GLP-1 medications like semaglutide and tirzepatide have completely changed the landscape of obesity and type 2 diabetes treatment. For many people, they offer something that years of diets never could: meaningful, sustained weight loss and better blood sugar control.PubMed+1
A couple of weeks ago, I was happy to attend the annual Food As Medicine Conference hosted by the Temerity Faculty of Medicine, and the Department of Nutritional Sciences at University of Toronto. I have attended this conference every year for the last 9 years. Each year there is a different topic, and we are presented with the most up-to-date research in that area. This year, the conference topic was “Weight of Change – The Interplay of Nutrition, New Medicine and Stigma In Obesity”. While all presentations were enlightening, I was especially looking forward to our last presentation by Dr. Julia Lovshin. Dr Lovshin, Clinician Investigator and Assistant Professor of Medicine in the Division of Endocrinology and Metabolism, in the Temetry Department of Medicine at the University of Toronto. Dr. Lovshin is a staff Endocrinologist at Sunnybrook Health Sciences Centre in Toronto, where she specializes in diabetes clinical care. Dr. Lovshin’s presentation “GLP-1 Medications Unpacked: The Science, the Hype and the Fit” did not disappoint. I walked away with a clear understanding of the significant role that GLP-1 meds can play in obesity management and a keener understanding of why they are being more broadly prescribed for that purpose.
However, if you’re on one of these medications and dealing with constipation, nausea, bloating, or “sluggish” digestion, you are not alone.
Clinical trials and real-world studies consistently show that gastrointestinal symptoms—nausea, vomiting, diarrhea and constipation—are the most common side effects of GLP-1 receptor agonists.Harvard Health+3Nature+3PMC+3 In obesity trials in particular, constipation often shows up more frequently than it does in type 2 diabetes trials.Taylor & Francis Online+1
As a nutritionist who works every day with people struggling with IBS, chronic constipation, bloating and other functional digestive issues, I’m seeing more and more clients who are also using GLP-1 medications. They’re excited about their weight-loss progress—but frustrated that they now feel backed up, uncomfortable, or afraid to eat.
Let’s talk about why that happens—and what you can do to support your gut so you don’t have to choose between your metabolic health and your digestion.
How GLP-1 Medications Affect the Gut
GLP-1 receptor agonists (GLP-1 RAs) mimic a hormone your body naturally produces after you eat. They:
- help you feel fuller sooner
- slow down how quickly food leaves your stomach
- improve insulin secretion and blood sugar control
- support weight loss by reducing appetite and overall food intakeWiley Online Library
Those are powerful benefits. But that same mechanism—especially slower gastric emptying and changes in gut motility—is also part of why GI side effects are so common.
Research in people using GLP-1s for obesity shows:
- Nausea, vomiting, diarrhea and constipation are the leading side effects.Nature+1
- The risk of these symptoms typically increases with dose, especially during dose escalation.Nature+1
- Constipation in particular is reported more often in obesity trials than in diabetes trials.Taylor & Francis Online+1
In everyday language: your digestive system is being asked to slow down and adjust, while your eating patterns and appetite are changing—sometimes dramatically and quickly.
Why Constipation Is So Common on GLP-1s
If you’re on one of these medications and noticing constipation, there’s usually a layered explanation:
- Slower gut motility
GLP-1s slow gastric emptying and can affect gut movement further down the line. That longer “transit time” can mean drier, harder stools that are harder to pass. - You’re eating less overall
Less food = often less fibre and less bulk in the stool—especially if appetite suppression means you’re skipping meals or grazing. - Protein up, plants down
Many people (appropriately) increase protein while on GLP-1s, but don’t balance it with fibre-rich plant foods. Protein is important, but it doesn’t move through the gut the way fruits, veggies, legumes and whole grains do. - Hydration doesn’t “auto-adjust”
If your appetite is lower, you may naturally drink less, too. Less fluid means your colon pulls more water from your stool, making it harder and more difficult to pass. - Nervous system stress
Changing medications, rapid weight loss, worries about side effects, and long-standing stress all affect the gut–brain axis. A nervous system stuck in “fight or flight” tends to slow digestion and can worsen constipation.
So no—you’re not failing at your GLP-1 journey. Your gut is just being asked to function under very different conditions, and it needs support.
Gentle, Gut-Friendly Strategies to Ease Constipation
These are general strategies and not a substitute for personalized medical advice, but they’re often where I start with clients (in partnership with their prescribing physician):
1. Fibre—slowly and intentionally
Instead of suddenly piling on salads and bran, think slow, predictable increases in fibre:
- Aim to build toward ~25–30 g of fibre daily from food, if tolerated.
- Prioritize cooked veggies, peeled fruits, oats, chia, ground flax, and lentils/beans in small amounts.
- Increase by a little every few days, not all at once, to avoid worsening bloating.
2. Hydration that matches your new normal
If your portion sizes are smaller, you may not get as much fluid from food.
- Keep water or herbal tea nearby and sip regularly through the day.
- Aim for pale-yellow urine as a simple at-home gauge (unless otherwise directed by your doctor).
3. Don’t let meals disappear
Even if your appetite is lower, your gut still likes rhythm.
- Anchor your day around 2–3 predictable eating windows.
- At each, aim for: a source of protein + a source of fibre + some healthy fats.
- Tiny portions are fine—consistency matters more than size.
4. Movement as “gut physiotherapy”
You do not need intense workouts for bowel support—though many of my clients are already quite active.
- Gentle walking after meals can stimulate gut motility.
- On more constipated days, even 5–10 minutes of light movement can help.
5. A daily “bathroom appointment”
Your colon is trainable.
- Pick a consistent time—often after breakfast or a warm drink.
- Sit on the toilet, feet supported (a small stool can help), and give your body a chance without rushing or straining.
6. Talk openly with your prescriber
Severe constipation, abdominal pain, vomiting or inability to pass gas or stool need medical attention.Harvard Health+1
Sometimes the solution is as simple as:
- adjusting the dose or how quickly it’s increased
- adding or changing a laxative regimen
- ruling out other causes of symptoms
You should never feel like you have to “tough it out” alone.
Where My Work Fits In
This is exactly where functional, lifestyle-focused digestive support can make a difference.
In my practice and inside my Shift Your Gut Therapy™ program, I help people who are:
- on GLP-1 medications and suddenly dealing with constipation, bloating or reflux
- living with IBS or functional bowel disorders, now layered with GLP-1-related changes
- wanting to support their metabolic health and protect their long-term gut health
We look at:
- your specific bowel pattern and symptom history
- your eating rhythm and food choices now (not just “before the medication”)
- hydration, stress, sleep and movement patterns
- evidence-informed tools to support motility and comfort
GLP-1 medications can be a powerful tool—and so can understanding and supporting your digestion while you’re on them. You don’t have to choose between feeling better in your body and being able to go to the bathroom comfortably.
If you’re using a GLP-1 and recognize yourself in this story—constipation, bloating, or “my gut just hasn’t felt right since I started”—you’re exactly the kind of person I help.
If you’d like support navigating digestive symptoms while on a GLP-1 medication, you can book a complimentary Shift Your Gut Strategy Call to explore whether the Shift Your Gut Therapy approach is the right fit for you.
Note: Always consult with your doctor regarding the best medical support for you. This information is not intended to replace medical advice.