Eating sugar can mean more than just added calories. But does it make you hyper or cause cancer? Not everything you hear about sugar is true. Here is the latest evidence to help you sort fact from fiction
What is added sugar?
There is plenty of naturally occurring sugar in the foods we eat – even bitter green vegetables like broccoli contain some. But “added sugar” – sometimes called “free sugar” – refers to any calorie-containing sweeteners added to food during preparation, whether in the factory or your kitchen.
Having more added sugar in your diet is associated with an increased risk of obesity and heart disease. That’s why the World 91ɫƬ Organization recommends getting from added sugar, and may soon ratchet that down to just 5 per cent.
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The US plans to on food labels in the future, though exactly when is unclear.
Are replacements like honey or agave syrup any better for you than plain old table sugar?
Not really. There are many types of sugar, each with their own level of sweetness and calorie content. Natural sweeteners often taste sweeter than table sugar, but can also have more calories per teaspoon.
Ultimately, to people who study nutrition, it all more or less balances out. Sugar is sugar.
Does sugar make you fat?
Yes. People who eat more added sugar tend to put on weight, and those who cut back on it . There are a few possible explanations for this. Most simply, people who eat more sugar tend to eat more, full stop.
But how you consume sugar also makes a difference. Drinking a sugar-sweetened beverage gives you an influx of calories without making you feel full – so-called “empty calories”. Eating an orange, with the accompanying fibre, makes you feel much fuller than drinking a glass of orange juice – even though the juice may have four to five times as many calories.
There are also other, more complex metabolic issues still being debated. The fructose is metabolised by the liver, and an excess can turn into liver fat. Having too much of this type of fat is associated with increased risk of a range of health conditions, including , a precursor to type 2 diabetes.
That is why researchers such as Robert Lustig have suggested that fructose may be uniquely harmful.
Glucose, meanwhile, can be taken up by all of the cells in the body with the help of the hormone insulin, produced by the pancreas.
The more glucose you consume, the more insulin your pancreas has to produce. And if you are consuming more than your body needs as fuel, the insulin will shunt the rest into your fat cells. Being overweight and having a high-sugar diet are also known risk factors for insulin resistance.
Can sugar cause cancer?
High sugar consumption is associated with cancer, but “it’s not really the sugar itself that is doing that”, says Debra Ruzensky, clinical dietician at the MD Anderson Cancer Center in Houston, Texas.
Put simply, it’s the association between consuming too much sugar and putting on extra weight that most strongly links sugar and cancer risk. People who are obese are at greater risk of a wide range of cancers, including of the breast, colon, pancreas, kidney and prostate.
Excess fat – especially around the midriff – also increases the risk of diabetes, which is itself a cancer risk.
Does sugar make you depressed?
A recent study found that men who eat more sugar are at higher risk for depression, but there was no corresponding association in women.
What the study did not show is the direction of causation. It may simply be that people who are already struggling with mental illness choose to eat more sugar.
Nonetheless, it is possible that sugar causes depression. Eating more sugar might conceivably affect the brain in various ways, “via dopamine or a nerve growth factor, bodily inflammation levels, over other related factors like obesity”, says study author Anita Knuppel at University College London. But the biology driving mental health conditions such as depression and anxiety is still not well understood.
Does sugar make you hyper?
No. More than two decades ago, researchers proved that there is , even among children who have ADHD or whose parents think that they are particularly sensitive to sugar. But no matter how many times this myth is debunked, the idea that eating sugar makes you hyperactive persists in the popular imagination.
The notion that kids have a sugar high is almost entirely down to parents’ perceptions. In one study, a group of parents noted hyperactive behaviour when told that their kids had been given sugar, despite the fact that they had not.
Are artificial sweeteners safe?
Aspartame, sucralose, saccharine, stevia. All artificial sweeteners approved by organisations such as the US Food and Drug Administration or the European Food Safety Authority are safe in terms of toxicological outcomes: that is, whether they cause cancer or pose a risk of abnormal fetal development at typical levels of consumption, says Allison Sylvetsky of George Washington University in Washington DC. “What we are less clear on is if they are helpful in terms of metabolism and appetite and weight,” says Sylvetsky.
There is some research to suggest that, in the strictly controlled setting of a clinical weight-loss programme, artificial sweeteners can help people shed pounds. Whether they are beneficial in everyday life or have downsides is not so clear-cut.
People who are overweight or obese tend to consume more artificial sweeteners, but it’s difficult to interpret this link. The same goes for any link between artificial sweeteners and increased risk of type 2 diabetes.
There are some mechanisms by which artificial sweeteners might increase risk of weight gain, says Sylvetsky. Sugar replacements are far sweeter than plain old table sugar. If you consume them regularly, that may alter your palate for sweetness, meaning you may opt for more sugary foods and end up eating more altogether.
The other possible mechanism is that fake sugars trick your body: if you taste something that is highly sweet, you then expect a hit of calories to follow. If that doesn’t happen, you may be left craving – and eating – more. In studies in rats at least, this seems to be the case. “Perhaps this disconnect leads to impaired energy regulation, and greater appetite,” says Sylvetsky.
Read more: Candy crusher – The man who turned the world against sugar
