Go to any children’s party, and you’ll hear that the kids are bouncing off the walls because they get to pig out on sugar, and sugar is toxic. Some parents will even forbid their children from partaking in the sugary treats.
The holiday period at the end of the year is traditionally a magical time for children. Hipsters might be a jaded by the glitzy excess, and those who observe religious days may frown on the shallow profanity of commercial Christmas, but most adults suffer the assault on the senses (and the pocket) for the sake of the young ones.
Charity organisations routinely get together to bring a little cheer to orphans and the children of the poor, so that even those who have nothing can feel a little special.
Imagine, then, my horror when I recently discovered that some parents send their children to parties, but forbid them to share in the sweets or sugary soft drinks the other kids consume. Their intentions are no doubt noble, but imposing such ascetic self-denial on children strikes me as particularly mean. Certainly, children should not routinely have access to sweetened drinks and snacks, but denying them treats even on special occasions can only breed resentment and rebellion.
What will those children do when they discover, as they are bound to do, that enjoying sugar or sweets on occasion is no risk to a healthy child? That there is no evidence whatsoever that sugar is linked to hyperactivity, attention-deficit disorder, or both? That rising obesity-related illnesses in some populations cannot be attributed to sugar?
In the US, where obesity levels are notoriously high, and where it has been studied extensively, consumption of food of all sorts has risen. Between 1970 and 2000, according to a paper citing official statistics, “the increase in per capita availability of total energy, sugars, carbohydrates, and fats was 25%, 22%, 26%, and 48%, respectively.”
It might seem logical to suppose that the correlation between eating more food and obesity might indicate a causal connection. There is great dispute about this, however. Some want you to believe the culprit is fat, others carbs, and others still, sugar.
The story that sugar is somehow “toxic” and is at the root of the so-called obesity epidemic stems mostly from the work of one man, Dr. Robert Lustig. Not shy of hyperbole, Lustig classes sugar alongside tobacco and cocaine in its addictive properties, the harm it causes, and the need for strict government-imposed restrictions on its use. A Guardian article that is not flagged as opinion, but is written by a reporter who openly declares herself to be “a convert”, summarises Lustig’s views. In it, the good doctor cheerfully admits to being 20kg overweight himself.
It wasn’t until two months ago that Lustig published the only paper in which he claims to “prove” (his word) that metabolic conditions such as diabetes and heart disease are not associated with obesity, but with sugar. It was widely picked up by the media, with the predictable headlines: “Sugar is definitely toxic,” Time magazine wrote, referring to Lustig’s “definitive evidence”.
These are big words, for a study on nutrition. Scientifically documenting people’s eating behaviour is notoriously difficult, since there are so many confounding factors between what a person is instructed to eat, what they tell a researcher they eat, what they actually do eat, what else they do that affects their health, and what turns up on their medical charts.
But Lustig was not at all uncertain. He personally took to the Guardian to announce his new proof, and demanded a sugar tax be instituted to reduce consumption. Presumably, then, Lustig studied loads of people under controlled circumstances. But no.
The evidence comes from a study of a mere 43 obese teenagers who routinely ate too much sugar, conducted over a period of nine days. During this extraordinarily short period of time, the children were given food to be “isocaloric” with (that is, match the caloric value of) their self-reported diet, except that two thirds of their dietary sugar was replaced by starch. If they lost weight, they were given more food. After nine days, several “surrogate metabolic parameters” were measured, leading Lustig to conclude that cutting sugar resulted in health improvements irrespective of body weight.
Unfortunately, 33 of the 43 kids did lose weight, which invalidates Lustig’s conclusion. The self-reported diets turned out to underestimate caloric intake, which had to be adjusted. This also contradicts Lustig’s conclusion. There was no control group of obese children who did not eat a diet with reduced sugar, which is only one of several study design flaws. Anybody who claims to be able to prove anything by observing 43 people on a nine-day miracle diet is probably lying. Lustig’s “proof” is nothing of the sort.
Some people believe that high-fructose corn syrup (HFCS), a common sugar substitute in commercial food and beverages, is the dangerous ingredient in sweets and soft drinks. The cause of this myth is a paper published in 2004, which notes a “temporal relation” between increased use of HFCS and rising obesity rates.
The theory was that because fructose is less readily metabolised than glucose, and is more likely to be stored in the form of fat, something called “high fructose” can’t possibly be good for you. But HFCS is only high in fructose compared to ordinary corn syrup (which consists predominantly of glucose). It contains a similar ratio of fructose to glucose as surcrose, or ordinary sugar, and goes through a similar amount of processing as sugar, too. Why the metabolism of fructose was an issue at all was left as an exercise for the reader.
That reader, if astute, would already have recognised, in “temporal relation”, a suspicious synonym for “correlation”. There is also a temporal relation between rising obesity rates and other things that rise over time, such as sea levels, organic food, free pornography, and electronic dance music. Correlation is not causation.
Two years later, a co-author of that study, Dr. Barry Popkin of the University of North Carolina’s Interdisciplinary Obesity Center, admitted to the New York Times that the paper was merely a “suggestion”. To wit: “It was a theory meant to spur science, but it’s quite possible that it may be found out not to be true,” Professor Popkin said. “I don’t think there should be a perception that high-fructose corn syrup has caused obesity until we know more.”
The admission came much too late, of course. Ill-considered “suggestions” like that spread like wildfire among the lay public, and become fact in roughly a week. The media ran with the hypothesis that greedy food factories using cheap HFCS were to blame for rising obesity and related diseases such as type two diabetes, especially in children.
In 2007, the paper that caused the HFCS scare was thoroughly dismantled: “The hypothesis that the replacement of sucrose with HFCS in beverages plays a causative role in obesity is not supported on the basis of its composition, biologic actions, or short-term effects on food intake. Had the hypothesis been phrased in the converse, namely that replacing HFCS with sucrose in beverages would be a solution for the obesity epidemic [it] would have been met with outright dismissal.”
Another popular myth is that sugar, or its surrogates, causes children to be hyperactive. It goes all the way back to Dr Benjamin Feingold, an allergist who published a popular diet opposing food additives in the 1970s. He listed a lengthy list of possible symptoms, any or all of which might be caused by additives of one sort or another, including sugar. Since every child on Earth will match at least some of the listed symptoms, it is absurd to conclude that any particular food or additive is the cause.
In particular, there is no convincing scientific evidence of a link between sugar and hyperactivity. As long as twenty-five years ago, scientists found: “Controlled studies have failed to confirm any effect on hyperactivity and effects on inattention have been equivocal.”
The UN Food and Agricultural Organisation based its recommendation upon a 1995 synthesis of the available literature: “[T]here is little objective evidence to suggest that sugar significantly alters the behaviour or cognitive performance of children. It is not appropriate to recommend restricting a child’s sugar intake for the purpose of trying to control their behaviour. If behaviour problems exist, it is important to identify the underlying reasons and to seek the existing and more rigorously established interventions for their treatment.”
Yet the myth persists. What really causes children to behave differently on occasions when they consume much sugar isn’t the sugar, but the occasion, doctors say. When they’re festive, they get over-excited. This can annoy parents. When they’re festive for too long, they get tired and cranky. This, too, can annoy parents. But children are just being children. If that annoys you, you probably shouldn’t have children.
Amusingly, a study in a child psychology journal did a controlled study of mothers who say their child’s behaviour is affected by sugar. All the children in the test – boys aged five to seven – were given a placebo, but some of the mothers were told their sons had received a large dose of sugar. It found the mothers who thought their children had consumed sugar rated their children as much more hyperactive. It wasn’t the child’s behaviour that changed, but the mother’s perception changed to match her expectation.
Parents fool themselves when they blame children’s behavioural or health problems on a single, easily-identifiable component of food or drink. It is a lazy way to think about nutrition, and creates overly strict rules for children.
It stands to reason that children shouldn’t eat sweets and snacks or drink soft drinks all the time. These, like fast food, ought to be treats, rather than substitutes for the balanced, home-cooked meals that children ought to get. In fact, the South African Journal of Clinical Nutrition found that childhood obesity were correlated with mothers who worked more than 36 hours a week, and speculated that this might be because children were given irregular fast food, rather than regular home-cooked meals. Sporting activity was also an obvious factor in childhood obesity. It also found that far more people consider price over health value when buying food, which leads to the purchase of less expensive, energy-dense foods to alleviate hunger.
The need for a regular balanced diet does not imply that occasional sweetened treats are in themselves “toxic”, or even unhealthy. It is arguably far worse for a child to be denied sweets on special occasions when everyone else does enjoy them. As long as the sweets or soft drinks don’t become routine, don’t be a Grinch this festive season.
Let the kids have their fun. They’ll have to go back to school and the routine of ordinary food soon enough. As a bonus, you’ll get to enjoy your own holiday without constantly having to nag the children and feeling guilty when they do get spoilt. Relax. The season is supposed to be festive. A little sugary treat is the least a happy child should be able to expect. DM
Stephen Hawking held a party for time travellers. He sent the invitation out the day after. Nobody attended.