The use of weight loss injections to manage obesity has become big business in the UK and internationally.  This is due to the release of various weight loss injections (such as liraglutide, semaglutide, and tirzepatide) to the UK market since 2017.

As of March 2025, it was estimated that up to 1.5 million people in the UK were taking weight loss injections and an estimated  90% or more were purchasing these items privately.1,2  At a cost of approximately £100-£375 per month (depending on which medication is used and the dose), this can add up to approximately £4000 per year, just for the medication alone.  That doesn’t even include the cost of essential “wrap around” services, such as dietetic/nutrition input, a structured exercise program and cognitive behavioural therapy, which are all meant to accompany these injections.

Given the popularity and expense of weight loss injections, many health organisations and insurers are now questioning whether these medications represent a truly cost-effective approach to weight management.

In a landmark advisory statement published in July 2025, “Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society,” the opinion of these organisations is that weight loss injections are currently NOT considered to be a cost-effective approach to weight management.3

A paper in the Journal of the American Medical Association published in March 2025 came to the same conclusion.4

Both papers used quality-adjusted life-years (QALYs) as the basis for this conclusion. QALYs combine both the quantity and quality of life into a single value, allowing researchers to assess the overall benefit of a health intervention. Of course, using a different way to measure “cost-effectiveness” could lead to a different conclusion.

But how can this be?

The newest weight loss injections on the market, including semaglutide and tirzepatide, have been proven to help people lose up to 10-20% of their body weight, when combined with diet and lifestyle weight management strategies.  These injections can also help people with type 2 diabetes manage their blood glucose levels and reduce the rates of non-fatal heart attacks and strokes.  So how can these injections NOT be cost effective?

The joint advisory statement flagged three main areas of concern when it comes to cost-effectiveness:

1) Medication costs are extremely high.

The documents above were both published in the USA where the cost of the injections often range from $12 000 – $16 000 USD per year on average, which is almost double the price compared to the UK.3. Whether the slightly lower cost in the UK would change the conclusion around cost-effectiveness is not yet known.

There are currently only two UK studies available on cost-effectiveness and QALYs, but both have ties to the pharmaceutical companies who produce and sell these injections.5,6

2) Adherence rates at 12 months are low.

In spite of the potential ways that weight loss injections can improve health, it’s interesting that people tend not to continue using them for more than 2 years outside of a research setting.  The “adherence” rate, meaning the number of people who continue taking them after 1 year, is 33-50% (which means 50-67% of people stop taking them).  By year 2, only 15% of people are still taking them.3

The reasons that people discontinue are variable, and include:

• The high cost of the medication (if paying out-of-pocket).
• The gastrointestinal and side effects that people can experience as a result of the medication (such as nausea, vomiting, diarrhoea, constipation, fatigue and headaches).
• People not getting the weight loss results they want or their weight starting to plateau (usually at ~18 months).
• Supply shortages of the medication.
• Reduced food enjoyment and/or reduced quality of life.

3) There is a high risk of weight regain if someone stops taking the medication.

Sadly, when people stop using weight loss injections, research shows that they will regain at least 67% of the weight that they lost within the first year.3  This is part of the reason why some researchers suggest using these products long-term, but that comes at a high cost as well.7

So what is the answer?  Obesity is an incredible complex condition, with genetic and environmental, metabolic and medical factors all playing a role.  These factors are not always easy to change.  Clients recovering from major trauma face additional challenges, as body composition and metabolic rates are often altered following a serious injury. When combined with alterations to the person’s diet and physical activity level, this often results in 59-66% of clients after a brain injury or spinal cord injury becoming overweight or obese.8,9

There is no clear cost-effective way to manage obesity at this time.  For that reason, preventing, screening and intervening earlier may be our best hope at managing this complex condition in a cost-effective way.

Top 5 tips for minimising weight gain after a major trauma:

1)   Ensure clients can monitor their weight after hospital discharge.

Body weight will fluctuate significantly after a major trauma.  Initially, both muscle mass and weight are reduced significantly due to inflammation, lack of physical activity and/or an inadequate calorie or protein intake. However, near the end of someone’s hospital admission, their metabolic rate tends to stabilise at a lower level than what it was pre-injury.  This is when weight gain tends to start.

It’s essential that clients have access to stand-on scales, wheelchair scales or hoist scales (as required), in order to weigh themselves on at least a monthly basis to monitor what is happening. As wheelchair and hoist scales are generally not readily available at GP surgeries or in the community, clients who cannot stand unsupported will often need to purchase their own scales in order to monitor their weight post-injury.

For suggestions on scales,  go to our previous article on Weight monitoring for wheelchair users, bedbound and bariatric clients.

2) Case managers need to regularly ask clients if they have any concerns about their weight (and monitor clients directly if they lack mental capacity).

NICE guidelines on Weight Management: lifestyle services for overweight or obese clients, state that input from a multidisciplinary team (consisting of a dietitian, psychologist and physical activity instructor), may be of particular benefit to clients with a BMI over 30kg/m2 (or a BMI of 25-30kg/m2 for those from black and minority ethnic groups or those with other comorbidities such as type 2 diabetes).10  Earlier intervention is even better, but once clients reach a BMI of 30kg/m2 (especially after a major trauma), then referrals become mandatory.

3) Refer clients for intensive physiotherapy and personal training as early as possible.

After the initial trauma, many clients need to learn how to walk again and many need support with managing muscle spasticity as well.  The initial emphasis with physiotherapy is typically (and understandably) on improving independence and functional movement, but it’s worth adding activities which either increase calorie expenditure and/or increase strength and muscle-building as early in the regime as possible.  This can help clients manage their weight long-term.

4) Refer clients to a dietitian and psychologist as early as possible.

An unintentional 10% change in body weight after hospital discharge should prompt further investigation. If clients are aware of their weight gain (or loss) and are struggling to halt its progression, it’s worth having a holistic dietetic assessment to determine the root cause of the problem.  Sometimes the weight gain is because clients just don’t realise how much they need to reduce their food intake in order to adjust to their new post-injury metabolic rate.  However other times, the weight gain is a side effect of medication, or a consequence of unidentified sleep apnoea or issues with hormones or thyroid function.  Some clients will engage in emotional eating just to cope with the stress and anxiety of everything that has happened to them, or deal with the boredom of no longer being able to engage in the activities they used to enjoy.  Some clients after a brain injury may lack the mental capacity to understand the consequences of their food choices, and need decisions made in their best interest. All of these factors require professional input from a dietitian, and often a psychologist as well.

5) Ask the rest of the multidisciplinary team to review their activities to see if they are contributing to weight gain.

• Are GPs and psychiatrists considering a client’s weight when prescribing new medication?

• Is medication reviewed regularly to minimise those known to cause weight gain?  For more information on this topic, please see our article on “Medication-induced weight gain.”

• Are support workers trained and equipped to prepare nutritious meals rather than relying on takeaway or ready meals?

• Do therapy activities promote healthy cooking and eating habits (vs making cakes and cookies)?

• Are clients lacking capacity being assessed appropriately, with a dietitian overseeing decisions made in their best interest?

• Are social outings planned to include activities beyond food and drink (e.g. alternatives to frequent coffee shop visits)?

As you can see, there is a lot to consider when supporting clients who may be struggling with their weight.  Weight loss injections alone are clearly not the answer and they haven’t been found to be cost-effective either.

To refer a case management or litigation client for a comprehensive dietetic assessment, private blood tests and report, please contact Specialist Nutrition Rehab at 0121 384 7087 or info@specialistnutritionrehab.co.uk.

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