By NewScientist
If you know one thing about obesity, you probably know that people have been gradually getting heavier for the past few decades in nearly every part of the world. This is widely agreed to be a major public health problem, but there is less agreement on what we should do about it.
One strategy on the table in many countries is to tax certain food and drinks at higher rates. In theory, this would nudge people into eating and drinking more healthily and encourage manufacturers to make their products less unhealthy.
The UK was among the first countries to have actually done this, in 2018, when it introduced higher taxes on drinks with added sugar. A study out this week has been widely reported as finding that this strategy helped to reduce weight gain in girls aged 10 to 11 in England.
Unfortunately, the real picture appears more complex. The claim is based on the fact that before the tax there was a trend of gradually rising obesity levels among girls this age. After the tax was announced in 2016, the rise started to plateau, culminating in an 8 percent difference between the observed obesity level and the expected one in 2019.
But it’s debatable whether the sugar tax really is responsible for this small difference, as no such effect was seen in boys or younger girls, as I cover here. And sadly, the small difference seen in older girls has since been swallowed up by a bigger jump in obesity rates in all children during the school closures amid the covid-19 pandemic.
The continuing rise in childhood obesity means we must do something about it, but the sugar tax isn’t universally popular. When the UK government announced the details in 2016, many manufacturers changed their recipes, replacing some sugar with sweeteners, even in products not marketed as diet drinks. The upshot is that, unless you carefully read labels, it can be hard to avoid consuming sweeteners in soft drinks in the UK.
Certain people dislike the taste of sweeteners and others avoid them because of possible unwanted health effects. While some research suggests that diet drinks help people lose weight, other studies have found they can stimulate appetite, raise blood sugar levels, or have other undesirable metabolic effects.
If it seems implausible that a food ingredient widely used for decades could turn out to be harmful, it has happened before – witness the U-turn over “trans fats”. These are a form of fat made when vegetable oils are processed so they become solid at room temperature.
Trans fats in processed foods became more common in the mid-20th century, especially when health bodies said people could lower their risk of heart disease by switching from animal fats, such as butter and lard, to vegetable margarine and cooking oils. But it emerged in the 1990s that trans fats are actually much worse in terms of causing heart disease than the animal fats they replaced.
Today, most spreads and processed food containing vegetable oils are made in a different way, so they contain very little trans fats. But artificial trans fats were only banned in the US in 2018 and in the European Union in 2021. It shows that the food industry – and official health advice – doesn’t always get things right.
Along similar lines, I wonder whether it is right for public bodies like schools and hospitals to switch to vegan burgers and sausages for environmental reasons – as was proposed this week – when the health effects are still unclear. Such foods are usually highly processed and there is growing evidence that the rise in obesity is linked to people eating more highly processed food, as we have previously reported here.
I am not trying to scaremonger about sweeteners. They are completely safe according to the UK health services and I am happy to consume them – although the issue is less relevant to me as my preference is to drink vast quantities of tea throughout the day. (If we ever find out that tea is bad for us, I will be in deep trouble.)
Unpalatable
The continuing rise in rates of obesity is clearly an increasing public health problem that every government wants to fix. The trouble is, we don’t know how to.
Even organisations that are in favour of the sugary drinks tax, such as the UK’s Action on Sugar, acknowledge that this measure doesn’t have a big enough effect on total sugar consumption. Such bodies tend to argue that health taxes are needed on food products too. But making food more expensive seems politically unpalatable in the middle of the UK’s cost-of-living crisis.
Other proposals include banning junk food advertising, enforcing smaller portion sizes of snack foods, and even banning eating on public transport. This last off-the-wall suggestion was one of 49 proposals in a report by England’s former chief medical officer Sally Davies in 2019. At the time, I asked the government for supporting evidence behind a public transport snack ban, but it refused to provide it.
The sad fact is that not a single country in the world has reversed or even halted the trend of rising obesity rates, as far as I know. The American Academy of Pediatrics has just released guidelines for treating children with obesity that recommends offering stomach surgery to those as young as 13 and weight loss drugs from 12 years old.
The one proposal in Davies’s report that needs to be acted on most urgently is more research so we can better understand how to tackle the obesity problem. But anyone claiming there is a simple solution is misguided.
Source: New Scientist
