GLP-1 medications, including semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), deliver a powerful change to the appetite signal. But what your body does with that signal, whether it translates into steady results or stalls out, comes down to your gut health.
Nutrient deficiency, gut motility issues and other GLP-1 side effects are common, and a big part of preventing them also comes down to your gut microbiome and the short chain fatty acids it produces.
In this article:
- What the enteroendocrine system is, and why it decides how well GLP-1 medications work
- Why “food noise” can return around the nine to ten month mark
- The nutrient deficiency data every GLP-1 user should know
- Why the clinical trials included diet, exercise and counselling
- How GLP-1 and GIP medications affect gut motility and SIBO risk
- The nutrients most at risk of depletion
- Our protocol for offsetting side effects and supporting long-term results
What Is the Enteroendocrine System? (And Why It Matters for GLP-1 Users)
Your gut lining is home to hormone-producing cells called enteroendocrine cells. The most relevant of these are L-cells which release your body’s own natural GLP-1.
L-cells respond to two things:
- Food, particularly protein, glucose and long-chain fatty acids
- Short chain fatty acids, the metabolites your gut bacteria produce when they ferment fibre
(Gribble & Reimann, 2019)
Short Chain Fatty Acids and GLP-1 Signalling: The Microbiome Connection
Short chain fatty acids bind to receptors on L-cells (FFAR2 and FFAR3) and trigger further release of GLP-1 and PYY, the hormones responsible for satiety (Tolhurst et al., 2012; Everard & Cani, 2014).
This means:
- A well-fed, diverse microbiome producing plenty of short chain fatty acids works with your GLP-1 medication
- A depleted, low-diversity microbiome is working against the very system the medication relies on
GLP-1 medications deliver a synthetic version of a signal your body already knows how to make. The prescription does its job. Whether that signal gets translated into steady appetite regulation, stable blood sugar and genuine metabolic change depends on the gut it’s landing in.
Food Noise on GLP-1: Why It Can Return and Are You Prepared?
One of the most reported benefits of GLP-1 therapy is the quieting of “food noise”, the constant background chatter about food and cravings.
Researchers describe this as the dynamic phase of treatment: appetite suppression, early fullness and reduced food preoccupation are strongest here (Chong et al., 2026).
The Stable Phase: When GLP-1 Appetite Suppression Starts to Fade
As treatment moves into the stable phase, where weight loss plateaus and the body adjusts, appetite suppression tends to diminish for many people (Chong et al., 2026).
In our clinic, this is often the point clients describe food noise and cravings returning, sometimes as early as nine to ten months into treatment.
It isn’t a sign the medication has stopped working. It’s a known pattern, and one you can prepare for rather than be blindsided by.
GLP-1 Nutrient Deficiency Statistics
A large US claims analysis followed 461,382 adults newly prescribed GLP-1 receptor agonists (Butsch et al., 2025). The findings:
- 12.7% had a diagnosed nutritional deficiency within 6 months
- 22.4% had a diagnosed nutritional deficiency within 12 months
- Vitamin D deficiency was the most common finding, followed by thiamine, other B vitamins and nutritional anaemia
We’re guessing they’re the ones not seeing a naturopath.
Did You Know? GLP-1 Clinical Trials Included Diet, Exercise and Counselling
The major clinical trials behind semaglutide and tirzepatide built lifestyle support into the study design, not as an add-on, but as part of the protocol:
- STEP 1 (semaglutide): participants received counselling for calorie reduction and physical activity throughout the 68-week trial (Wilding et al., 2021)
- SURMOUNT-1 (tirzepatide): participants received regular sessions with a dietitian or qualified health professional, targeting a 500-calorie daily deficit and at least 150 minutes of activity per week (Jastreboff et al., 2022)
The medication was never studied, or approved, on its own.
If you’re on a GLP-1 or GIP medication and want the best long-term results, a monthly check-in is advisable. Chat to us about how we can support you.
GLP-1 and GIP Side Effects: How These Medications Affect Your Gut
GLP-1 and SIBO: Increased Risk of Small Intestinal Bacterial Overgrowth
These medications work partly by slowing gastric emptying, so food stays in the small intestine for longer than usual.
- In one cohort of GLP-1 users tested for microbial overgrowth, over three-quarters returned a positive SIBO culture (Damianos et al., 2025)
- A separate global multicentre analysis confirmed a clear association between GLP-1 or dual GLP-1/GIP therapy and SIBO risk (Sun et al., 2025)
GLP-1 Constipation and Slowed Gut Motility
Constipation is another common GLP-1 side effect, largely driven by the same slowed motility.
- Establishing daily bowel movements before starting these medications matters
- A gut that’s already sluggish has less room to compensate once transit time slows further
Nutrient Depletions to Watch on GLP-1 and GIP Medications
- Protein
- Vitamin B12
- Zinc
- Magnesium
- Calcium and vitamin D
- Fluid and electrolytes
Left unaddressed, these depletions can show up as:
- Fatigue
- Hair loss
- Lower bone density over time
Our GLP-1 Gut Health Protocol at Gisborne Health Essentials
We follow a structured protocol with every client on a GLP-1 or GIP medication to:
- Offset side effects
- Support digestion
- Guide the diet and lifestyle changes that help you get the best outcome from your treatment
If you’re on one of these medications, or considering starting, book in for a check-in and let’s make sure your gut is doing its part.
FAQs
Does everyone on a GLP-1 medication develop a nutrient deficiency?
No. Research shows around 1 in 8 users develop a diagnosed deficiency within 6 months, rising to roughly 1 in 5 by 12 months (Butsch et al., 2025). Risk is higher without dietary support in place.
When does food noise typically return on a GLP-1 medication?
There’s no universal timeline, but many people notice a shift as treatment moves from the dynamic (weight loss) phase into the stable (maintenance) phase, in our clinic, often around nine to ten months (Chong et al., 2026).
Do I need a naturopath if I’m already seeing my GP or prescriber for my GLP-1 medication?
Your GP or prescriber manages the medication itself. A naturopath supports the gut health, nutrient status and digestive function that determine how well your body responds to it, work that complements, rather than replaces, medical care.
References
Butsch, W. S., Sulo, S., Chang, A. T., Kim, J. A., Kerr, K. W., Williams, D. R., Hegazi, R., Panchalingam, T., Goates, S., & Heymsfield, S. B. (2025). Nutritional deficiencies and muscle loss in adults with type 2 diabetes using GLP-1 receptor agonists: A retrospective observational study. Obesity Pillars, 15, Article 100186. https://doi.org/10.1016/j.obpill.2025.100186
Chong, M. C., Ko, T. Y. L., le Roux, P. L., & le Roux, C. W. (2026). Changes in eating behaviour during treatment with obesity medications. Clinical Obesity, 16(1), Article e70065. https://doi.org/10.1111/cob.70065
Damianos, J. A., Fredrick, T. W., Jin, M. F., Ospina-Velasquez, L., & Wang, X. J. (2025). GLP-1 receptor agonist use is associated with small intestinal bacterial overgrowth and intestinal methanogen overgrowth. Foregut: The Journal of the American Foregut Society, 5(4), 433–437. https://doi.org/10.1177/26345161251353437
Everard, A., & Cani, P. D. (2014). Gut microbiota and GLP-1. Reviews in Endocrine and Metabolic Disorders, 15(3), 189–196. https://doi.org/10.1007/s11154-014-9288-6
Gribble, F. M., & Reimann, F. (2019). Function and mechanisms of enteroendocrine cells and gut hormones in metabolism. Nature Reviews Endocrinology, 15(4), 226–237. https://doi.org/10.1038/s41574-019-0168-8
Jastreboff, A. M., Aronne, L. J., Ahmad, N. N., Wharton, S., Connery, L., Alves, B., Kiyosue, A., Zhang, S., Liu, B., Bunck, M. C., & Stefanski, A. (2022). Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine, 387(3), 205–216. https://doi.org/10.1056/NEJMoa2206038
Sun, Y., Veccia, D., Liu, B. D. X., Tse, W., Fass, R., & Song, G. (2025). Diagnostic evaluation of an increased risk of developing small intestinal bacterial overgrowth associated with glucagon-like peptide-1 (GLP-1) receptor agonists and dual GLP-1/GIP receptor agonists: A global retrospective multicenter cohort analysis. Diagnostics, 15(17), Article 2264. https://doi.org/10.3390/diagnostics15172264
Tolhurst, G., Heffron, H., Lam, Y. S., Parker, H. E., Habib, A. M., Diakogiannaki, E., Cameron, J., Grosse, J., Reimann, F., & Gribble, F. M. (2012). Short-chain fatty acids stimulate glucagon-like peptide-1 secretion via the G-protein-coupled receptor FFAR2. Diabetes, 61(2), 364–371. https://doi.org/10.2337/db11-1019
Wilding, J. P. H., Batterham, R. L., Calanna, S., Davies, M., Van Gaal, L. F., Lingvay, I., McGowan, B. M., Rosenstock, J., Tran, M. T. D., Wadden, T. A., Wharton, S., Yokote, K., Zeuthen, N., & Kushner, R. F. (2021). Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine, 384(11), 989–1002. https://doi.org/10.1056/NEJMoa2032183
