Frequently Asked Questions
Starting any new medication can feel daunting, and it is completely normal to have questions. Below we have compiled answers to the questions we hear most often from patients. If you have concerns that are not addressed here, please speak to your prescribing doctor or healthcare team.
ABOUT THE WEIGHT LOSS PRESCRIPTION
The Weight Loss Prescription is a comprehensive guide written by Dr Max Pemberton and Dr Courtney Raspin. It is designed to help you get the most out of GLP-1 medications like Wegovy and Mounjaro, and crucially, to help you keep the weight off once you stop taking them. The book is in two parts. The first part covers everything you need to know about obesity, metabolism, hunger, and how these medications work. The second part is a 12 session psychological programme that helps you change your relationship with food for good.
Here is the uncomfortable truth: research shows that a significant proportion of people on these medications regain some or all of their weight after stopping. One study found that participants regained about two thirds of their prior weight loss within 12 months of stopping treatment. The reason? They have not done the psychological work needed to change their relationship with food. The medication quiets the food noise and reduces your appetite, but it does not address the underlying reasons why you turned to food in the first place. Those patterns are still there, just masked by the medication. When you stop, they resurface. This book provides the missing piece: a step by step guide to making lasting changes while the medication gives you breathing space from the constant battle with food.
This is not a diet book. We do not tell you what to eat or give you meal plans and calorie counts. You probably already know plenty about nutrition. What most people lack is the emotional and psychological framework they need to change their relationship with food fundamentally. We developed this programme after years of working with patients struggling with their weight, and more recently, patients using GLP-1s who were struggling to stop their medication or had put weight back on after stopping it. The programme draws on evidence based psychological approaches including CBT (Cognitive Behavioural Therapy), Compassion Focused Therapy, Dialectical Behavioural Therapy, motivational interviewing and health psychology. We have taken the parts of these treatments that are most relevant and helpful for people with weight problems and combined them into a practical, accessible programme.
The 12 session programme covers a wide range of topics designed to help you understand and change your relationship with food. You will learn about emotional eating and why you turn to food for comfort. You will discover how your thoughts, feelings and behaviours are all connected using the Hot Cross Bun model. You will explore your eating patterns and learn to recognise your personal triggers. You will develop new coping strategies for difficult emotions that do not involve food. You will build sustainable habits using proven behaviour change techniques. You will learn how to manage cravings using techniques like urge surfing. You will work on body image, self-compassion, and silencing your inner critic. And you will create a personalised maintenance plan to keep the weight off for good.
Yes, and this is really important. The book is not like other books you might have read. It is not something you simply read from cover to cover and then put back on the shelf. The programme contains exercises that need to be done over and over, and tools that need to be practised, just as in a real psychotherapy session. The things covered need time and practice. You will likely find yourself going back to previous sessions to remind yourself what you need to practise and to go over things you are struggling with. That is exactly what happens in real therapy. No one can suddenly just do everything. Retraining your brain and developing new habits and attitudes takes time, so do not rush things. Go at your own pace, but please do not skip the exercises. Something you do not think is particularly relevant to you now might suddenly be very useful a few weeks or months down the line.
At first glance it will seem that each session is fairly short. It might only take you 15 minutes or so to read them. But the real work happens between sessions, when you are practising the techniques and completing the exercises in your daily life. We recommend spending at least a week on each session, though some people need longer on certain sessions, and that is absolutely fine. The maintenance phase of your medication, when you have reached your goal weight and reduced to a lower dose, is the ideal time to really focus on the programme. You should still be having some of the benefits of the medication while allowing yourself to feel some hunger and have more awareness of food. This is your consolidation window: a unique opportunity to build sustainable skills before you eventually stop the medication altogether.
Start now. Honestly, there is no better time than today. The medication you are taking is giving you a window of opportunity. It has quieted the food noise and given you space to think clearly about your relationship with food without being overwhelmed by cravings and constant thoughts about eating. Use this time wisely. The programme will rebuild your confidence through experience, not willpower. Together, the medication and the programme give you what you have never had before: a real chance to address the roots, not just the symptoms. The medication is temporary. The patterns you will change through the programme are permanent. So please, dust off the book, turn to Session 1, and begin. Your future self will thank you.
The Weight Loss Prescription by Dr Max Pemberton and Dr Courtney Raspin is available from all major bookshops and online retailers. You can also download the worksheets and exercises from this website to print off and use alongside the book.
GETTING STARTED WITH MEDICATION
GLP-1 medications work by mimicking a hormone that your body produces naturally called Glucagon-Like Peptide-1. When you eat, your intestines release this hormone, which sends signals to various parts of your body. The medication introduces levels that are higher than what your body typically produces, which has several effects: it stimulates your pancreas to release insulin at the right time, it slows down how quickly food moves through your digestive system (which helps you feel fuller for longer), and it acts on the brain to reduce appetite and those intrusive thoughts about food that many people experience.
Most people will start to see some weight loss within the first month of medication, but everyone is different. For some people it might take longer. Please avoid the temptation to compare your progress to that of friends or family who are on the medication. Every body responds differently. While some people start to lose weight on the lowest dose, others might need to reach the higher doses before they see significant results. This is not a failing and does not mean there is anything wrong with you. If you are worried about your progress, do speak to the person who is prescribing your medication.
Aim for slow, steady, consistent weight loss of around 0.5 to 1kg per week. This is not a crash diet. Taking time allows your body to adjust to the medication, limits the risk of side effects, and helps protect against muscle loss. If you are older, aim for nearer 0.5kg per week to ensure you maintain muscle mass. Rapid weight loss might seem appealing, but it increases the risk of problems like loose skin, nutritional deficiencies, and gallstones.
Absolutely not. Remember, everyone is different. Do not assume that just because one person has needed a certain dose that this dose will be right for you too. The aim is to find the dose that works for you, which might be much lower than the maximum. If you lose weight on a lower dose, you do not need to keep increasing. It is not a race to the top dose.
It is understandable that people are sometimes wary of new medications. The first thing to say is that GLP-1s are not new. While they have only recently been licensed for use in weight loss, this group of medications has been used by diabetic patients for many years. The first one was licensed in 2005, so they have been around for over 20 years. The first trials of semaglutide, the active drug in Wegovy, were in 2008. All medications that are licensed have to go through extensive, in depth trials and studies before they are approved to be prescribed to the public.
We have been surprised and saddened by some of the resistance patients have encountered from doctors, friends and family about the new medications. There is still a lot of stigma around obesity and some view these injections as cheating, as though those who are overweight need to be punished and to suffer in their pursuit of a healthy weight. Yet we do not apply this logic to other problems people have. No one says the same about nicotine replacement therapy for smokers, for example. Being on weight loss medication is not a quick fix. Patients still need to put in effort and work on ensuring long term change to their relationship with food. No one should feel shamed or made to feel guilty for trying to improve their health and wellbeing, however they choose to do it.
MANAGING SIDE EFFECTS
The most common side effects are gastrointestinal: nausea, constipation, diarrhoea, and abdominal discomfort. These tend to be worse in the first few weeks and when you increase your dose, and usually settle as your body adjusts to the medication. Think of it like moving to a new country: there is an adjustment period whilst your system adapts to new conditions, but most people settle in beautifully once they have acclimatised. Some people also experience fatigue, headaches, or a general feeling of being unwell early on. Some describe feeling as though they have mild flu for the first week or two. This usually improves.
The medication slows gastric emptying, meaning food moves more slowly through your digestive system. Whilst this contributes to the feelings of fullness that help with weight management, it also means your digestive system needs time to adjust to this new pace. Most side effects represent your body’s temporary adjustment period rather than signs that something is wrong. When you experience nausea or changes in bowel habits, you are not experiencing a malfunction. You are experiencing your body’s natural response to beneficial changes in how it processes food and regulates appetite.
Eat smaller, more frequent meals rather than large portions. Avoid fatty, greasy, or very rich foods, especially in the first few weeks. Eat slowly and stop as soon as you feel satisfied. Stay hydrated, but avoid drinking large amounts of fluid with meals. Some people find that ginger tea or peppermint helps settle the stomach. If nausea is severe or persistent, speak to your prescriber about adjusting your dose or the rate at which you are increasing it.
Stay well hydrated and ensure you are eating enough fibre. Gentle movement and walking can help keep things moving. If constipation becomes a problem, speak to your pharmacist about appropriate over the counter remedies. It is important not to ignore this side effect as severe constipation can cause problems, so do seek advice if simple measures are not helping.
Some people notice increased hair shedding when they lose weight rapidly. This is not unique to these medications. It happens with any significant weight loss. The hair loss usually stabilises as your weight loss reaches a plateau and then resolves as your body gets used to what is normal for you, though this can take around six months or so. Taking a skin, hair and nails supplement can help. This is another reason why aiming for slow and steady weight loss over a longer period is advised.
Very rarely, GLP-1 medications can cause inflammation of the pancreas (pancreatitis). Symptoms include severe, persistent abdominal pain that may radiate to the back, nausea, vomiting, and fever. This pain is typically different from the mild abdominal discomfort that can occur as a common side effect: it is severe and unrelenting. If you experience this, seek medical attention promptly. Severe allergic reactions are very rare but require immediate medical attention. Signs include difficulty breathing, swelling of the lips, tongue, face, or throat, difficulty swallowing, wheezing, rapid heartbeat, and sudden weakness or dizziness. If you experience any of these symptoms, seek emergency medical help immediately.
LIFESTYLE QUESTIONS
Alcohol affects the quality of sleep and disrupts various hormones in the body such as insulin, cortisol, and hormones involved in satiety, all of which have a knock on effect and make it harder to lose weight. It is also packed full of calories. Drinking too much while on weight loss injections also increases the risk of low blood glucose levels, so if you do drink, drink in moderation. Interestingly, an unexpected side effect that has been reported is that alcohol can lose its appeal because, in the same way it does for cakes and chocolate, the medication reduces the effect it has on the reward pathways of the brain.
Exercise is still crucial while on weight loss injections. Not only does it help minimise muscle loss and maximise results, but it is vital in ensuring you maintain the weight loss when you stop taking them. When the body is in calorie deficit, it tends to prioritise getting rid of muscle because muscle uses up a lot of energy. This is not helpful. The aim should be to build muscle in order to increase your basic metabolic rate, which will mean it is easier to lose weight and to maintain it. So, as well as a bit of cardio, we recommend focusing on weight training. Big, compound exercises like squats help to build large muscle groups. This can be daunting at first and you have to be mindful of injuries, so getting a personal trainer for a few months until you feel comfortable doing these kinds of exercises on your own is ideal.
Eating more protein not only helps people feel fuller for longer, but protein is also needed to build muscle mass. Make sure you are getting at least the recommended intake of protein with every meal and make sure your diet is not too carbohydrate heavy. Because you no longer feel as hungry, it is easy to skip meals but this risks low blood glucose levels which will make you feel tired and lacking in energy. Even if you are not hungry, your body still needs nutrition. We have seen patients who, while they lost weight, were eating only half a bacon cheeseburger for lunch and an ice cream for dinner. Will they keep this weight off after coming off GLP-1s? Absolutely not.
Sleep is essential in regulating the hormones that control appetite and metabolism. When you are tired, the brain’s reward pathways become more sensitive and you are more likely to find calorie dense foods appealing. Poor sleep leads to increased cravings for high calorie, high carbohydrate foods. Too little sleep also triggers a spike in cortisol which signals to your body to conserve energy, making it hard to lose weight. Sleep is also the time that muscle can heal, repair and grow. While everyone is different, most people need around 7 to 8 hours sleep a day. Those on weight loss medications might feel more tired as they are not eating as much, so it is important you get adequate sleep while on these drugs.
WOMEN’S HEALTH
Some women report changes to their periods when they start GLP-1 medications. Your cycle might become irregular, arriving earlier or later than usual, or the timing might become unpredictable. You might notice that your bleeding is heavier or lighter than normal. In some cases, periods might become less frequent or even stop altogether for a while. The medications themselves do not directly interfere with your hormones in the way that the contraceptive pill does. However, rapid weight loss affects your hormones. Fat cells produce and store hormones, particularly oestrogen. As you lose fat, these hormones are released, and your body needs time to adjust. If you notice significant changes, please have a chat with your doctor.
PCOS is closely linked with insulin resistance, and one of the things GLP-1 medications do is improve how your body responds to insulin. For many women with PCOS, this can be genuinely transformative. Better insulin sensitivity can help with weight loss (which is often really difficult with PCOS), and it can also help regulate your menstrual cycle. We have seen women with PCOS who have not had regular periods for years suddenly find that their cycles start to regulate when they are on these medications. Some women also notice improvements in other PCOS symptoms, like excess hair growth or acne, as their hormones start to balance out.
This is crucial information. If you have PCOS and you have been struggling with irregular periods or have not been ovulating regularly, these medications might restore your cycle and therefore alter your fertility. We are seeing what some people are calling Ozempic babies: women who thought they could not get pregnant suddenly finding themselves pregnant after starting these medications. As your insulin resistance improves and your weight decreases, your hormones can rebalance, and you might start ovulating again, sometimes without even realising it. If you are not planning to get pregnant, you need to use reliable contraception. Do not assume that because you have had irregular periods or have not been able to conceive before that you are safe now.
Even if you do not have PCOS, if you are of childbearing age and taking these medications, contraception is important. The weight loss facilitated by GLP-1s can improve fertility in some women, not just those with PCOS. If you are relying on hormonal contraception, be aware that the slower stomach emptying caused by these medications might affect how well oral contraceptives are absorbed. It is worth discussing with your doctor whether you need to switch to a different form of contraception or take additional precautions.
If you do want to get pregnant, you need to come off these medications first. We do not have enough research yet about their safety during pregnancy, so it is important to plan ahead and discuss this with your doctor.
GLP-1 medications work just as well for women going through menopause as they do for younger women. In fact, some recent research suggests they might work even better when combined with hormone replacement therapy (HRT). The two seem to work synergistically: the HRT helps reduce visceral fat and may improve sleep and mood, while the GLP-1 helps with appetite control and weight loss. Women naturally lose muscle mass during the menopause transition, and rapid weight loss can accelerate this, which is why resistance training becomes even more important if you are taking these medications during menopause.
STOPPING THE MEDICATION
These medications have a relatively long half life, meaning they stay in your system for a while. Skipping one dose will not see an immediate return to how things were before. But within a few days, as the drug levels drop, you will likely notice the familiar food noise creeping back: the cravings getting louder, the portion sizes harder to control, the mental preoccupation with food returning. Your reward pathways, which have been given a period of calm, start firing up again. For some people, this can feel quite dramatic after weeks or months of relative peace around food.
The truth is, most people do experience some weight regain when they stop taking GLP-1 medications. However, this is often because people have not taken the medication long enough or have not included a maintenance phase. We recommend that after reaching your goal weight, you reduce to a maintenance dose where your weight stays stable for about 12 months. This allows your body’s set point to adjust to a lower weight, so that your body starts to accept the lower weight as the new normal. It also allows the brain’s reward pathways time to recalibrate, meaning that people find they are less drawn to high calorie and sweet foods once they stop. Crucially, it gives you time to work through the psychological programme in this book, which addresses the underlying reasons why you struggled with food in the first place.
Do not rush this stage. We cannot emphasise this enough. This maintenance phase is arguably the most important phase of the entire process, and yet it is the one people are most tempted to skip because they are eager to prove they can manage without medication. The work you do in this phase is what separates temporary weight loss from lasting transformation. This is when you are teaching your body and brain that this new weight is safe, sustainable, and your new normal. This is also when you should be working through the programme in The Weight Loss Prescription, building the psychological skills and coping strategies you will need once the medication is no longer there to support you. Without doing this psychological work, the underlying causes of weight gain remain untouched, waiting to resurface.
The reduction should be gradual, typically stepping down by one dose level each month. Monitor your weight weekly during this time. You are looking for that sweet spot dose where your weight remains stable, you have some appetite regulation support from the medication, but you are also reconnecting with natural hunger and fullness signals. It is completely normal for your weight to bounce up and down by 1 to 2kg as your body adjusts to each new dose. What you are watching for is a sustained upward trend over several weeks, which might indicate you have reduced too far and need to go back up to the previous dose.
COMPARING MEDICATIONS
Based on clinical trial data, Mounjaro (tirzepatide) has a slight edge in terms of weight loss. People taking the highest dose of tirzepatide lost an average of around 20 per cent of their body weight over roughly eighteen months, compared to around 15 per cent with semaglutide (Wegovy). However, individual responses vary enormously. There were people in the semaglutide trials who lost 25 per cent or more, and people in the tirzepatide trials who lost less than 10 per cent. You might respond brilliantly to Wegovy and lose more weight than you would on Mounjaro. Or you might not tolerate Mounjaro well and cannot stay on the higher doses where the extra benefit is seen. Trial results give useful guidance but cannot predict your individual response.
Both can cause similar side effects, with nausea most commonly reported, particularly when starting treatment or increasing doses. Some report that Mounjaro causes slightly less nausea than Wegovy, possibly because the addition of GIP receptor activation does not slow gastric emptying quite as much. However, this is not universal. There is no reliable way to predict which you will tolerate better without trying them. Because Mounjaro is newer, we have slightly less long term safety data. Semaglutide has been available for diabetes treatment since 2017, whilst tirzepatide was only approved more recently. This does not mean Mounjaro is unsafe, just that we have a longer track record with semaglutide.
Internet message boards are full of people extolling the benefits of microdosing. People who are microdosing are falling into the trap of another crash diet. It is not good for their physical health and it is not good for their mental health. If your weight is not high enough to take a proper, prescribed treatment dose then this medication is not for you in the first place. If your weight is in the range that makes you eligible for this medication, then you will need a treatment dose. These are the doses that are licensed to be prescribed, and these are the doses that the evidence shows work.
A FINAL WORD
If you have questions or concerns that are not covered here, please do not hesitate to speak to your prescribing doctor or healthcare team. They are there to support you through any challenges you might experience. Remember that the goal is to find an approach that improves your health and wellbeing whilst being sustainable and tolerable.
For the comprehensive psychological programme that will help you keep the weight off for good, please see The Weight Loss Prescription by Dr Max Pemberton and Dr Courtney Raspin, available from all major bookshops and online retailers.