Caroline Gilmartin is a CNHC registered Naturopath, Principal and Owner of the Natural Healthcare College UK, and is currently Interim Chair of the Naturopathic Nutrition Association (NNA) who act as one of CNHC’s Verifying Organisations (VOs). In this blog post she looks at GLP-1 weight loss drugs and how naturopathic nutritional therapy can support people who are on or ending a period of taking weight loss drugs.
Glucagon-like peptide-1 (GLP-1) receptor agonists are increasingly being used in the management of obesity. Originally developed for glycaemic control in type 2 diabetes, these medications are now widely prescribed for weight loss due to their demonstrated effectiveness in reducing body weight (Wilding et al., 2021; Jastreboff et al., 2022).
These medications may be particularly beneficial for individuals with a body mass index (BMI) ≥30 kg/m², or ≥27 kg/m² in the presence of weight-related comorbidities such as type 2 diabetes, hypertension, or sleep apnoea. They may also offer additional benefit in specific circumstances, including individuals requiring weight reduction prior to surgery, those with limited mobility or who are unable to engage fully in physical activity.
For some individuals, the reduction in appetite and food-related preoccupation can provide an opportunity to initiate behavioural change and a sort of physiological “reset”.
However, from a naturopathic nutritional therapy perspective, their use raises important questions around nutrient intake, metabolic health, and whether the underlying drivers of weight gain are being addressed.
Real-world use and observations
From my own observations within local community groups, there has been a significant increase in the number of people accessing these medications privately or purchasing them online. Even within this relatively small sample, there appears to be a wide range of experiences.
Many individuals report being delighted with initial results, often noting reduced food expenditure (saving money) alongside weight loss. However, there are also frequent discussions around uncertainty with dosing, side effects, and how to maintain weight loss if they must stop, often citing the cost of private prescriptions. Also, what exactly people are purchasing on the internet is also a concern.
While all GLP-1 medications work through similar appetite-regulating mechanisms the do have distinct differences and risk profiles. Individual response and tolerance can vary substantially from person to person, and their use raises important considerations regarding nutritional status, lifestyle factors, and long-term outcomes.
Clinical trials have consistently demonstrated that GLP-1 receptor agonists can produce clinically meaningful weight loss. Average reductions of 5–18% body weight are commonly reported, with greater reductions observed in some individuals using newer agents such as tirzepatide (Jastreboff et al., 2022; Qin et al., 2024).
These outcomes are significant when compared to lifestyle interventions alone, which typically result in more modest weight loss (Wadden et al., 2023).
Many people describe a reduction in what is often referred to as “food noise”, and in practice this can result in individuals eating significantly less, sometimes only one meal per day with minimal snacking. This substantial reduction can lead to rapid weight loss and is largely driven by the appetite-regulating effects of these medications.
GLP-1 receptor agonists enhance satiety, delay gastric emptying, and reduce energy intake via central and peripheral mechanisms involving the gut–brain axis (Nauck & Müller, 2023). Reductions in energy intake of up to 39% have been reported (Christensen et al., 2024), but in practice many people report anecdotally that they are eating less than half in volume than they would do normally.
While this reduction in intake supports weight loss, in many cases it also dramatically increases the risk of nutritional deficiencies if not appropriately managed. Evidence suggests that individuals using GLP-1 medication may not meet recommended, let alone optimal, intakes for many essential nutrients, including iron, calcium, magnesium, potassium and vitamins A, C, D and E (Christensen et al., 2024). The potential consequences of this can include symptoms such as fatigue, muscle weakness, reduced immune function and may also in turn influence weight loss outcomes.
This highlights the importance of nutritional input alongside pharmacological intervention, rather than viewing medication as a standalone solution.
Muscle loss and metabolic impact
One of the biggest concerns is that weight loss associated with GLP-1 medication may include a proportion of lean body mass. Studies suggest that between 20-50% of weight lost may be from muscle (Neeland et al., 2024). Preservation of lean mass is extremely important for metabolic health, physical function and long-term weight maintenance.
Adequate protein intake and resistance-based physical activity are therefore key considerations. Without these, there may be an increased risk of reduced metabolic rate and greater likelihood of weight regain. There may also be longer-term implications for musculoskeletal health, including bone density.
Adequate protein intake is essential not only for maintaining muscle mass but also for the production of neurotransmitters that regulate mood, appetite and cognitive function. Amino acids derived from dietary protein are required for the synthesis of key neurotransmitters such as serotonin and dopamine, which play a role in appetite regulation and reward pathways (Fernstrom, 2013).
Where protein intake is significantly reduced, as may occur with appetite suppression, this may have implications for mood regulation, energy levels and overall neurological function.
While many individuals report this reduction in “food noise” when using GLP-1 medication, it is important to consider whether this reflects improved regulation or pharmacological suppression of appetite signals. Without adequate nutritional support and knowledge, there is a risk that the underlying drivers of eating behaviour are not fully addressed.
Gastrointestinal side effects are commonly reported with GLP-1 medications including nausea, constipation, diarrhoea and bloating. These effects may influence the amount and type of foods eaten. In addition, ongoing digestive symptoms may further impact nutrient intake and absorption, potentially increasing the risk of nutritional deficiencies.
More serious, although less common, adverse effects include pancreatitis and gallbladder disease. The mechanisms underlying these risks are not fully understood; however, GLP-1 medications influence pancreatic function and may alter enzyme activity, which has led to concerns regarding pancreatic inflammation. In relation to gallbladder health, rapid weight loss, reduced dietary intake of fat, and potential effects on gallbladder motility may contribute to an increased risk of gallstone formation.
Rapid weight loss is also associated with reductions in bone mineral density, particularly where there is concurrent loss of lean body mass (Shapses & Sukumar, 2012). https://pubmed.ncbi.nlm.nih.gov/22809104/ Emerging evidence suggests that GLP-1 medication may contribute to this through significant weight and muscle loss, although a direct causal link to osteoporosis has not yet been established (Neeland et al., 2024). This highlights a potential risk to bone health, particularly in the absence of adequate nutrition and resistance-based exercise.
There is also a growing awareness of less discussed effects, such as rapid changes in facial appearance (“Ozempic face”), where you see hollowing around the cheeks, more visible lines and wrinkles and saggy skin. Some individuals report looking more drawn, pale or grey; in practice this may relate to low iron, B vitamins (especially B12, folate and B6), and essential fatty acids (e.g. omega-3).
Evidence is also growing that weight regain may occur following discontinuation of GLP-1 medication. Some studies suggest that a substantial proportion of weight lost may be regained within several years (Tzang et al., 2025). This raises important questions as to whether this is a sustainable public health strategy. If people cannot manage to keep off the weight, then are they being given the right dietary advice? These findings highlight the importance of addressing nutritional, behavioural and lifestyle factors alongside any pharmacological treatment. Without this, long-term weight management may be challenging. In practice, this may also impact psychological wellbeing, particularly where individuals feel dependent on ongoing treatment to maintain results.
From a nutritional perspective, key areas of focus include ensuring adequate intake of essential nutrients, supporting protein intake to preserve lean body mass, and addressing any gastrointestinal side effects that may impact food intake. It is particularly important that the food consumed is nutrient-dense to support overall health.
As naturopathic nutritional therapists, we also recognise that lifestyle factors such as physical activity, sleep and stress management play a fundamental role in supporting metabolic health and long-term weight maintenance. We may contribute to supporting individuals using GLP-1 medication by providing personalised dietary guidance and supplementation, monitoring nutritional status, and supporting behavioural change.
From a naturopathic nutritional therapist’s perspective, sustainable weight loss is not about suppressing appetite, it is about supporting the body to optimise health and addressing the root causes of weight gain. This includes:
These changes may not produce rapid results, but they create a foundation for long-term health and weight stability.
While GLP-1 medications may offer a useful tool in certain circumstances, particularly where weight is a barrier to medical treatment or mobility, they should not replace the need for comprehensive nutritional and lifestyle support.
Without this, there is a risk that the underlying drivers of weight gain remain unaddressed, making long-term success more difficult to achieve.
NNA’s Annual Conference: Naturopathic Strategies for the GLP-1 Era: Nutrition, Lifestyle and Beyond takes place on Saturday 25 April 2026 in Bishopsgate, London. Find out more about the event and book your place here.