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Picture: 123RF/milkos
Picture: 123RF/milkos

For years, people who are far overweight have had to put up with condescending attitudes — even from their doctors — as though their weight gain has been a failure of willpower. 

But people’s genes and not being able to buy healthy food easily — rather than a lack of self-discipline — have a much bigger role in why obese people struggle to lose weight and keep it off by exercising and restricting what they eat, research shows. 

Bariatric surgery (which makes your stomach smaller so that you eat less) or appetite-suppressant medicines (such as Ozempic) are the most effective ways for people with a body mass index (BMI) over 35 to lose weight. Someone is considered overweight when their BMI is 25 or higher, and obese when this number reaches 30 or more.  

The attitudes that obese and overweight people face is similar to those seen in the early days of the HIV epidemic, when people used to say that it was someone’s own fault for getting infected, says Francois Venter, an HIV doctor and director of the Ezintsha research centre, in an interview for an episode of The Bhekisisa Podcast

Thanks to effective new HIV medicines such as dolutegravir, which eliminates the disease as a medical issue, Venter’s patients are living long, healthy lives, and his role as a clinician is evolving too. 

These days, weight gain troubles so many of his HIV patients that it prompted him to look for solutions to help them. What he’s learnt in the process has led him to believe that the treatment of obese people is “one of the last great stigmas”.

Until now, Venter says, he’d been giving his overweight and obese patients advice based on the outdated view that exercise and diet are the key to weight loss. “I’m shocked at my own behaviour,” he explains during the podcast conversation.  

“Patients also used to think that they deserve to be HIV positive because they made bad life choices,” he added. Now, doctors and patients know that there are a whole lot of structural reasons for people becoming infected with HIV. 

In some communities (such as those where people live in poverty and with little education), someone’s chance of getting infected with HIV is high. The same is true of how societal issues affect obesity, but there’s still so much shame around the condition. “It feels exactly like HIV,” Venter says.

Here’s a summary of our interview with him.

What’s the link between HIV and weight? 

Weight gain, weight loss and HIV have a complicated relationship, Venter says.

When an HIV infection goes untreated, a person could lose weight because the virus weakens their immune system and makes them more likely to pick up infections that cause diarrhoea or result in problems with the body’s ability to absorb the nutrients from food. This is called “wasting”.

Taking medicines that keep the virus in check has reduced cases of HIV-related wasting, but the drugs themselves can still have an impact on someone’s weight. 

Older antiretroviral treatments such as stavudine made people lose weight (often in strange places, such as in their legs) because the medicine could affect the body’s ability to store and use fat. Stavudine isn’t used in South Africa’s HIV programme any more. 

Taking efavirenz is also linked to weight loss, and researchers think this is because people’s bodies struggle to break down the drug quickly enough, which interferes with normal metabolism. 

This drug’s use is declining too. The health department’s new HIV treatment guidelines (which haven’t been published yet) will cycle most people who are on efavirenz onto a regimen that includes the more effective drug called dolutegravir

People on dolutegravir pick up weight, but research shows it’s not the medicine itself causing this. Instead, it’s actually a sign that someone is returning to health because the treatment is good at thwarting the virus. 

Imagine telling an overweight person to diet and exercise. Then, when they don’t lose weight, you say: ‘You’re a bad person and you’re not taking our advice’
Francois Venter

Why would getting better on HIV treatment lead to weight gain? 

Dolutegravir is better than efavirenz at getting the levels of HIV in someone’s blood so low that it can no longer be transmitted during sex (this is called viral suppression).  

The drug also has fewer of the harsh side effects of earlier medicines, which could include dizziness, bad dreams, liver issues and problems with people’s metabolism. 

Venter says: “It seems that the older regimens were actually masking the fact that people gain weight when they get better on HIV [treatment].” 

With the newer drugs not preventing people from gaining weight any longer, there are also two other factors to consider. 

First, South Africans are genetically prone to obesity. A study that tracked a group of 990 black South African teens from the well-known Birth to 20 study, found three genes that were linked to having a higher BMI. “The best way to avoid becoming obese is to choose your parents well,” Venter says an obesity expert told him once. 

Second, research shows that the way South Africa’s cities and transport systems are set up isn’t helping. People who live far away from work may struggle to have meals at home and are more likely to buy food while they’re on the go, the researchers argue. 

These are often high in fat and refined starch, but have few other nutrients. Savoury snacks such as vetkoek, fried chips and kotas, soft drinks and ready-to-eat fast food are generally also cheaper than healthier options

The food industry is also constantly tailoring its products to make them more delicious, Venter says, so that you just can’t stop eating when you’ve had the first mouthful.

What happens once someone has picked up weight? 

It’s next to impossible for heavily overweight and obese people to lose weight without surgery or medicines, Venter says. 

He cautions that doctors should make sure they explain to patients starting dolutegravir that they can expect to gain weight on the medicine. 

“As a medical community — and as an HIV community — we need to start thinking very hard about what we do for people who are gaining weight. It would be terrible for people to stop taking their medicines because they’re worried about weight gain.”

Telling heavily overweight people to diet and exercise is not the way to do it, Venter argues, because research shows that this course of action only leads to weight loss in a small number of people

He explains: “Imagine telling an overweight person to diet and exercise. Then, when they don’t lose weight, you say: ‘You’re a bad person and you’re not taking our advice.’

“As clinicians, we’ve failed our patients.” 

What advice should doctors give their patients instead? 

Bariatric surgery and weight-loss medicines such as Wegovy and Ozempic “offer a great deal of hope”, but, says Venter, they’re not available in South Africa’s public sector because they’re so expensive. The medicine comes in a 1.5ml injection pen, which costs between R1,200 and R1,500. It’s injected weekly, and one pen can last somebody between one and eight weeks, depending on the weekly dose that their doctor prescribes. 

This situation also reminds Venter of the darker days of South Africa’s HIV epidemic. Back then, rich people had access to antiretrovirals, while those who relied on the state for health care did not.  

For nearly 10 years, from 1999 to 2008, the South African government largely denied that Aids was a disease caused by becoming infected with HIV.  

The country’s decisionmakers at the time (former president Thabo Mbeki and his health minister, Manto Tshabalala-Msimang) claimed poverty, malnutrition, haemophilia (a blood disorder) and drug use — and not HIV — were responsible for the devastating number of deaths Africa was seeing at the time. In 2005 alone, Aids deaths were estimated at 2.4-million

The government portrayed a drug known as AZT, by then a proven antiretroviral treatment, as poisonous and even claimed that it caused Aids.

Now, Venter says, the tools that reliably help overweight and obese people lose weight (surgery and medicines) are out of reach for poorer people once more. 

He says: “As doctors we’ll have to start thinking hard about better ways to help obese and overweight South Africans who want to lose weight. We have to go beyond suggesting they change their diet and exercise more — we know it won’t work.”

This story was produced by the Bhekisisa Centre for Health Journalism. Sign up for the newsletter.

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