For decades, the standard advice for people living with overweight and obesity has been simple: you need to “eat less and move more.”And people have been trying. About 45% of adults in England are actively attempting to lose weight at any given time (with women more likely than men). Yet, it doesn’t appear that all of that work is producing the results we’d hope for. As a population, weight continues to climb: the percentage of adults living with overweight and obesity has increased from 61.2% in 2015–16 to 64.5% in 2023–2024. If we look at the proportion of people living with obesity, it has almost doubled since the 1990s.
The reality is that long-term weight loss is hard for most people. Without continued, intensive support, over half of the weight lost is regained within two years. Over 80% is regained after five years.
“Eat less and move more” isn’t always easy.
What feels easy or hard is shaped by biology (e.g., hormones, appetite signalling), environment (e.g., food access, culture, work patterns) and personal history (eg lengthy history of weight struggle or fluctuations). Because of this, what could seem like just a simple, manageable tweak for one person can become a lifelong battle for another. For some people, the struggle may demand a significant amount of time, headspace and support, and still not deliver the results they hoped for.
Part of the problem is that we tend to underestimate how strongly biology shapes our behaviour. We often assume that if someone lives with 'genetic obesity', it’s because that person has a 'bad metabolism', which causes them to burn less energy and accumulate more fat. However, we now know that many of the genes linked with weight and obesity actually influence hunger and fullness signals. The most extreme cases are found in rare conditions where defects in genes (mutations) affect what’s called the leptin–MC4R pathway. The hunger signals for people affected by this are so intense that having the mutation leads unequivocally to early childhood obesity. For most people, however, these signals are more subtle. Their appetite is nudged upward, so they may feel a little hungrier and less satisfied after meals. And that's all it takes. Increased hunger leads to higher food consumption. And higher food consumption over time results in higher weight.
Let’s reframe the question.
Instead of asking, “Isn’t it easier to just eat less and move more?”, a better – and more important – question is:
"Can we make it easier to eat less and move more?"
And for the first time, we can answer that question unequivocally: yes, we can.
This is the context in which some people consider GLP-1 medicines – not as a shortcut, but as a medical tool that can help biology work with their efforts, alongside the tools they already have.
GLP-1s are not here to replace healthy habits – we use them to make them easier to follow. By reducing hunger and cravings and helping you feel full sooner, people naturally choose smaller portions and fewer snacks, making it much easier to achieve their goals. That’s the point: we align biology with intention so that your body and your goals are working together, not against one another.
Can GLP-1 medicines help you eat less?
Yes, since GLP-1 medications reduce hunger and cravings and help you feel full sooner, they can reduce how much you eat. People taking Wegovy (semaglutide) ate around 24% fewer calories in supervised eating tests than those given a placebo (a ”dummy” injection with no active medication). They also felt more in control around food and reported having fewer cravings, feeling fuller, and finding it easier to stop meals. These effects make the same advice – eating less – feel easier to follow day to day.
Can GLP-1 treatment help you move more?
Often indirectly, yes, since weight loss makes movement easier. People tend to become more active as pain, breathlessness, and low energy improve with weight loss. A study found that in people with obesity and knee osteoarthritis, once-weekly semaglutide improved pain and physical function over 68 weeks versus placebo. These are changes that naturally lower the barrier to being active.
But we also have early evidence that starting a GLP-1 medication may lead to an increase in activity. Those who began a GLP-1 treatment lost approximately 10% body weight and carried out around 31 more minutes of weekly physical activity than people not taking the medication, according to a 12-week study in which participants wore activity trackers.
Not everyone will see the same benefits, but for many, the effects of GLP-1 medications and the resulting weight loss make change feasible, because biology is finally working with them, not against them.
Are the side effects worth it? Balancing benefits, risks and tolerance?
Navigating a personal and delicate balance of potential ups and downs is part of any medical treatment. When deciding whether to begin a GLP-1 treatment, you need to weigh the benefits (e.g., improvements in blood sugar, weight, and heart risk) against the risks (e.g., side effects and potential complications), as well as your own tolerance to the medication (how you personally feel while on treatment). And that balance can change over time. If you are someone with a complicated family history of cardiovascular disease or a significant amount of weight to lose, the benefits are especially clear. But that needs to be weighed up against the possibility of experiencing side effects and requiring dose adjustments or significant changes to your diet to tolerate the medication. Some will decide that GLP-1 medicines are just not for them, others may find that they are helpful at certain points of their weight loss journey and not others and reassess this over time with their doctor.
How common are side effects?
Most side effects impact the digestive system, so you might experience nausea, diarrhoea, vomiting or constipation. These side effects are common when starting the medication or when increasing the dose. Across several large studies of Wegovy for weight loss, these symptoms were more common with Wegovy than with placebo (73% of people on Wegovy reported them, compared with 47% of people on placebo). Most of them were mild-to-moderate in nature and settled as the body adjusted to the medication. Nausea typically settled within about a week, diarrhoea in a few days, and vomiting in a couple of days. Constipation was the side effect that tended to last the longest, but it also eased after a few weeks. Importantly, roughly 1 in 4 people had no stomach or gut symptoms at all. Digestive side effects are comparable with Mounjaro, but local injection side effects (such as redness or itching) are more common than in Wegovy users (up to 8.6 % vs. 0.3%).
Treatment for weight loss may also result in hair loss. In Wegovy studies, hair loss was reported in 2.5% of people taking Wegovy 2.4 mg, compared with 1.0% on placebo. The hair loss was mostly mild in these studies, and most people recovered while they were still on treatment. This side effect may be related to the extent of weight loss rather than the medication itself, as it was more common in those who dropped at least 20% of their body weight. It is well known that significant weight loss and restrictive dieting are triggers for a type of temporary hair loss called telogen effluvium, but regrowth is generally expected once the trigger settles.
How many people stop because of side effects?
In the same studies, about 4.3% of people stopped the GLP-1 treatment due to these symptoms, and about 12.5% needed a temporary pause or dose reduction to manage them. In a longer 2-year study, these side effects were still common, but as seen before, they were mild-to-moderate and temporary, with 3.9% stopping because of the digestive symptoms (versus 0.7% on placebo).
Can people feel better on GLP-1 treatment?
Many people do! Researchers used questionnaires to capture how people felt and function in daily life while they were part of the studies. What they found is that more people on Wegovy reported noticeable improvements in how easily they could move or manage day-to-day tasks compared with the placebo.
In another study, about 50% of people on Wegovy reported a meaningful improvement in everyday physical function compared with about 25% of people on a placebo. Around 40% of people taking Wegovy improved in ‘everyday physical tasks’, such as bending, standing more comfortably, walking further or faster, or feeling less breathless. In the placebo group, this improvement was seen in about 20% of people.
Bringing it back to the original question...
So, we were asking:
Why do people take GLP-1 medicines when side effects can be tough?
The answer is that people take GLP-1 medicines because they help them achieve their goals. We know that changing behaviour isn’t as simple as trying harder - it's much more about reducing the friction that's making that change difficult to make. Evidence tells us that people are more likely to make better choices when those choices are made easier for them.
GLP-1 medications work by reducing appetite, so they make it easier to ‘just eat less’. Suddenly, the healthy habits you were trying before are easier to achieve.
People may choose to start a GLP-1 treatment journey because they care about their health. It’s not a shortcut, and it isn’t for everyone; it’s a personal choice with a delicate balance of benefits, risks and how you feel on the medication. It’s a choice that's now available for people living with overweight and obesity, and one to discuss with a doctor in the context of their own personal biology and circumstances.
Key messages
- Let’s reframe the question: the important question is not “Isn’t it easier to just eat less and move more?” but “How can we make it easier?”
- Align biology with intention: GLP-1s can lower hunger and cravings, so healthy habits are easier to achieve
- Decide what’s right for you: weigh benefits, risks and tolerance with your care team, using regulated, prescribed treatment alongside lifestyle support.
Disclaimer: This article is for general information only and does not replace personalised medical advice. If you’re considering treatment, please contact our care team.