may have been told there are “healthier” sugars like agave nectar, organic raw sugar, honey or coconut palm sugar. Not true. “Gram for gram, calorie for calorie, ounce for ounce, they’re all the same... the metabolic consequences are exactly the same,” says Lustig.
High fructose corn syrup has often been singled out as the major cause of obesity and disease, but it’s not because it’s more “metabolically evil” than other sugars, Lustig explains, but because it’s more “economically evil”. “Because it’s cheaper it made sugar cheaper, so it started appearing in all sorts of food that never had it before, particularly with low-fat food,” says Lustig.
The natural sugars found in fruit, however, are different because the fibre in fruit mitigates the negative effects, he says.
2. Fruit juice is the same as soft drinks (even these trendy cold-pressed raw juices from “slow juicing" machines).
There may be no added sugar in 100 per cent fruit juice, but once you take the fibre away, the natural sugars might as well be added, Lustig says. “People think juices are healthy because fruit is healthy, but once you juice a fruit, it’s the same as a soda.”
Even with cold-pressed “slow" juice, the soluble fibre may still be retained but the insoluble fibre is in the bin, he says. “Soluble fibre is like pectins, it holds jelly together. Insoluble fibre is the cellulose, like the stringy stuff in celery or grapefruit. You need both,” he explains.
“On the inside of your intestines you have epithelial cells. The insoluble fibre forms like a latticework covering these epithelial cells, and the soluble fibre plugs the holes between. And what you end up with is an insoluble barrier that limits the rate of absorption of the sugar that’s in the intestine from getting into the bloodstream. Maybe some of it won’t get absorbed at all; it’ll go further down the intestine to the gut bacteria, which chew it up instead of you.
“So when you consume it as fruit, it’s all good. When you consume it as juice and there’s no insoluble fibre, you can’t make that barrier, so the sugar gets absorbed just as fast as it did before in the liver, and you get just as sick.”
Along the same lines, eating dietary fat doesn’t make you fat, says Lustig. If you ate 160 calories of almonds, for example, your body only absorbs 120 calories because the gut bacteria chews up the other 40 calories.
“What passes your lips doesn’t necessarily reach your systemic circulation and that has to do with what else you’re eating, most important of which is fibre,” says Lustig.
3. Glucose, sucrose and fructose: all sugar, but processed differently in the body.
Consider two slices of white bread versus orange juice, Lustig explains. The bread contains 120 calories of glucose (what Lustig calls “the energy of life”), and the juice contains 120 calories of sucrose. Of the 120 glucose calories in bread, 80 per cent (or 96 calories) will be used to fuel the body’s organs. The unused 20 per cent goes to the liver, where some will be converted and stored as glycogen for later use, and some will be released into the bloodstream. That stimulates the pancreas to produce insulin, which regulates blood sugar and helps signal the brain that you are full. Most of the stored glycogen will get burned off as your body needs it. Just a tiny fraction of the glucose leaves the liver as citrate and is ultimately turned into fat.
Compare this to the sucrose in the orange juice, of which 60 calories is glucose and 60 calories is fructose. Fructose can be processed only by the liver and cannot be used by other organs, so all 60 calories will be processed there, where it creates toxic by-products like uric acid. High levels of uric acid is linked with several obesity-related diseases such as gout and hypertension.
4. Sugar, not obesity, is driving metabolic diseases such as type 2 diabetes and non-alcoholic fatty liver disease.
It’s no question that people who are obese have a higher risk for metabolic diseases, but it’s not true that obesity is driving these diseases, including non-alcoholic fatty liver disease, the “fastest growing epidemic in the history of the world”, Lustig says. Hong Kong, for example, has a much lower obesity rate yet a much higher diabetes rate than the US.
Lustig cites statistics from the US: among 240 million adults, 30 per cent are obese (a body mass index of 30 and above). Eighty per cent of this 30 per cent are obese and sick, a total of 57 million people. Among the 70 per cent of the US adult population who are not obese, 40 per cent, or 67 million, have exactly the same metabolic dysfunction as these obese and sick people. These people are medically known as “TOFI – thin on the outside, fat on the inside”. Based on this, Lustig suggests metabolic diseases are not about behaviour but rather exposure – in particular to sugar in processed food.
A study by Lustig and colleagues that was published in the February 2016 issue of the journal Obesity provides evidence that liver fat is driving the rise in metabolic diseases. Children who had metabolic syndrome and who were obese were fed catered meals for 10 days in which sugar was substituted by starch. So instead of donuts, the children had bagels; potato chips instead of sweetened yogurt; turkey hot dogs instead of chicken teriyaki. “We didn’t even give them good food; we gave them lousy, processed, kid food – but with no added sugar,” says Lustig.
Calories – from fat, protein and total carbohydrate – all remained the same as the children's regular diet. After 10 days, there was a 22 per cent reduction in liver fat among the children, but not much change in visceral and subcutaneous fat. As the liver fat went away, the children’s metabolic health improved, Lustig says.
“So the question is, where did the liver fat come from?” he asks. “Before 1975 the answer would have been alcohol, but kids don’t drink alcohol. It came from sugar; sugar and alcohol gets metabolised exactly the same way in the liver. Sugar is the alcohol of a child. And that is why today, children are getting the diseases of alcohol – type 2 diabetes and fatty liver disease – without alcohol. Sugar has gone up the most in every civilised society in the world; it’s called processed food.”
5. The link between sugar consumption and obesity is backed by “very weak” scientific data.
While sugar is proven scientifically to cause type 2 diabetes, heart disease, fatty liver disease and tooth decay, the data on sugar and obesity is very weak, Lustig says. “But the food industry don’t want you to know that.”
“Sugar is about 10 per cent of the total obesity burden; it’s about 0.8 BMI points. But we have a 7-8 BMI point problem. So the food industry always refers back to obesity, because people assume that obesity is about behaviour. The food industry will say, ‘why pick on our calories if sugar is only 10 per cent of the problem? Go pick on potato chips and French fries.’
“But it’s not about obesity and that’s not where the money goes – the money goes to the chronic diseases, type 2 diabetes, fatty liver disease, heart disease, tooth decay, cancer and dementia which are chronic metabolic diseases.”
6. Reducing sugar consumption would require a team effort from food industry stakeholders and refereeing by the government.
Lustig gives the example of Britain's successful Action on Salt initiative, a nationwide salt reduction programme that began in 2003/2004 and successfully reduced population salt intake by 15 per cent in 2011, and simultaneously a 40 per cent reduction in deaths from hypertension and stroke.
“Action on Salt is an NGO that petitioned the Blair government in 2003 and by 2006 they were sitting down with the food industry. And basically the Blair government told the food industry, ‘you don’t have a choice in this, but we’re going to make everyone do it together, to cut the salt in the British diet in steps over years – 10 per cent cuts each year over four years to reduce the salt content of food by 40 per cent. And we’re not going to tell anyone we did it.’
“The British public didn’t even know. It was a public health win, but it couldn’t be done by any individual company – it had to be done by the government serving as the referee. Could the processed food industry do that today? Absolutely, if they were all willing to sit down.”
In March, the British government announced a sugar tax in the form of a levy on sugary-drinks manufacturers. The tax, which will come into force in 2018, will add 24 pence to a litre to soft drinks with the highest sugar content, a cost that could be passed on to shoppers through higher prices.
Mexico, France, Hungary and Finland, among others, have already taxed sugary drinks; South Africa, the Philippines, Indonesia and India are considering doing so.