The sweet habit healthy girls can’t quit
You live on kale and sprouted bread, but still crack open a daily diet soft drink. But is this ‘harmless’ sip sabotaging your body goals? WH investigates
Could this one ‘harmless’ thing be sabotaging your wellness goals?
Picture the scene: Lunch has come and gone and, in offices across the land, Tupperware once home to preppedahead sweet potato, chickpeas and spinach lie empty. The temptation to attack the office tub of mini brownies is oh-so-real. But rather than blow a truckload of kilojoules on cake, women nationwide reach for something else instead: ‘guilt-free’ cans of chemically sweetened carbonated liquid. Are they hypocritical self-saboteurs for following healthy, totally ’grammable meals with a diet fizzy drink? Perhaps, which makes it all the more difficult to admit that I’m one of them. A health writer who knows her nutrition – and should know better – but can’t get enough of the stuff. Journalist Georgia Scarr is another self-confessed fan. Glance at her Instagram and you’ll see all the healthy-girl hallmarks. Bird’s-eye view of eggs atop kale and roasted veg? Check. One lithe, toned body contorted into impressive yoga positions? Check again. But one lifestyle ritual that doesn’t make the edit is her diet cola habit. “I have a sweet tooth, but I don’t make a habit of eating junk food,” she says. “I monitor my [kilojoules], and want them to be from nutritious food and drink, not sugar. But then the craving for something fizzy hits. I know diet drinks aren’t good for me and can’t say I’m proud of my habit.”
So what’s going on? The enduring appeal of kilojoule-free fizzy pop might jar with the current ‘it’s a lifestyle, not a diet’ healthy-eating Zeitgeist, but Jane Ogden, professor of health psychology at the UK’S University of Surrey and author of The Psychology of Eating, isn’t surprised. “So-called ‘diet’ drinks still appeal because, though people may package it as ‘eating well’ or ‘looking after yourself’, many of us are essentially still dieting,” she explains. And while our goals may be more rippling abs than thigh gap, she is right in that the majority of us want to keep our body fat low. “The word ‘diet’ carries powerful connotations of being lean, healthy and in control,” Ogden explains. “So while we continue to aspire to those things, ‘diet’ labelling will draw us in – even if we’d rather not admit it.” Put like that, our fondness for diet drinks doesn’t seem so incongruous.
But the million-dollar question: is cracking open a can sweetened with chemicals such as sucralose and aspartame actually helpful when you’re trying to get – and stay – lean? Science says, perhaps not! A study in The American Journal of Clinical Nutrition found those who guzzled one litre of a diet fizzy drink daily gained 1.5kg after six months. The group who drank full-sugar soft drinks gained 10kg. So the diet option had less of an impact, sure – but why did the diet-drinkers gain weight at all, given these drinks are both kilojoule- and sugar-free?
As it stands, there’s no evidencebased answer. But Robert Lustig, professor of endocrinology at the University of California and antisugar campaigner, has a possible explanation: that consuming artificial sweeteners can alter your biochemistry and predispose you to gaining fat. “The diet soft drink group gained weight not because they were increasing their [kilojoules], but because their insulin levels had risen,” he says. “The more insulin you have in your blood, the more [kilojoules] you’ll store as fat. So anything that raises insulin will make you gain weight.”
Translation: Because they don’t contain any actual sugar, artificially sweetened drinks shouldn’t technically spike insulin. But in a study in the journal Diabetes
Care, researchers split their study participants into two groups and supplied half with a diet soft drink. They tested their insulin and glucose levels afterwards and found 20 per cent more insulin in the blood of those who’d drunk the artificially
sweetened drinks than those who hadn’t. Why? It’s all down to the fact the body is primed to detect sweetness. So when something sweet hits your tongue, specific receptors are triggered. “First, they send a message to the brain to say that sugar is incoming,” says Lustig. “Then the brain sends a message to the pancreas telling it to expect the sugar, so it prepares to release insulin.” But when you drink an artificially sweetened drink, the sugar never comes. Result? The pancreas sends out the message you need to seek out more glucose to trigger the release of its insulin.
Case in point: Yasmin, 25, drinks several cans of diet fizzy drinks a week to help her stick to a ‘no-sugar lifestyle’. “It means I can have the sweet taste without consuming any actual sugar,” she says. Down nearly 13kg, and hitting the gym four times a week, Yasmin is determined to maintain her methods. “If these drinks help me stick to a plan that works, I don’t see it as a problem,” she says. But Lustig warns that Yasmin may be making life harder for herself. “Drinking artificially sweetened drinks when you’re not eating real sugar is self-defeating,” he says. “The point of a ‘no-sugar lifestyle’ is to desensitise yourself to sweet foods, but if you’re regularly consuming sugar-free fizzy drinks, then you’re re-sensitising yourself.”
So, the jury’s out on whether slimmers should sip so freely – and there’s also still much we don’t know about how artificial sweeteners are linked to disease risk. While a recent study by Boston University School of Medicine did show that people who drank diet drinks had an increased chance of dementia and strokes, lead author Dr Matthew Pase cautions this is early research – so it’s impossible to gauge cause and effect. As for claims that sweeteners such as aspartame could cause cancer? “The balance of evidence is that artificial sweeteners are safe for us to consume,” says clinical dietitian Rick Miller. “Some experiments on mice demonstrated a link between aspartame and the growth of cancerous tumours – but it is not clear if we can directly relate these results to humans.”
Miller’s message for us habitual drinkers? Don’t freak out, but do cut down – on all fizzy drinks. “Regular and diet varieties contain phosphoric acid, which research suggests can reduce bone mineral density,” he says. And let’s be clear – a stress fracture caused by weak bones is going to have a worse effect on your aesthetic and athletic goals than a few mini brownies. Still, I can’t promise that I won’t have had a sneaky sip of my old poison by the time you’ve read this. But if I do choose to crack open a can, it certainly won’t be done mindlessly. Because, while a part of me may still be sold on the zero-sugar, zero-kilojoule promise, there’s a big chance that my body is not.