Wegovy drug not miracle obesity cure, warns weight-loss doctor

RNZ News

2 days ago

Semaglutide is a welcome tool against obesity, but patients should know the best way to achieve weight loss success.
Photo:
THOM LEACH / SCIENCE PHOTO LIBRA / TLE / Science Photo Library via AFP
A weight-loss doctor is warning patients not to rely on Wegovy as a cure for obesity, saying the newly available medication could be more harmful than helpful.
Waikato bariatric surgeon Dr Rowan French said Wegovy was a welcome tool in the battle against obesity, but it needed to be used in conjunction with psychological, exercise and nutritional support.
As with bariatric surgery, he recommended patients address the reasons they overate and the types of food they ate to avoid regaining any weight lost.
"People need to know that it's likely, particularly for someone who's living with severe obesity... their problem is a lifelong one and, while it can be controlled, there's a good chance they will never fully be cured of that.
"Without substantial change in their lifestyle - this is not just the foods they eat, it's the reasons they eat as well - without external help to understand their drivers to eat and nutritional help to understand the sorts of foods that they should be eating, particularly in the first 18-24 months, then the medications could prove more harmful than good.
"Particularly by causing some initial weight loss followed by substantial weight regain."
Wegovy contains semaglutide, an obesity medication that's a synthetic form of a hormone called GLP-1, which is made in the small intestine.
Ozempic is also semaglutide and works in the same way, but is licenced for type 2 diabetes rather than obesity.
GLP-1 plays several roles in the body, including triggering insulin release from the pancreas, and affecting areas of the brain that control hunger and satiety (feeling full).
Gastric bypass surgery causes amplified release of GLP-1 (and other hormones) from the small bowel in response to meals, which switches off appetite.
The release is cyclical, which means the hormone levels go up and down through the course of the day in response to eating, and goes directly into the gut circulation.
By contrast, Wegovy is injected under the skin in a large weekly dose into the systemic circulation.
"Here's the problem," French said. "We already know there is tachyphylaxis - the medical term for tolerance - that occurs with bariatric surgery as early as 18-24 months after surgery - there is a slowly waning effect.
"We can be almost certain that the injection of synthetic GLP-1 given in large bolus will cause tolerance earlier and more profoundly than bariatric surgery.
"In other words, as time goes on, the patient will get less and less benefit from the medication, so any suggestion some people should stay on it for life is unlikely to be sensible or beneficial."
French said that was where psychological and nutritional support, as well as exercise to avoid muscle mass loss, was vital, but "infrequently available".
"We know that weight regain is common several years after bariatric surgery, particularly if patients are not engaged in multidisciplinary follow-up.
"We know that, when semaglutide is stopped, in most cases, weight is regained, but we can also predict, if a patient stays on it, they will develop tolerance, because this occurs with bariatric surgery, albeit later in the piece."
French said people with a weight problem almost certainly had a lifelong disease.
"We are generally born with a likely predicted adult weight, which - in large part - is decided by our genetics... things that have happened to us in early life [trauma] and, to a certain extent, the environment.
"We have far less control over our long-term weight than most people think we do."
He said long-term weight control was subconscious - it happened in the "primitive brain".
"We can temporarily go on diets. We can temporarily override our primitive brain, but almost always this innate set-point... that we are born with dictates what our adult weight is going to be and it will drag us back up to that adult weight, despite going on diets."
Waikato bariatric surgeon Rowan French.
Photo:
Supplied
The aim was to control obesity, not cure it, French said.
"One of the things we see that raises that set-point is what we call 'cyclical dieting'."
Also known as 'yo-yo dieting', this is when a person loses weight on a diet, but regains it after the diet ends.
"Our primitive brain interprets that as starvation and it starts to fight back, and most people will regain the weight quite quickly.
"They will go back to a weight that was slightly higher and it's nature's way of putting more in the bank in case it happens again."
French said, when yo-yo dieting elevated a person's set-point to a new, higher level, the brain in turn defends that weight.
"So every time someone goes on a yo-yo diet and gains more, their weight set-point rises, so by the time we see people with severe problems who need treatment such as bariatric surgery, they might have done 10-12 diets.
"Each time their set-point has risen and it might have gone up 20, 25, 30, 35kg over a number of years."
French, who works in public and private, is speaking out, because he's concerned Wegovy has been sensationalised by celebrities as a wonder-drug.
While he said the new medications were the best New Zealand had ever had for weight loss, he stressed the need to address the causes of obesity.
One factor, he said, was the type of food people ate.
French said ultra-processed food (UPF) caused a spike in obesity rates in the mid-1980s and what he refers to as "pandemic obesity" in the western world.
"Essentially, you've got now a dominant food that makes up about 50-60 percent of what we eat, which is purely manufactured and designed to make us eat as much as possible.
"We know from the very robust data that it causes metabolic disease, it causes depression, it causes dementia, it causes cancer."
UPFs included most food that wasn't a whole food.
"Whole food being what your grandma would recognise as food," he said. "Very simply, if it's wrapped in plastic and it's got one ingredient that you wouldn't find in a home kitchen, that's an ultra-processed food."
The food was attractive because it was convenient, quick to prepare and easy to cook, and often less expensive.
French said it was often soft and easy to chew, low in fibre and didn't activate the hormone needed to make a person feel full, so people ate more.
"It's the combination of salt, fat and sugar that's always engineered to make it the most moorish it can possibly be."
French, who's private work is through Tailor Clinics in Hamilton, said his patients learn about eating whole foods at least 95 percent of the time.