01
The medicine turns down hunger
GLP-1 medicines copy a hormone that tells your brain you are full. That is all they do. They do not choose your food, and they do not keep your muscles strong.
Welcome to Slimr
Slimr: diet and GLP-1, in plain English.
Slimr is a free, independent UK guide for people losing weight with GLP-1 medicines like Mounjaro and Wegovy. No hype, no products to sell you, no miracle claims. Just the honest science on what to eat, how to move, and how to use these medicines well, so the weight you lose actually stays lost.
The simple version first
Three things to understand, in thirty seconds
02
Your diet decides what you lose
Eating less only works well if what you still eat is good. Protein and fibre protect your muscles and keep you full. That is why diet comes first on this site.
03
Movement keeps it off
Some strength work and a lot of walking is the difference between finishing lighter and weaker, or lighter and stronger. Walking is the unsung hero here.
Diet plus GLP-1: the heart of Slimr
Eating well while your appetite is smaller
This is the single most important idea on the site. GLP-1 medicines shrink how much you eat, which makes what you eat matter more, not less. When every meal has to count, these four evidence-backed patterns are the ones that pair best with treatment:
Strong evidence
Mediterranean diet
An eating pattern based on the traditional cuisines of countries bordering the Mediterranean Sea: mainly vegetables, fruit, pulses, wholegrains, nuts and olive oil, with moderate fish, dairy and poultry, and little red meat or processed food.
Read the full reviewModerate evidence
High-protein diet
Increases the proportion of energy from protein, commonly 25-35%, usually to improve fullness and preserve muscle during weight loss.
Read the full reviewModerate evidence
Volumetrics diet
Prioritises foods with low energy density, lots of water and fibre per calorie, allowing large, satisfying portions for fewer calories.
Read the full reviewStrong evidence
Plant-based diet
An umbrella pattern that puts plant foods at the centre of the plate without necessarily excluding meat, fish, eggs or dairy completely.
Read the full reviewNow the deeper detail
Mounjaro, Wegovy injection and Wegovy pills: how the three medicines compare
GLP-1 medicines mimic a hormone your gut releases after eating, the one that tells your brain you are full. Three products now lead the UK market, and their trial numbers are worth knowing side by side:
20.9%
Mounjaro (tirzepatide)
Mimics two hormones, GLP-1 and GIP. That is the average loss in SURMOUNT-1 at the top dose, the biggest result in any weight-loss trial so far.
14.9%
Wegovy injection (semaglutide 2.4 mg)
Average loss in STEP 1. The SELECT trial also found a 20% cut in heart attacks and strokes in people with existing heart disease.
13.6%
Wegovy pills (oral semaglutide 25 mg)
Approved by the MHRA on 11 June 2026, the first GLP-1 tablet licensed for UK weight loss. The OASIS 4 result is close to the injection, no needle involved.
T2D
Ozempic is a different licence
Same semaglutide molecule, but a lower dose and a completely different licence. It is approved for type 2 diabetes, not weight management.
One practical note: side effects, mainly nausea and digestive upset, are usually worst when the dose goes up. Smaller, lower-fat meals and good hydration genuinely help, which is one more reason the diet side of this guide matters from day one.
The movement side
Exercise is the other half of the prescription
The medicine creates the calorie deficit. Exercise decides what you lose it from, and what you get to keep. Our full guide covers every starting point, including chair-based options:
Weights and resistance
The non-negotiable on GLP-1s. Protects the muscle and bone that weight loss otherwise takes with it.
HIIT
Short, sharp intervals for maximum cardio benefit in minimum time, once you have a base.
Running
The classic aerobic engine-builder, and how to start without injuring yourself.
Walking, the hidden giant
The most underrated exercise in medicine. Free, joint-friendly, and astonishingly powerful for blood sugar, mood and keeping weight off.
Chair exercises
Real strength and cardio work for people with mobility issues, pain, or larger bodies starting out.
The big picture
GLP-1 plus healthy diet plus exercise: the combination the evidence supports
Put the physiology together and the picture is simple. Each lever does a different job, and the results multiply when you pull all three:
Lever 1
The medication
Creates the calorie deficit you could never quite hold on willpower alone. That is its whole job.
Lever 2
The diet
Makes that deficit nutritious instead of just small. Protein and fibre protect your muscle while the number drops.
Lever 3
The movement
Decides whether the weight you lose leaves you stronger or weaker, and it is what keeps the weight off afterwards.
The regain warning, straight from the trials
People who pull all three levers do not just lose more. They keep more of their muscle, push their blood pressure, blood sugar and cholesterol further in the right direction, and report feeling better while it happens. And there is a harder truth underneath: SURMOUNT-4 and the STEP 1 extension show what happens when treatment stops with nothing underneath it. The weight comes back. Habits built while appetite is low are the insurance policy. If you ever reduce or stop the medicine, the diet pattern and the walking routine are what remain. That is what using GLP-1 as a tool really means.
Beyond food
Vitamins, minerals and supplements, without the marketing
Most of the supplements industry runs on hope and packaging. A handful of products have real science behind them, a few situations genuinely call for them (vitamin D in a UK winter, B12 if you are vegan, folic acid in early pregnancy), and a lot of the rest is expensive noise. We sorted the honest science from the sales pitch:
Vitamins, honestly
The three or four worth taking in the UK, and the megadoses to skip.
Read the vitamin guideMinerals, honestly
Iron, magnesium, zinc and friends: when they help, when they are a waste of money.
Read the mineral guideSupplements that work (and the rest)
Creatine has real trials behind it. Detox teas and fat burners do not. MHRA warnings included.
Read the supplement guideGLP-1 patches: the truth
They are everywhere on social media. They are also nonsense, and here is the science of why.
Read the exposéThe UK safety net
Who actually checks what
Six real organisations stand between you and the cowboys. We explain what each one does, with direct links, on our regulators and Yellow Card page.
GPhCRegisters every legitimate UK pharmacy and pharmacist. If a dispensing pharmacy is not on the GPhC register, walk away.
MHRALicenses medicines in the UK and takes action against illegal sellers. Approved the Wegovy pill on 11 June 2026.
ASAPolices advertising claims. If a supplement or diet ad promises miracles, the ASA is who can ban it.
CQCInspects and rates health services in England, including online clinics and prescribing services.
NICEDecides which treatments are evidence-based and cost-effective enough for the NHS.
Yellow CardThe public reporting system for side effects. Anyone can report a suspected reaction to a medicine or supplement.
Key studies behind this page
We link the actual research, not press releases. These are the papers and reviews the numbers on this page come from.
- SURMOUNT-1 trial: Jastreboff et al., New England Journal of Medicine, 2022. Tirzepatide led to up to 20.9% average weight loss at 72 weeks on the 15 mg dose.
- STEP 1 trial: Wilding et al., New England Journal of Medicine, 2021. Semaglutide 2.4 mg led to 14.9% average weight loss at 68 weeks against 2.4% with placebo.
- OASIS 4 trial, 2025. Once-daily oral semaglutide 25 mg produced 13.6% average weight loss at 64 weeks against 2.2% with placebo, and around one in three adherent participants lost 20% or more.
- SELECT trial: Lincoff et al., New England Journal of Medicine, 2023. Semaglutide 2.4 mg cut major cardiovascular events by 20% in people with existing heart disease and overweight or obesity.
- SURMOUNT-4 trial: Aronne et al., JAMA, 2024. People who stopped tirzepatide after 36 weeks regained about 14% of their weight within a year, while those who continued kept losing.
- STEP 1 extension: Wilding et al., Diabetes, Obesity and Metabolism, 2022. One year after stopping semaglutide, participants had regained about two-thirds of the weight they had lost.
Questions people actually ask
Can I use a GLP-1 medication and follow a diet at the same time?
Yes, and that is exactly how these medicines are meant to be used. Mounjaro, the Wegovy injection and the new Wegovy pills are all licensed for use alongside a reduced-calorie diet and more physical activity, not instead of them. The medicine turns down your appetite. A decent diet makes sure the weight you lose is mostly fat, not muscle, and that smaller portions still give you the protein, fibre and micronutrients you need.
Which diet works best with GLP-1 medication?
There is no official "GLP-1 diet", but the patterns that pair best share three traits: plenty of protein to protect muscle, plenty of fibre to keep you regular and full, and minimally processed food so a smaller appetite still covers your nutritional bases. Mediterranean-style eating, high-protein approaches and volumetrics-style eating all fit that brief. Our reviews grade all 77 options on evidence, cost, risk and who should avoid them, so you can pick one with your prescriber.
Do I still need to exercise if the medication is working?
Yes, and this is the bit people skip at their peril. In the STEP 1 body-composition substudy, nearly 40% of the weight lost on semaglutide was lean tissue rather than fat. Muscle is your metabolism, your balance and your bone bank. Two or three short resistance sessions a week, plus as much walking as you can fit in, is the difference between finishing treatment lighter and finishing it lighter, stronger and healthier.
What is the difference between Ozempic, Wegovy and the Wegovy pill?
All three contain semaglutide, but they are different products with different doses and different licences. Ozempic is a weekly injection licensed for type 2 diabetes at doses up to 1 mg. The Wegovy injection is the same molecule at a higher dose, 2.4 mg weekly, licensed for weight management. The Wegovy pill is a daily 25 mg tablet, approved by the MHRA on 11 June 2026 as the first oral GLP-1 licensed for weight loss in the UK. Same ingredient, different dose, different licence.
Is it safe to buy GLP-1 medication online in the UK?
It can be, if you go through a regulated route. Use a UK service that carries out a genuine clinical assessment and dispenses through a pharmacy registered with the General Pharmaceutical Council (GPhC), and check that pharmacy on the GPhC register yourself. Never buy from social media sellers, marketplaces or messaging apps. Counterfeit weight-loss pens have put people in UK hospitals. Checked lists of legitimate providers exist for Mounjaro (monj.co.uk), the Wegovy injection (igovy.co.uk) and Wegovy pills (ogovy.co.uk).
What happens when I stop taking a GLP-1 medication?
The honest answer from the trials: the weight tends to come back. In SURMOUNT-4, people who stopped tirzepatide regained about 14% within a year, and in the STEP 1 extension people regained about two-thirds of their loss within a year of stopping semaglutide. That is why the habits matter so much. If you build a diet you enjoy and a walking and strength routine while your appetite is low, those stay with you whatever happens to the prescription.
How much does the Wegovy pill cost in the UK, and is it on the NHS?
Privately, most UK providers charge between about £99 and £270 a month depending on the dose, and many discount the first month by £30 to £50. There is no official list price, so comparing providers is worth real money. On the NHS, not yet: funding depends on a separate NICE appraisal that is still running, and realistic NHS availability is 2027 or 2028 with strict criteria. The checked list at ogovy.co.uk tracks which GPhC-registered pharmacies genuinely stock the pill.