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YOU can have your cake and eat it - but just once a week. The problem in a standard diet, says Robert Lustig, one of the world's most prominent crusaders against sugar, is "you are getting a dessert with every meal".
In 2009, Prof Lustig - who's a professor of paediatrics in the Division of Endocrinology at University of California, San Francisco - became something of a celebrity when his YouTube video titled Sugar: The Bitter Truth went viral. The 90-minute talk has since been viewed more than seven million times. In it, he sounded the alarm on fructose - a natural simple sugar found in fruit, honey and vegetables - which is contributing to obesity and diabetes. In the talk, he also took multinational beverage corporations to task, singling out Coca-Cola for contributing to the problem of excessive consumption of sugar. He even compared the 6.5-ounce Coke bottle of 1915 to 1992's 20-oz bottle to drive home the point about how much more sugar is present today in everyday food and drink.
Looking smart in a dark blue suit, the 60-year-old professor was in town in April for the Credit Suisse Global Megatrends Conference, where he spoke on longevity and nutrition. Talking to The Business Times after his session, he is viscerally candid and passionate about his anti-sugar crusade. "I came at it through the back door. I had no agenda. I wasn't even interested in obesity when I started. I took care of short kids. Then they grew fat on me."
In 1995, when Prof Lustig was an endocrinologist at St Jude's Children's Research Hospital in Memphis, Tennessee, he witnessed an inexplicable phenomenon: His young patients who had survived brain tumours became massively obese.
"The question is why, and what to do about it. It turns out that because of their brain damage, their brain wasn't sensing a hormone made from the fat cells, called leptin, which normally tells the brain one has (eaten) enough - but the neurons in these children were dead because of the tumour."
Research showed that these patients had very high levels of insulin - a hormone that regulates blood sugar levels. "So I used a drug that antagonised insulin release in these patients and they actually started losing weight and exercising spontaneously. What it showed was that it was the biochemistry that made them fat. The behaviour is the secondary response to the basic biochemical problem." Explaining how his findings apply beyond overweight, former cancer-stricken children to general obesity, Prof Lustig says: "It is the same problem."
Just as a brain tumour destroys the messages from leptin, the satiety hormone, high insulin levels also block out the leptin signals that inhibit hunger. And the reason for the high insulin levels is the way sugar - specifically fructose - is metabolised.
"Fructose is metabolised in the liver and when you overwhelm the liver with it, the liver takes the excess and turns it into liver fat. The liver becomes less responsive and the pancreas has to make extra insulin. Once the level of insulin goes up, it blocks the leptin signals and your body thinks it is starving. So you start eating like crazy and what is supposed to be a negative feedback pathway is now a positive feedback pathway, a vicious cycle which only continues to get worse."
The professor, who has a knack for breaking down fancy medical jargon into layman terms, adds that sugar is therefore the "alcohol of children" due to the way it is metabolised. In fact, he says, sugar is the reason that more children today are afflicted with two diseases - Type 2 diabetes and fatty liver disease - that are typically associated with alcoholism. "Before 1980, those were the diseases of alcohol, but children don't drink alcohol. It is because they have a different source - sugar."
Of course, critics will point out that fructose is found in fruit. So should people abstain from apples, oranges - the whole cornucopia? Prof Lustig has a ready explanation at hand. He says that while most people finish at most just one orange in a single sitting, people usually have more than a glass of orange juice at one go. "Fruit has fibre, which makes it self-limiting. In addition, fibre reduces the rate of absorption of fructose from the gut into the bloodstream so that your liver does not get overwhelmed."
In short, he cautions, while fruit is natural, fruit juice - stripped of fibre - is not.
Prof Lustig started giving talks on the toxicity of sugar in 2007 and back then, he had yet to embark on any specific research on the subject. He put together what he gathered from various literatures and made a coherent argument. Then, in 2015, Prof Lustig did a study that involved a "glucose for fructose exchange" in the meals of obese children. Bagels replaced pastries, baked potato chips replaced sweetened yogurt, and turkey hotdogs replaced chicken teriyaki.
"Basically, we switched the sugar in the diet with starch. All of the children's metabolic health got better. So while glucose can be a problem, because it makes your insulin level go up, fructose - because of the liver fat - is much worse. It is not that glucose is good; it is just that fructose is worse."
This study further highlights one of Prof Lustig's favourite catchphrases - "a calorie is not a calorie" - as it depends on where those calories come from, and where they go in the body to be metabolised.
The professor is in the process of doing another study, which is still in its nascent stage.
"It is too early to talk about it, but once we are finished, the research will document where in the body both glucose and fructose go, how they are metabolised and whether fructose is the primary trigger for metabolic disease."
To the sceptics and detractors who maintain that not enough research has been done on the harmful effects of sugar, Prof Lustig asks: "How much proof do you need to act? When do you actually have enough to say, you know what, we have enough data to do something. We now have categorical empirical proof. So the people who say there is not enough data are either ignoring it or (are being) paid off by the food industry."
To be sure, sugar is, for many people, part of the daily diet and those with an insatiable appetite for sweet stuff can, to a certain extent, blame it on how the human body is hardwired. "It's evolutionary. Because our ancestors knew that if something tasted sweet, it meant that it wouldn't be poisonous. The taste of sweet meant that something was safe to eat."
The problem, however, is that people are consuming too much sugar today. "In the old days, your grandmother, the only place she got sugar in her diet was when she added sugar to her coffee or tea. One lump or two, remember that? Well, no one says one lump or two anymore. And the reason is because it is everywhere. Now, because it has been added to everything, you don't know how much (sugar) you are consuming."
Prof Lustig co-authored the American Heart Association guidelines in 2009 that recommended no more than 100 calories (six teaspoons) of sugar per day for women and 150 calories (nine teaspoons) for men.
However, the Food and Drug Administration (FDA) guidelines in 2015 put it at no more than 10 per cent of one's daily calorie intake, which is 12 teaspoons of sugar.
How were the numbers derived?
Prof Lustig explains: "The World Health Organization (WHO) initially said 5 per cent, not 10 per cent, in 2014 because they were also trying to control dental caries, which is a huge problem around the world. But the food industry lobbied heavily, and ultimately, the WHO took that 5 per cent back and in 2015 said 10 per cent. And the United States Department of Agriculture (USDA), in order to be consistent with the WHO, said 10 per cent."
However, Prof Lustig points out that the American median consumption is 19.5 teaspoons of sugar a day - and getting down to 12 teaspoons would be a step in the right direction.
The bottom line is, he says, "one can make dog food taste good with enough sugar, and that is what the food industry does".
According to Prof Lustig, the food industry has learnt that when sugar is added to the product, people buy more of it. The reason is that one gets fatty liver after consuming too much sugar and becomes insulin-resistant. When the insulin level rises and blocks leptin, the brain sends the signal that one is starving and hence, the person eats more. "This is the perfect hook for the food industry. It is tantamount to legal addiction."
Prof Lustig recounts an anecdote. "We don't like brown rice, we like white rice, but the vitamins are in the husk. When I moved to San Francisco for a fellowship 30 years ago, every Chinese restaurant served brown rice, because it was healthy. I left and when I came back 17 years later, no one serves brown rice at the Chinese restaurants. Why? When they order brown rice, people would eat half a bowl; when they ate white rice, they ate two bowls. Because the brown rice had fibre, it was more filling. Here is the problem. In San Francisco, they charge for the rice. In New York, they don't charge for the rice. So in New York, they have brown rice. In San Francisco because they charge for the rice, they have white rice!"
Asked if he ever worries about the backlash from the food industry, the professor nods with a resolute "yes". "However, the truth is very powerful. And as long as I didn't overstep the science, I knew that the science would be my protection, my shield. I always stay within the science which is why I remain credible."
To curb the sugar epidemic, he is supportive of moves to implement a sugar tax, especially after seeing the results from Mexico, which introduced the "soda tax" in 2014. Sales of sugary drinks fell 5.5 per cent in the first year and by 9.7 per cent the second year.
Says Prof Lustig: "You have to do something to reduce effective availability. The iron law of public health says reducing availability will reduce consumption, which will reduce health harms. So the question is, how do you reduce availability? Well, there are many ways. Taxation is one way, and it is a low-hanging fruit."
He notes that there is now data from Mexico and Berkeley, California, linking taxation with decreased consumption. However, what is yet to be proven is whether a sugar tax effectively reduces diabetes. But data has shown that it takes three years to see the "changes in sugar and changes in diabetes so we have yet to determine that."
And, unfortunately for athletes and fitness enthusiasts, the professor also counters the assumption that with exercise, one can eat almost anything. "It is not about the calories. And it has never worked. There are no studies that show that exercise alone promotes weight loss. It is a myth. It is just not true.There is no way one can outrun a bad diet."
Looking ahead, Prof Lustig plans to further raise awareness about the dangers of sugar.
"We have a new administration in Washington and this administration is not interested in anything that resembles a regulation. In fact, they plan on undoing as many regulations as possible. The FDA had said that we would get a new nutrition fact label in America. That has been delayed. It may be rescinded. We don't know yet. It's been delayed for sure. So my job for the next four years is to get the medical, dental and the dietary professions to speak with one voice. So that when we do get an administration that will listen, we will be able to be impactful."
Prof Lustig also has tips for shopping healthier on that weekend trip to the supermarket, if one is at a loss as to what's best when faced with shelves upon shelves of brands. He says that if the food has a logo or label that one recognises, the food has been processed. "The reason is because if you recognise it, that means they (the companies) had money for marketing. Real food doesn't have a brand label, it also doesn't have a nutrition facts label because it is real. You only need to provide a label if it's been processed. So buy food without labels."
In fact, sugar is disguised under 56 different names, he says. Hence, contrary to what one may think, that snack you are holding right now may well be laden with quite a lot of sugar after adding it all up. "These are all business ploys that the food industry uses to get you to eat their product."
He cites the example of bread sold at the supermarket versus at a bakery, to drive home the point about the food industry profiteering at the expense of people's health. "In the supermarket, the bread has to have a long shelf-life. They add sugar to the bread to take the place of water because it won't evaporate, so the bread stays spongy and springy for longer. That is why grocery bread lasts so much longer than bakery bread.
"So when you understand these things that they do to the food - the food engineering - then you understand what's happened to our diets. And the food industry did it to make more money. That is why medical care and social security is going broke all over the world. Because the level of chronic disease from the processed foodstuff that we are consuming is killing us."
As the number of diabetics increase around the world - according to the 2016 WHO report, an estimated 422 million adults were living with diabetes in 2014, compared with 108 million in 1980 - people are opting to use sweeteners over sugar. However, Prof Lustig says that is an area where much more research has to be done.
"There are a lot of questions about diet sweeteners. We don't have the answers yet. But we have correlation data that says the diet sweetener is also associated with chronic metabolic disease. Now the question is why. Is it that people who are consuming diet sweeteners are also consuming sugar elsewhere and they know it, and they are trying to lose weight, or is it because diet sweeteners have bad effects on their own? We just don't know yet."
Asked whether he practises what he preaches and adheres to a strict low-sugar diet, Prof Lustig laughs and says that he tries most of the time to do the right thing.
"I used to be a stress-eater, I have learnt about my stress eating, so I am much more careful."
He adds that his Norwegian wife loves to bake as it is part of her tradition. "Whenever she is mad at me, she bakes. But she has learnt that she can take any recipe and she can use one-third less sugar and it tastes better because you can taste the nuts."
And this, Prof Lustig says, just goes to show that the amount of sugar used in commercially sold baked goods is "just heinous". "The reason they do it is because they know that when they add it, you buy more. And that is not OK."
As the interview winds to an end, Prof Lustig quips that he will be going out for some "real food". But not before this parting shot: "Real food is low sugar, high fibre. Processed food is high sugar, low fibre," he reminds this reporter, the photographer, and the public relations executive present for the session. And as he leaves the room, the obligatory bowl of sweets on the table remains, not surprisingly, untouched.
ROBERT H LUSTIG
Professor of Pediatrics, Division of Endocrinology and Member, Institute for Health Policy Studies University of California, San Francisco (UCSF)
Chief Scientific Officer of EatREAL, a non-profit dedicated to reversing childhood obesity and diabetes by impacting the global food supply
Fat Chance: Beating the Odds against Sugar, Processed Food, Obesity, and Disease (2013); and
The Hacking of the American Mind: Inside the Sugar-Coated Plot to Confuse Pleasure with Happiness (2017)
1957 Born in 1957, New York, US
1976 Graduated from MIT
1980 MD, Cornell University Medical College 1983 Completed paediatric residency at St Louis Children's Hospital
1984 Completed clinical fellowship at UCSF
Spent next six years as a research associate in neuroendocrinology at The Rockefeller University
2013 Masters of Studies in Law, UC Hastings