For all their best intentions, parents may be giving their children the equivalent of alcohol for breakfast, says paediatric endocrinologist at the University of California Professor Robert Lustig.
Lustig, whose 2009 talk Sugar: The Bitter Truth is considered largely responsible for putting the spotlight on our sweet tooths, now says sugar has "similarity metabolically to alcohol" and is responsible for causing "two diseases that we never saw in children before 1980".
Indeed, research from last year found that our sugar intake is "alarming" and children are the worst offenders, with 76 per cent of children aged nine to 13 exceeding the guidelines for daily sugar intake.
It is not just fizzy drinks, lollies and chocolate bars, but "healthy" breakfasts that are doing harm.
According to the latest ABS statistics, children aged 2 to 3 were the most prevalent consumers of breakfast cereals (54 per cent), followed by 4-8-year-olds (52 per cent).
That's no big deal if they're eating plain oats, but few kids are. One analysis found that four out of the 10 most popular children's cereals are more than 30 per cent sugar. That's before sugar or honey has been sprinkled on top, fruit yoghurt added (a fruit yoghurt has about 30g of sugar) or they've had a glass of juice on the side (a large fruit juice can contain up to 60g of sugar per 500mL). The day has barely begun.
Ahead of a visit to Sydney in April, Lustig, who is releasing a new book later this year, The hacking of the contemporary mind: inside the sugar-coated plot to confuse pleasure with happiness, spoke with Fairfax about the trouble with sugar and whether we have to quit it completely.
Why is sugar so bad for us? What are the implications of consuming sugar?
Sugar is made up of two molecules. Glucose is the energy of life. Every cell on the planet can burn glucose for energy. But fructose is unlike glucose. Fructose metabolism does three things to damage our health: 1) Fructose overwhelms liver mitochondrial capacity, which promotes de novo lipogenesis and leads to hepatic insulin resistance, and which drives chronic metabolic disease. 2) Fructose binds to proteins via the Maillard reaction, promoting reactive oxygen species formation, which leads to cellular dysfunction and ageing. 3) Fructose promotes changes in the brain's reward system, which drives excessive consumption, similar to drug abuse. Fructose consumption is an independent risk factor for chronic metabolic disease, irrespective of its calories, and irrespective of its effects on obesity. The obesity and diabetes epidemics cannot be solved unless and until sugar consumption is reduced.
What has changed since your talk in 2009, both in terms of your own understanding and the public response to your message?
In the last seven years, we've made headway on two separate fronts. 1) We've shown in several ways that sugar is causative for diabetes and fatty liver disease. Not just correlative, but causative. 2) The addictive potential of sugar has become more apparent. Thus, we can demonstrate the "vicious cycle" of consumption and disease. Like tobacco, like alcohol. It is this paradigm that has led to societal sugar reduction efforts in many countries.
Instead of an anti-sugar message, many experts are promoting a 'sugar by half' message, based on the idea that most people don't follow the dietary guidelines and are as unlikely to quit sugar completely. What are your thoughts on this? Is a little really so harmful or is it the quantities we have it in that is doing the damage?
I know that Australia is involved in a "halve your intake" campaign. As far as I am concerned, any reduction is a good reduction. But it's not people I'm trying to influence. It's the food industry, who spikes three-quarters of the food in the grocery store with added sugar, so people consume it without realising it. A little is OK. A lot is not. Even if you consumed half as much from soda, cakes, cookies, ice cream, you would still be about double over your limit.
Do you believe we are consuming less of it now or are you seeing the same problems?
In America, we've gone from a median of 22 teaspoons per day to 19.5 teaspoons, a reduction of over 10 per cent [Australians consume slightly less, but are among the highest consumers of sugar in the world]. The problem is that our upper limit is about 6 teaspoons. So if you go from four times the upper limit to 3.5 times the upper limit, would you expect to see much change in disease prevalence?
What was it that led you to focus your research on sugar and what misconceptions do you still believe are out there about sugar consumption?
Its similarity metabolically to alcohol. There are two diseases that we never saw in children before 1980 — type 2 diabetes and fatty liver disease. Both of these diseases used to be the diseases of alcohol. But kids don't drink alcohol. It's not alcohol's calories that make it dangerous, it's the molecule itself. It's the same for sugar.
Do you believe sugar is the single greatest risk factor for obesity and chronic disease and, if so, why?
Obesity is multifactorial. Studies show that French fries and potato chips are the most associated with obesity, sugar coming in a distant third. But, remember, thin people get chronic metabolic disease too, and sugar appears to play a major role in the development of many of these diseases, such as type 2 diabetes, hypertension, lipid problems, heart disease, and dementia.
What role does insulin and leptin play in this?
Insulin is the bad guy. It does two things: 1) it drives energy deposition into fat cells, promoting weight gain; and 2) it blocks leptin signalling in the brain, so your brain thinks it's starving, thereby ratcheting up food intake.
Can personalised medicine assist in treating obesity and weight issues?
Absolutely. Not every obese person has the same reason for their weight gain. There are ways to parse the biochemistry. And different treatments are targeted against different pathologies. I will be speaking on this topic more, along with the whole subject, at the 5th BioCeuticals Symposium in April in Sydney.
Are there certain supplements or foods that can assist in weight loss? Are there foods we should be avoiding?
Refined carbohydrate drives insulin release, and sugar drives insulin resistance. These are the problem foods for most, but not all people. This is why personalised medicine is so important too – because there's no one-size-fits-all approach.
What will you be talking about in Australia?
My plenaries are titled, "Processed food: an experiment that failed" and "Targeting insulin in obesity". I will also conduct shorter sessions on the myths of the food industry, how to utilise history and lab data to make therapeutic decisions, and the role of personalised medicine in treating obesity.
What is next for you and how would you like to see the conversation about sugar/health/diet evolve?
I have a book that will be released in September, entitled The hacking of the contemporary mind: inside the sugar-coated plot to confuse pleasure with happiness. It will deal with behavioural health issues, and how they impact society negatively. I expect this book will be a conversation starter.
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