Ozempic, Wegovy and Mounjaro: A Complete Guide to GLP-1 Weight Loss Medications
By Dr Daniel Gordon • 27, Dec 2025
How Do GLP-1 Weight Loss Medications Work?
Ozempic, Wegovy and Mounjaro are GLP-1 weight loss medications increasingly used to treat obesity and metabolic disease. This article explores how they work, common side effects, safe rates of weight loss, and the importance of nutrition and medical supervision for sustainable results.
In a recent episode of my YouTube channel The Health Perspective, I sat down with Sara Hausmann, a registered dietitian with over 15 years of experience across the NHS and private practice, about the realities of taking GLP-1 medications in everyday life.
Sara has supported adults and children with obesity, diabetes, high blood pressure, high cholesterol, cancer, and disordered eating. She is one of the most thoughtful and patient-centred clinicians I know. As the use of GLP-1 medications has increased, a growing part of her work now involves helping patients lose weight safely while managing side effects and maintaining good nutrition.
Our conversation focused on what matters beyond the headlines. How these medications actually feel to take, the side effects people are often unprepared for, and the role that diet, exercise and proper medical oversight play in achieving results that last.
You can watch the full interview here:
This article is based on my interview with Sara Hausmann and brings together the most important clinical take-home messages from our discussion.
Let’s begin.
GLP-1 weight loss medications are not a shortcut
One of the most persistent myths around GLP-1 medications is that they are an easy option for people who haven’t tried hard enough.
In reality, most patients considering these treatments have spent years dieting, exercising, attending weight-loss programmes, and doing everything they were advised to do. We also know that genetics plays a major role in obesity, accounting for a significant proportion of risk.
For many people, GLP-1 medications do not replace effort. They allow effort to finally produce results. Used appropriately, they can lead to meaningful improvements in weight, blood sugar control, blood pressure, confidence, and overall quality of life.
GLP-1 dosing varies and higher doses are not always better
There is no single dose that works for everyone.
Some people respond extremely well to low doses, particularly if the main effect is reducing food noise and snacking. Others, especially those with significant insulin resistance, may need higher doses to achieve the same benefits.
From a health perspective generally a slower weight loss is safer. Sara recommends that around half a kilo per week is a sensible target for most people. Faster weight loss increases the risk of muscle loss, nutritional deficiencies, fatigue, and hair shedding.
Importantly, patients often have more control than they realise. Dose increases should be guided by effectiveness, side effects, and overall wellbeing, not pressure to reach a particular number.
Safe rates of weight loss reduce long-term health risks
Losing weight too quickly carries real risks.
Rapid weight loss is associated with loss of muscle mass, iron and vitamin deficiencies, fatigue, and hair loss. These issues are not inevitable, but they become more likely when weight drops too fast or nutrition is inadequate.
Slow, steady weight loss allows the body to adapt and makes it easier to preserve muscle, maintain energy levels, and support long-term metabolic health.
Common GLP-1 side effects and why they happen
Most side effects from GLP-1 medications relate directly to how they work. These drugs slow gastric emptying and reduce appetite, which is why gastrointestinal symptoms are common.
The most frequent side effects seen in practice include nausea, constipation, fatigue, acid reflux, and hair shedding linked to rapid weight loss.
Constipation is particularly common and often underestimated. Reduced food intake, slower gut movement, lower fibre intake, and reduced fluid consumption can all contribute.
Managing constipation on GLP-1 medications with diet
Dietary strategies should be the first step in managing constipation wherever possible.
Adequate hydration, daily gentle movement, and fibre-rich foods can make a significant difference. One simple, evidence-based example is kiwi fruit. Studies show that eating two kiwis a day can improve bowel regularity and significantly reduce reliance on laxatives. Eating the skin increases fibre intake further.
Other helpful options include flaxseed, chia seeds, berries, and regular meals rather than long periods without food.
Managing nausea and reflux while taking GLP-1 medications
Nausea is most likely when stomach emptying is slowed and large or high-fat meals are eaten.
Eating smaller amounts more regularly, reducing very fatty or heavily fried foods, and including some carbohydrate and protein at meals can help. Ginger, peppermint, fresh air, and sipping fluids little and often are also useful strategies.
For reflux symptoms, avoiding large evening meals, leaving several hours between eating and bedtime, staying upright after meals, and reducing spicy or high-fat foods can make a noticeable difference.
Nutrition and exercise remain essential on GLP-1 treatment
Reduced appetite does not mean nutrition becomes less important. In fact, it becomes more important.
Adequate protein intake helps preserve muscle mass during weight loss. Resistance or weight-bearing exercise, such as strength training or Pilates, plays a key role in maintaining strength and metabolic health.
Many people find that once their appetite and food noise are better controlled, it becomes easier to focus on these habits rather than harder.
Using medication to treat GLP-1 side effects is rarely the first answer
In general, lifestyle and dietary adjustments should come before adding more medication.
Many side effects settle with time, slower dose increases, or changes in eating patterns. If side effects are severe or persistent, this may be a sign that the dose is too high or that the medication may not be right for that individual.
The exception may be constipation, where gentle laxatives can sometimes be appropriate as part of a broader plan, but masking multiple side effects with additional drugs is rarely a good long-term solution.
Why GLP-1 medications need proper medical supervision
GLP-1 medications are powerful treatments that affect appetite, hydration, gut function, and metabolism. They are not benign supplements.
Patients need proper assessment, regular follow-up, and support from clinicians who understand how to use these medications safely. Many of the best outcomes seen in clinical trials occurred alongside structured dietary support and coaching, not medication alone.
Accessing these treatments without adequate medical oversight increases the risk of side effects, dehydration, nutritional deficiencies, and unnecessary harm.
Key takeaways for people considering GLP-1 medications
GLP-1 medications can be highly effective tools when used appropriately, but they are not a quick fix.
Slow, steady weight loss, adequate nutrition, resistance exercise, careful dose adjustments, and professional support are all essential.
When these elements come together, these treatments can support not just weight loss, but long-term health and wellbeing for the right people.
GLP-1 Weight Loss Medications: Frequently Asked Questions
What are GLP-1 weight loss medications?
GLP-1 medications are treatments that reduce appetite and slow digestion, helping people feel fuller for longer and lose weight more effectively.
Are GLP-1 medications safe?
When prescribed and monitored by a healthcare professional, GLP-1 medications are generally safe. Ongoing medical supervision is essential.
Do GLP-1 medications work without dieting?
They reduce appetite, but long-term success depends on good nutrition, regular meals, and healthy habits.
How quickly should you lose weight on GLP-1 medications?
Slow, steady weight loss is safest. Around half a kilo per week is a sensible target for most people.
What are the most common side effects of GLP-1 medications?
The most common side effects are nausea, constipation, fatigue, acid reflux, and reduced appetite.
Why do GLP-1 medications cause constipation?
They slow gut movement and reduce food and fluid intake, which can affect bowel regularity.
How can constipation be managed naturally on GLP-1 medications?
Adequate fluids, daily movement, and fibre-rich foods such as kiwi fruit and flaxseed can help.
Do GLP-1 medications cause nausea?
Nausea is common, especially early on or after dose increases, due to delayed stomach emptying.
How can nausea be reduced while taking GLP-1 medications?
Eating smaller meals more regularly, reducing high-fat foods, and avoiding large meals can help.
Do you need to exercise while on GLP-1 medications?
Yes. Resistance and weight-bearing exercise help preserve muscle and support long-term health.
Should side effects be treated with more medication?
Not usually. Dietary changes and dose adjustments are preferred before adding additional medication.
Can GLP-1 medications be prescribed online safely?
GLP-1 medications should ideally be prescribed with full medical assessment and follow-up, not without proper supervision.
Disclaimer
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