48 | New Scientist | 7 May 2022interventions, such as diet and exercise.
Those given the drug lost, on average,
around 15 per cent of their body weight
during the 68-week trial, compared with
2.4 per cent in the placebo group.
Experts are cautiously impressed by these
results, and semaglutide was approved by the
FDA in June 2021, the first weight-loss drug to
gain such approval since 2014.
As well as working well compared to a
placebo and lifestyle changes, it also compares
favourably to other available weight-loss drugs,
because it targets a hormone in the body, rather
than just targeting the brain, says Wadden.
Contrave, for example, is a combination of the
antidepressant bupropion and the addiction
drug naltrexone. It works on the hypothalamus
to help regulate appetite, but it doesn’t provide
the double whammy of satiation on the gut,
and people taking it typically lose between
5 and 10 per cent of their body weight. Those
taking it also commonly experience dizziness,
a dry mouth, insomnia and intense dreams.
Other drugs work by blocking the digestion
of fat in the foods you eat, so that about a
quarter of it is excreted in your stools rather
than being absorbed during digestion. This
more primitive method results in around a
5 per cent weight loss and is accompanied by
some pretty unpleasant side effects, such as
loose stools, oily faeces and incontinence.
With semaglutide, by far the most commonissues have been gastrointestinal. Forty-five
per cent of trial participants reported nausea
and 30 per cent experienced diarrhoea or
constipation. Vomiting affected 24 per cent.
This can put some people off, says Fatima
Stanford at Massachusetts General Hospital.
“When you hear that 45 per cent of patients will
have nausea, that is high. Some of my patients
fear having it and won’t try the medications
as a result.” Another 5 per cent developed
gallstones due to the rapid nature of the
weight loss, requiring surgery in some cases.
For the most part, however, doctors have
been able to mitigate side effects by starting at
a low dose and slowly increasing it as the body
develops a tolerance and symptoms subside,
says Patrick O’Neil, director of the Weight
Management Center at the Medical University
of South Carolina. Only about 3 per cent of
participants dropped out of the trial due to
side effects. Still, we don’t yet have data on
any long-term effects.Lifetime commitment
The hope is that semaglutide could help people
like Rhinehardt finally reach a healthier weight
and, more importantly, keep it off. In fact, the
drug’s approval seems to be accompanying a
shift in the way that obesity is being treated,
at least in the US, with the FDA categorising
weight-loss drugs differently, says Robert
Kushner, a endocrinologist at Northwestern
University in Illinois.
Semaglutide, for example, is in a new group
of drugs called anti-obesity medications that
are approved by the FDA for chronic weight
management, an acknowledgement that the
issue with obesity often isn’t just losing the
weight, but keeping it off. “Those of us that
work in this field think of obesity as not just
about losing weight, but about how we treat
the disease of obesity and all the metabolic
and health conditions that are associated with
it,” says Kushner. Some people may need help
keeping the weight off for the rest of their lives.
These drugs are approved for both weight
loss and weight maintenance, which means
they need to be thought of as long-term
solutions for a chronic relapsing condition,
says Kushner. Similar to diabetes or high
blood pressure medications, if you stop
using the drug, the condition is likely to
come back. Once people start taking it,
they will probably need to do so forever.In the US, 228,000 weight loss
surgeries were done in 2017.
The most popular type is sleeve
gastrectomy, where three-quarters
of the stomach is cut out so the
individual can’t eat as much. In the
two years afterwards, people see
a mean weight loss of 20 per cent.
Although we don’t have long-term
data for the weight-loss drug
semaglutide (see main story),
Thomas Wadden at the University
of Pennsylvania says that if people
on the drug maintain their weight
loss for two years and it is cost
effective, they may choose
it instead of surgery. It is the
first weight-loss drug to show
comparable results to surgery.Pills vs surgery
Some older drugs
block digestion
of fat in foods –
with nasty
side-effectsBS
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