Save articles for later
Add articles to your saved list and come back to them any time.
Dip into vintage copies of National Geographic from the 1970s and among photos of wildlife and archaeological wonders is a glimpse of how humans used to look. In images from 50 years ago, more people are lean, fewer are overweight – even in places now prone to obesity like rural USA and Australia.
Fifty years on, obesity rates have almost tripled globally, increasing chronic disease, stunting life expectancy – and even messing with fertility. But we now have new drugs that could help make weight loss more successful. Semaglutide (known as Ozempic or Wegovy) is one, and there’s also tirzepatide (Mounjaro) which is only approved in Australia for type 2 diabetes (and not yet available here), but is expected to be approved for weight loss in the US this year.
Is it time to recognise that treatment is necessary for obesity?Credit: Dionne Gain
With more anti-obesity drugs in development, this could be the brink of a new era of better medication for obesity. But the chorus of disapproval keeps on: ‘people just need more willpower’.
So did those long-haired folks back in the 1970s simply have more willpower? No, sighs Associate Professor Priya Sumithran, a researcher at the University of Melbourne’s Department of Medicine and head of obesity medicine at Austin Health.
“Obesity is more complex than people realise. We all want to believe we have control over our weight but our susceptibility to weight gain is influenced by many different genes, and some people have more stacked against them. These genetic differences have always existed – but 50 years ago we didn’t have the environmental conditions, particularly inexpensive, hyper-palatable, high kilojoule food, to bring them out so powerfully,” she says.
When food is scarce, those same genetic differences have a survival advantage – but in countries oversupplied with highly processed food they’re a liability, adds Associate Professor Samantha Hocking of the University of Sydney’s Charles Perkins Centre.
“Prevention and treatment are not the same.”
“Once weight is on, these genes work overtime to keep it there. Metabolism slows down to conserve fat, appetite increases and the brain becomes less sensitive to fullness. For many people it’s impossible to shed enough weight with healthier diets and exercise alone but these newer drugs make it possible by putting a wet blanket on those fiery signals to eat. For those people, these drugs aren’t the easy option, they’re the only option. ”
Sumithran puts it another way.
“Many studies show that healthy diets and exercise are often not enough once obesity has developed. Prevention and treatment are not the same. We know that healthy lifestyle habits can help prevent some cancers, for example, but if someone develops cancer, we don’t say they just need good nutrition and exercise, they also need treatment. It’s not either or.”
Science has been trying to nail an effective weight loss drug for almost a century, with mixed results. Amphetamines fell out of favour in the 1970s because of the risk of addiction, while sibutramine, launched in the 1990s to reduce appetite, was withdrawn because of the risk of cardiovascular disease. But while there are prescription drugs for obesity – including orlistat, which helps block the body’s absorption of fat – none work as well as the newcomers, semaglutide and tirzepatide.
Studies have found that people lost around 15 per cent of their weight over 68 weeks with the highest dose of semaglutide, while those on the highest dose of tirzepatide lost 22.5 per cent of their weight after 72 weeks.
What sparked this shift towards better drugs?
“It’s a clearer understanding of the links between the gut and the brain, and the role that gut hormones play in weight and appetite,” Sumithran explains.
More weight loss drugs are in the research phase – including one to help promote muscle development while reducing fat. But those that target gut hormones are the most promising, she says.
How safe are semaglutide and tirzepatide – drugs that may need to be taken lifelong in order to maintain weight?
“Like all new medications, we won’t know until they’ve been in use for a while but they’re similar to drugs that have been safely used to treat type 2 diabetes for 20 years. They also work in a different way to other obesity drugs that have come before,” says Sumithran.
Does weight loss helped by these newer drugs also translate into better health?
“Studies so far have found that semaglutide and a similar drug liraglutide help protect against heart disease and stroke in people with type 2 diabetes,” says Hocking.
But not everyone is eligible for weight loss drugs.
“You need to have either a BMI of 30 or more, or a BMI of 27, along with a condition related to overweight such as high blood pressure or obstructive sleep apnoea,” she adds. “But these groups represent around one-third of the Australian population – so the cost of putting anti-obesity drugs on the PBS is considered too high. Yet people who need the help of these drugs most are often those
who can least afford them.”
But semaglutide is in short supply. Stocks of the lower dose version, approved for diabetes in Australia, are unavailable in Australia until the end of March. While Wegovy is registered for weight loss in Australia, it’s unclear when it will be available, Sumithran says.
These drugs won’t fix obesity all by themselves. They’re an add-on to healthy diets and exercise – not standalone treatments. We also need other strategies, including a crackdown on marketing the junk food fuelling obesity. And let’s quit braying about willpower too – and try to grasp the complexities of obesity instead.
Make the most of your health, relationships, fitness and nutrition with our Live Well newsletter. Get it in your inbox every Monday.
Most Viewed in Lifestyle
From our partners
Source: Read Full Article