First published Winter 2018


A drug to aid weight-loss could be the answer to many prayers; both individual and corporate. But could relying on a pill have unpleasant consequences short- and long-term? Ellie Smith writes


Many of us will have fantasised about a magic pill to help shed a few pounds at some point in our lives. So it comes as no surprise that reports claiming scientists have discovered the ‘holy-grail’ of weight-loss medicine caused a big stir. In a study published in the New England Journal of Medicine, appetite suppressant lorcaserin has been deemed a safe and effective weight-loss tool — three times more effective than dieting, according to researchers.1

Populations around the world are struggling with their weight. In the UK alone, obesity rates are worryingly high with almost one in three adults now obese and another 36 per cent overweight. As a result, obesity-related hospital admissions have doubled in the past four years, putting a huge financial strain on the NHS. The need for change has never been more pressing — but are over-the-counter pills really the answer?

 “Everyone is looking for this magic bullet for weight-loss but unfortunately there isn’t one,” says registered nutritional therapist Catherine Jeans. “Fundamentally we have to address the underlying issues and look at dietary and lifestyle modifications.”

 Weight-loss pills are not a new concept. Since the 1960s a number of ‘breakthrough’ drugs have appeared on the market, only to be recalled after being found to increase the risk of cardiovascular disease. Crucially, scientists have concluded those using lorcaserin, however, will not be faced with a similar risk.

Yet experts and health professionals have questioned a number of aspects of the trial — including Jeans. Firstly, she highlights that the amount of weight lost was underwhelming. More than 12,000 overweight or obese participants were given either a dose of lorcaserin or a placebo, and over a period of 40 months those given lorcaserin shed an average of 4.2 kg of weight compared to 1.4 kg in the placebo group. As Jeans points out, this is actually a fairly small amount considering participants were monitored for over three years — also by the end of the study, most people taking the drug were still in the overweight or obese category. And although there was a difference between the two groups, the group taking the drug lost on average just 2.8 kg (less than half a stone) more than the placebo group.

 Secondly, a number of other factors could have been at play aside from the drug itself. Participants were given a weight management programme which involved a tailored exercise plan and unlimited access to a dietitian over the phone.

Other questions also remain unanswered. For example, the group was only trialled for a 40-month period, so it’s impossible to guarantee the drug’s safety long-term, or predict what will happen when people stop the drug.

 Lorcaserin was approved in 2012 by the Food and Drug Administration (FDA) in the USA, where it has been available for several years under the name Belviq. But it has not yet been approved for use in Europe — and some think it should stay this way, as many experts believe that weight management should start with lifestyle changes.

On its website, the NHS states: “ changes such as altering diet and exercise should be the priority when trying to lose weight, rather than relying on a drug for treatment”.

Side effects

With any medication there is also the question of side effects. While lorcaserin has been deemed safe in terms of cardiovascular risks, around seven per cent of trial participants gave up taking the drug because of dizziness, fatigue, diarrhoea, nausea or headaches. Suicidal thoughts were also twice as common in the drug group as in the placebo group.

As Jeans says: “All medication will have some effect on the body — if you put something in to artificially create balance, you’re going to knock something out somewhere else.” 

Take orlistat for instance. The only slimming pill available on the NHS, but also available over-the-counter as alli, orlistat works by preventing the body from absorbing fat. Yet this comes at a price: when people taking the drug do eat foods containing fat, there can be distressing side effects including abdominal pain, anxiety, flatulence, faecal incontinence and oily stools.  Not only are these side effects unpleasant, but could they also impact health?

“The problem with something like orlistat is you are preventing absorption of all fats, but some fats are important for our bodies,” says Jeans.

“For example if we don’t have enough cholesterol we can’t make our sex hormones or our adrenal hormones, which are so important for how our body functions.”

...weight management is not just about eating less, it’s about eating better — and drugs can’t match up to the nutrition and natural goodness from healthy food

Essential fatty acids such as omega-3s, she says, also “help our body listen to insulin”. Reduced insulin sensitivity, she explains, means we are more likely to put on weight. “So it’s really not a long-term solution.”

Indeed the National Institute for Health and Care Excellence (NICE) lists contra-indications for orlistat as cholestasis and chronic malabsorption syndrome. Cholestasis is a condition in which bile cannot flow from the liver to the duodenum (part of the small intestine). Chronic malabsorption syndrome means that the digestive system does not absorb nutrients efficiently. Cautions also include “chronic kidney disease; may impair absorption of fat-soluble vitamins; volume depletion (fluid/electrolyte loss)”. It is for such reasons that any weight-loss aid should not be used without medical advice.

A spokesperson for GSK, which manufactures alli, said: “alli is a weight-loss aid for adults who are overweight with a BMI of 28 kg/m2 or more and should be used with a reduced calorie, lower fat diet. alli contains orlistat which has been widely studied in over 100 clinical trials and has a well-established safety and efficacy profile when used as directed. We strongly discourage inappropriate use of any medicine; people using alli should do so responsibly, following the dosage guidance provided and seeking advice from their pharmacist if they have any questions.”

However, as many are keen to stress, weight management is not just about eating less, it’s about eating better — and drugs can’t match up to the nutrition and natural goodness from healthy food.

“Often the reason people get problems with their weight in the first place is because they don’t prioritise their food,” says Jeans.

And fundamentally, while weight-loss pills might help trim a few inches off our waistline, they may not solve the problem long-term, or make us healthier. Many people struggling with their weight have a difficult relationship with food, and no drug (so far) is able to address the emotional issues attached to overeating.

This was demonstrated in a study published in the Journal of Health Psychology which looked at the effectiveness of orlistat.2 An 18-month follow-up of 10 subjects who had gained weight after taking orlistat found weight-gain was attributed to a series of problems that the drug could not address, including relationships or psychological and physical issues.

So whilst losing weight naturally is clearly preferable, could a drug like lorcaserin be a push in the right direction for those who are really struggling?

Professor Jason Halford, an obesity expert at the University of Liverpool, says it could be “a way for individuals to regain some control over their appetite” — if used as part of a broader weight management programme.

As it stands, there are no appetite suppressants available on the NHS, and Halford suggests prescribing something like lorcaserin to patients could be a way of bridging the “massive” gap between lifestyle changes and bariatric surgery.

He also points out that even modest weight-loss can be beneficial in preventing further diseases related to obesity — particularly diabetes. This is supported by a recent study published in The Lancet, which found lorcaserin reduced the risk of diabetes by 19 per cent in patients with pre-diabetes and induced diabetes remission in others.3

But Dr Emily Burns, head of research communications at Diabetes UK, says although the research shows potential, it’s not significant enough to warrant any changes in the way type 2 diabetes is treated.

“There’s still a long way to go before we understand if appetite suppressants could play a role... or who could benefit from taking them,” she says.

The bottom line is: while weight-loss pills could be a helping hand for some individuals, on a wider level we clearly need to do a lot more than introduce drug treatments to fight the growing obesity crisis.

As Jeans puts it: “We need a functional medicine approach. We need to look more deeply into the underlying causes instead of trying to find a quick fix solution — a quick fix for weight-loss doesn’t exist.”




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  1. Bohula E et al (2018). Cardiovascular safety of lorcaserin in overweight or obese patients. New England J of Med, 379: 1107-1117.
  2. Hollywood A & Ogden J (2014). Gaining weight after taking orlistat: A qualitative study of patients at 18-months follow-up. J of Health Psy, 21(5): 590-8.
  3. Bohula E et al (2018). Effect of Lorcaserin on prevention and remission of type 2 diabetes in overweight and obese patients. The Lancet, 10.1016/S0140-6736(18)32328-6.