GLP-1 medications such as semaglutide and tirzepatide have changed the way we approach weight management. For many people, these medications can significantly reduce appetite, support weight loss and improve aspects of metabolic health.
But there is an important part of the picture that can sometimes be overlooked: what you eat while taking a GLP-1 matters.
When your appetite is significantly reduced, eating less may feel like the goal — but eating too little or relying on a limited range of foods can make it harder to meet your body’s nutritional needs.
This is where working with a nutritionist can make a real difference.
GLP-1s Can Change the Way You Eat
GLP-1 medications work in part by reducing appetite and slowing gastric emptying. This can make it much easier to eat smaller portions and feel satisfied with less food.
For someone who has struggled with hunger, cravings or overeating, this can be incredibly helpful.
However, a reduced appetite can also mean that you simply don’t feel like eating enough.
You may find yourself skipping meals, eating very small portions or becoming less interested in foods you previously enjoyed. Some people also experience nausea, constipation, diarrhoea, reflux or other digestive symptoms, which can further reduce food intake.
The result can be a diet that is lower not only in calories, but also in protein, fibre, vitamins and minerals. Current nutrition guidance for people using GLP-1 therapies highlights the importance of maintaining nutritional adequacy rather than focusing solely on reducing calories.
Eating Less Doesn’t Always Mean Eating Better
When appetite is low, every meal becomes more important.
If you’re only eating a small amount, choosing foods that provide plenty of nutrition in a relatively small portion can help you get more from what you do eat.
Rather than simply asking:
“How little can I eat?”
we want to ask:
“How can I make the food I am eating as nourishing as possible?”
This means prioritising foods that provide protein, fibre, healthy fats and essential vitamins and minerals.
Protein Becomes Particularly Important
One of the key considerations during weight loss is maintaining muscle mass.
Weight loss involves changes in body composition, and some loss of lean mass can occur alongside fat loss. Research suggests that adequate protein intake and resistance exercise can help support the preservation of muscle during weight loss, including weight loss associated with incretin-based medications.
This is particularly important if your appetite has dropped significantly.
Instead of leaving protein until the end of the meal, we can make it a priority.
Good sources include:
- Eggs
- Fish and seafood
- Chicken and lean meat
- Greek yoghurt and cottage cheese
- Tofu and tempeh
- Lentils, beans and chickpeas
- Nuts and seeds
- Protein-rich smoothies where appropriate
The amount of protein you need is individual and depends on factors such as your age, body composition, activity levels and health history. A nutritionist can help determine an appropriate target for you.
Don’t Forget Fibre
Fibre is another important part of the diet — but it can become more difficult to consume when you’re eating significantly less.
Fibre supports digestive health, bowel regularity and the gut microbiome. However, suddenly increasing fibre while taking a GLP-1 medication isn’t necessarily the answer, particularly if you’re already experiencing bloating or constipation.
Instead, your nutritionist can help you gradually introduce the right types and amounts of fibre for your individual digestive tolerance.
Foods such as vegetables, berries, oats, legumes, chia seeds, flaxseeds and wholegrains can all contribute to your daily fibre intake.
And don’t forget fluids. Good hydration is particularly important if you’re experiencing constipation, vomiting or diarrhoea.
What About Vitamins and Minerals?
When you’re eating considerably less food, you’re also potentially consuming fewer vitamins and minerals.
This doesn’t mean that everyone taking a GLP-1 medication needs supplements.
It does mean that nutritional adequacy deserves some attention.
Depending on your diet, symptoms, medical history and individual risk factors, a nutritionist may identify areas where your intake could be improved or discuss whether nutritional testing is appropriate.
Emerging research has highlighted potential concerns around inadequate intake of nutrients such as iron, vitamin D, calcium and B vitamins during GLP-1 treatment, although more research is needed to understand the extent and causes of these nutritional issues.
Managing the Digestive Side Effects
Nausea, constipation, diarrhoea, reflux and changes in appetite are commonly reported with GLP-1 medications.
For some people, these symptoms are mild and temporary. For others, they can significantly affect what and how much they are able to eat.
A nutritionist can help you identify foods, meal sizes and eating patterns that are easier to tolerate.
For example, you may benefit from:
Smaller meals rather than large portions
Eating slowly and stopping when comfortably satisfied
Prioritising protein before filling up on other foods
Adjusting fat intake if high-fat meals worsen nausea or digestive discomfort
Choosing cooked vegetables rather than large amounts of raw vegetables if digestion is sensitive
Gradually increasing fibre when constipation is an issue
Maintaining adequate fluids throughout the day
The right approach will depend on your individual symptoms and tolerance.
A Nutritionist Can Help You Eat Enough — Without Undermining Your Goals
One of the biggest misconceptions around weight loss is that eating less is always better.
When appetite is already being suppressed by medication, the goal isn’t necessarily to keep reducing food intake.
Instead, the focus should be on quality, nutritional adequacy and sustainable habits.
A nutritionist can help you work out:
- How much protein you need
- How to build balanced meals when your appetite is small
- Which foods provide the most nutrition per mouthful
- How to maintain adequate fibre
- How to stay hydrated
- How to manage constipation or nausea
- How to maintain muscle while losing body fat
- Whether your diet may be putting you at risk of nutritional deficiencies
- How to adapt your diet as your medication and appetite change
And importantly, your nutrition plan should be individualised.
There is no single “GLP-1 diet” that works for everyone.
Don’t Forget Exercise — Particularly Strength Training
Nutrition is only one part of maintaining muscle during weight loss.
Resistance training is also an important part of a muscle-preservation strategy. Recent research supports combining adequate protein and resistance exercise with weight-loss treatment to help maintain lean mass and physical function.
This doesn’t mean you need to spend hours in the gym.
Your exercise program should be appropriate for your age, fitness level, health and experience. For some people, this might mean structured strength training; for others, it may begin with simple body-weight exercises and gradually progress.
Your healthcare team can help you determine what is appropriate.
GLP-1 Medication Is a Tool — Nutrition Builds the Foundation
GLP-1 medications can be a valuable tool for weight management and metabolic health.
But medication doesn’t replace the need for good nutrition.
In fact, the more your appetite is reduced, the more important it becomes to make the food you do eat count.
The aim shouldn’t simply be to watch the number on the scales go down. A successful approach to weight management should also consider muscle, strength, nutritional status, digestive health, energy levels and long-term eating habits.
Working with a nutritionist alongside your medical treatment can help you make sure you’re not simply eating less — you’re nourishing your body while you lose weight.
Taking a GLP-1? Let’s Make Sure You’re Getting the Nutrition Your Body Needs
If you’re taking a GLP-1 medication and finding that your appetite has changed, you’re struggling with digestive symptoms, or you’re simply unsure whether you’re eating enough of the right foods, personalised nutrition support can help.
Our nutrition team can work alongside your medical care to develop a practical, sustainable approach that supports nutritional adequacy, muscle health, digestive wellbeing and your long-term health goals.
Book a nutrition consultation to make sure your GLP-1 journey is supported by the right nutrition for your body.