GLP-1. There's no escaping it right now. The weight loss aid, originally created as a type 2 diabetes medication, is everywhere. It's been hailed as the antidote to the obesity epidemic. But is it?
And will it simply become an alternative to a healthy diet and regular exercise if users aren’t taught healthy habits alongside its use?
This article walks you through what the research actually says, where the medication genuinely helps, where the risks sit, and what to put in place around it so the results last.
As a Registered Nutritional Therapist, I sit with people every week who are weighing up the jab, already on it, or wondering how to come off without regaining everything. If you’d rather not work that out alone, you can book a free 20-minute call and we’ll talk through where you are and what would help next.
The obesity statistics are alarming. Since 1993 the proportion of adults in England who are overweight or obese has risen from 52.9% to 64.3%, and the proportion who are obese has risen from 14.9% to 28.0%.
Higher body weight can increase the risk of a heart attack, stroke, type 2 diabetes, some cancers, arthritis, respiratory conditions and reflux and gallbladder conditions. For some, it can also reduce overall quality of life, with or without other medical issues.
One thing is clear: GLP-1 is the subject of much debate.
So, are GLP-1 injections the answer? Let’s look at the research so we can weigh up the pros and cons.
A quick overview of how GLP-1 works
GLP-1 medications might be everywhere right now (you might recognise them under brand names like Ozempic and Wegovy), but just in case you aren’t familiar with how they work, here’s a primer.
GLP-1 agonists like Ozempic and Wegovy are administered via a weekly injection to the abdomen, using a medical pen with a small hidden needle.
They mimic the action of the signal ligand by binding to and activating a receptor in the hypothalamus. In plain language? GLP-1s help regulate appetite and blood sugar by essentially tricking the body into thinking it’s full and satisfied.
This triggers several processes that can aid weight loss:
- Enhances insulin secretion when needed. Insulin is the hormone that moves sugar out of the bloodstream and into the cells where it can be used for energy.
- Inhibits glucagon (store sugar) secretion from the liver. This helps to keep blood sugars down, and may even improve liver damage in cases of MASLD (formerly known as NAFLD, non-alcoholic fatty liver disease).
- Slows the release of food from the stomach, increasing the feeling of ‘fuller for longer’ to prevent snacking and overeating at meals.
- Aids satiety signalling to the brain. Loss of that signal can be down to leptin insufficiency or resistance.
What about Mounjaro?
Mounjaro has a dual-action effect compared to Wegovy and Ozempic, with the addition of GIP, glucose-dependant insulinotropic polypeptide. The addition of GIP in Mounjaro further increases insulin release and improves insulin sensitivity. The dual-action effect has been shown to increase the effectiveness, but in some cases, the side effects too.
We’ve covered the medication side in more detail in our guide to GLP-1 drugs (Ozempic, Wegovy and Mounjaro) if you want a head-to-head before deciding.
Natural GLP-1
An important point to note is that GLP-1 is a natural hormone produced by our bodies. It’s essential for regulating blood sugar, appetite and digestion.
For the body to create enough GLP-1, we need to chew food properly to trigger its release, and have a healthy gallbladder and healthy gastric acid. Maintaining a healthy microbiome also matters, because gut bacteria play a significant role in digestion and hormone regulation, including GLP-1. If you’d like the full picture on how to support your own GLP-1 naturally, we’ve written a dedicated piece on it here.
Potential benefits of GLP-1
Let’s start with the positives. The outcomes of GLP-1 use for weight loss beyond two years are still unknown, so there’s a lot we don’t yet know about it as a long-term weight loss tool. Type 2 diabetes use beyond two years, however, is known and approved, so long-term expectations can be hypothesised from that data.
So what are the known benefits?
Weight loss is the obvious one. In a 2024 trial, participants receiving weekly doses of semaglutide lost an average of 15.2% of their body weight over 104 weeks.
GLP-1 agonists are also linked with reduced blood sugar. A 2022 review showed they reduced HbA1c, a measure of average blood sugar, by approximately 1.0 to 1.5% compared with placebo.
That kind of shift can pull a person from a diabetic to a pre-diabetic range, or out of the danger zone entirely, which is why we see GLP-1s as part of broader conversations around insulin resistance and pre-diabetes.
There may also be a correlation between GLP-1 use and improved cardiovascular outcomes. A large-scale meta-analysis of cardiovascular trials found these medications effectively lowered HbA1c and systolic blood pressure. Research has also shown that GLP-1 receptor agonists significantly reduce the risk of major adverse cardiovascular events (MACE), which include heart attack, stroke and cardiovascular-related death.
GLP-1 agonists may have anti-inflammatory benefits, too. Research suggests they reduce systemic inflammation by lowering pro-inflammatory cytokines and oxidative stress.
Other potential benefits
- Improved dyslipidaemia (cholesterol)
- Reduced risk of CVD
- Reduced all-cause mortality
- Improvement of blood circulation
- Increased nitric oxide level
- Inhibition of procoagulant factors
- Reduced risk of liver and/or kidney disease
- Potentially reduced risk of some cancers (but not all)
There is also potential support for polycystic ovarian syndrome (PCOS), where insulin resistance is a driving factor.
This is the part of the picture most patients don’t get told: the medication isn’t only doing weight work, it’s doing metabolic work, which is why we treat blood sugar, cholesterol and blood pressure as a single problem in clinic, not three separate ones.
Potential risks of GLP-1
Now for the risks. There is a lot to cover.
First up, digestive issues: nausea, vomiting, diarrhoea and/or constipation, and loss of appetite. (You might be thinking, ‘It’s meant to make you lose your appetite,’ but we’re talking to a level that makes meal times and food potentially unenjoyable.)
Nausea and vomiting are thought to occur in 40 to 70% of users. If you have a tendency towards slow bowel motility (going less than once a day), there is every chance you’ll be reduced to once per week, posing alarming risks and a huge amount of discomfort.
Low blood sugar is another known risk. The drugs work by stimulating insulin release in response to elevated blood sugar, and that can lead to an excessive reduction and the risk of fainting. We need some sugar in our blood at all times. Excessive amounts are a problem; so are low ones. This is an especially concerning side effect for people with diabetes who are already managing delicate blood sugar levels.
There’s no doubt that GLP-1 can aid weight loss. But not all weight loss is good, and that’s the part of this conversation that gets skipped most often. Research shows that GLP-1 drugs can also cause a loss of muscle mass. Studies have shown that approximately 25% to 39% of the total weight lost using these drugs may come from fat-free mass.
Muscle tissue is metabolically active. It burns more calories, even at rest. When you lose muscle mass, your basal metabolic rate (BMR) drops, which makes the weight loss harder to hold and the regain easier to trigger. In later life, low muscle mass also contributes to frailty, falls and worsening insulin sensitivity. It’s why we make protein, resistance training and muscle preservation non-negotiables on a GLP-1, not optional extras.
Muscle loss shows on the scales as a reduction in your relationship to gravity, your weight, but it is not the way to lose weight. Unless you have a DEXA scan or you’re regularly building strength in the gym, you won’t truly know whether you’ve dropped fat mass or muscle mass. Not all weight loss is good.
Tellingly, rebound weight gain is common when users discontinue the drug, with approximately two thirds of the weight evidenced to return.
It’s a clear sign that with or without GLP-1 medications, education and behaviour change must come first. Learning how to eat well and live a healthy lifestyle is key to losing weight, keeping it off and improving overall quality of life.
If this is where you are right now, considering the jab, on it but worried about side effects, or planning to come off, our GLP-1 nutrition support service is built for exactly this stage. We help you preserve muscle, manage side effects and put the long-term foundations in before the medication does its full course.
Other potential risks
- GERD, gastritis, abdominal distension
- Gallstones
- Fatigue
- Hair loss
- Infections
- Headaches, dizziness
- Mental health concerns
- Mild tachycardia (increased heart rate)
- Allergic reactions
- Pancreatitis
- Acute kidney injury
- Worsening of diabetes-related retinopathy
It is not recommended for individuals with a history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2.
The gene that can make GLP-1 ineffective
Another thing to consider in the GLP-1 argument? The TCF7L2 gene.
You might not have heard of it, but the TCF7L2 gene is strongly associated with the development of type 2 diabetes and can make GLP-1 less effective. This gene is involved in the regulation of insulin secretion and glucose homeostasis, which directly affects how the body responds to GLP-1 signalling.
In short, if TCF7L2 is downregulated, your benefit from GLP-1 agonists will be too. We see this every week in clinic: someone has been on the jab for months, the scale isn’t moving, and there’s no obvious reason. Functional testing often surfaces what generic prescribing can’t. A wellness check is usually the place to start.
A healthier alternative?
In an ideal world, we wouldn’t need GLP-1 drugs to tackle obesity. We’d manage weight through healthy lifestyle habits. Unfortunately, food misinformation and clever marketing have made that difficult.
Japan is a positive example of what can be achieved with a balanced approach to nutrition.
In Japan, just 4.5% of the population is obese, and obesity rates are expected to shrink by 0.6% per year. (Quick comparison to the stats above: in England, the proportion of adults who are now obese is 28%.)
The core feature of Japanese cuisine is simplicity, drawing out the innate flavour of the fish, vegetables and rice (yes, rice, which is usually a no-go for people with blood sugar issues). Eating until you’re 80% full is a concept that’s taught from childhood.
By law, every Japanese school has to employ a nutritionist to oversee meals and educate children and parents. The guidelines are no processed or frozen foods, no packed lunches. Japanese supermarkets look different, too, with fewer ultra-processed foods on the shelves.
What would our obesity statistics look like in the UK if we followed suit? Would there be a need for GLP-1s as a weight loss aid at all?
We can’t change UK food policy from a nutrition clinic, but we can give you the same toolkit: portion awareness, food noise reduction, and a way of eating that supports steady blood sugar. That’s the daily work of our blood sugar and insulin resistance programme.
What’s next?
It’s safe to say that GLP-1 agonists are here to stay. We don’t have a crystal ball, but we expect more data on long-term use as a weight loss tool, more headlines about risks, and possibly increased use among children.
There could be a drop in metabolic conditions, which would be positive. But could it come at a different price, with an increase in other conditions as a result of GLP-1 use?
So much remains unknown, and it remains a very personal decision.
What is certain, however, is the effectiveness of good nutrition. Eating a balanced, nutrient-rich diet remains one of the most reliable and sustainable methods for losing weight and keeping it off.
A multi-disciplinary support team is advisable to make long-term changes stick. At Integral Wellness, we support clients on GLP-1 to make the changes that hold once the medication stops. Our work is holistic: nutrition, lifestyle, movement, sleep, stress and mindset, so clients have a full set of tools to use every day. We’ve helped clients like Lou, who lost 44 kg and came off his medication, do exactly that.
Whichever stage of GLP-1 you’re at, there’s a next step here that fits
Considering the medication, already on it, or planning to come off? You don’t have to make the call alone.
Start with the science. Read our GLP-1 medication support guide to understand what these drugs do, what they don’t, and what to put in place around them.
Want a baseline before deciding on a programme? Book a wellness check and we’ll look at the markers that matter: muscle, blood sugars, insulin, lipids. Numbers first, plan second.
Ready for full one-to-one support? Our weight loss and GLP-1 nutrition programme is built for people who want a structured plan to lose weight, hold the loss, taper off the medication safely, or build metabolic resilience alongside it.
Not sure yet? Book a free 20-minute call and we’ll talk through where you are and what would actually help.
