Expert Reveals Top 7 Mounjaro Mistakes Sabotaging Weight Loss Goals
As 2026 progresses, interest in GLP-1 weight-loss medications such as Mounjaro continues to surge, with many individuals either beginning treatment or seriously considering it. However, a prominent expert in the field has issued a crucial warning, highlighting that users frequently fall into predictable traps that can undermine their progress.
Alistair Murray, chief operating officer and weight-loss specialist at British digital health company Phlo, regularly advises patients starting GLP-1 treatments. The former chief pharmacist observes recurring misunderstandings and moments of anxiety among patients, who often express regret about not being aware of these issues earlier. Mr Murray has pinpointed seven common errors and provides practical guidance on how to avoid them.
Mistake 1: Eating Out of Habit Rather Than Hunger
"One of the most frequent issues I encounter is patients stating, 'I usually have breakfast at this time,' and then consuming their regular meal despite not feeling hungry," explains Mr Murray. "They are simply following ingrained habits."
He emphasises that while GLP-1 medications reduce appetite, they cannot magically alter embedded behaviours. The moment when hunger diminishes presents a valuable opportunity to pause and question whether eating is driven by bodily need or routine. For many, this is the first time they have experienced such reflection.
Patients are encouraged to critically evaluate their meals. If someone previously consumed a carb-heavy breakfast, this inflection point allows them to realise they might be satisfied with a smaller, protein-dense alternative instead. The medication creates space for different choices, but conscious effort is required to embrace it.
Mistake 2: Rushing the Process Due to Deadlines
"A common scenario involves people signing up for treatment three or four weeks before a wedding or major event, expecting dramatic results, which is simply unrealistic," says Mr Murray.
He notes that the body needs time to adapt to GLP-1s. Gastrointestinal issues often arise initially, which is undesirable during important occasions. Appetite changes gradually, and individuals require time to understand how eating and daily life function on the medication, making it a highly personal process.
When patients feel progress is too slow, it often stems from setting overly ambitious timelines. Many cite online stories or social media results rather than focusing on what suits their body best. Slow, steady weight loss indicates the treatment is working correctly. Rushing doses or chasing rapid results can backfire, increasing side effects and leading to abandonment of a potentially effective regimen.
Mistake 3: Assuming Early Side Effects Are Permanent
"The most significant misunderstanding is believing that how you feel in the first week reflects the entire journey with weight-loss drugs," Mr Murray observes.
While side effects like diarrhoea, nausea, vomiting, or constipation can be challenging barriers, they are typically not permanent. In reality, these symptoms are most noticeable at the outset and often diminish as the body adjusts to the GLP-1. Minor dietary adjustments, improved hydration, and routine changes can make a substantial difference.
Planning and prioritising maintenance from day one are crucial. Opting for nutrient-dense, light meals sets a positive foundation. Higher drop-off rates between the first and second treatments suggest many who discontinue early might have succeeded with additional reassurance and professional support during the initial weeks.
Mistake 4: Neglecting Protein Intake
"A major missed opportunity is eating less overall without altering dietary composition, with protein often being the first casualty," Mr Murray states.
This can lead to fatigue, reduced meal satisfaction, and difficulty preserving muscle during weight loss. "Protein is your ally during weight loss because it promotes fullness and supports lean mass," he advises. A simple guideline is to make protein the centrepiece of each meal, then incorporate colour, fibre, and healthy fats around it.
Even small changes, such as swapping a carb-heavy breakfast for a protein-first option, can simplify the entire day. Including protein sources like eggs, yoghurt, chicken, fish, tofu, or beans at every meal or snack is recommended.
Mistake 5: Skimping on Fibre and Water
"People are often surprised that appetite suppression can inadvertently reduce fibre and fluid intake, simply because they are eating less and forgetting to drink," says Mr Murray.
Fibre and hydration are critical for feeling well during a weight-loss journey, especially if constipation arises. Fibre requires water to function effectively; if either is deficient, digestion can slow, causing discomfort that may prompt treatment discontinuation.
Establishing small habits, like keeping a water bottle nearby and consuming fibre-rich foods daily, can transform the experience. Gradually increasing fibre intake with vegetables, berries, oats, beans, lentils, whole grains, and chia seeds, paired with consistent water consumption, is beneficial. However, individuals with conditions like IBS or inflammatory bowel disease should consult a GP, dietitian, or specialist before dietary changes, as high-fibre foods may trigger symptoms in sensitive cases.
Mistake 6: Under-Eating During the Day and Compensating at Night
"A frequent pattern involves barely eating all day due to lack of hunger, followed by evenings becoming a danger zone for cravings, snacking, or overeating," Mr Murray explains.
This is not a willpower issue but the body attempting to catch up. Even with low appetite, regular nourishment is essential. Small, protein-forward meals earlier in the day can prevent late-night rebounds. While forcing eating is unnecessary, maintaining a steady routine helps avoid swings from 'nothing' to 'everything.'
This approach is key to forming lasting behaviours. A light but structured strategy, focusing on protein and fibre earlier, promotes calmer evenings.
Mistake 7: Focusing Solely on Weight Loss Metrics
"The scale can be useful but also misleading," warns Mr Murray. "If success is measured only by weekly numbers, you may overlook factors that predict long-term results: consistent habits, sleep quality, strength training, and daily coping mechanisms."
Weight loss accompanied by exhaustion, muscle loss, poor sleep, or constant restriction is rarely sustainable. Tracking supportive elements like energy levels, appetite stability, protein intake, hydration, fibre consumption, and strength is encouraged.
The most effective changes are those that can be maintained. Incorporating two to three strength sessions weekly and prioritising sleep help preserve muscle and regulate appetite, fostering lasting success.
