Taking medications such as Wegovy (Semaglutide) or Mounjaro (Tirzepatide) can change how you experience food. Portions may naturally shrink, fullness may arrive quickly, and the urge to snack or graze may diminish. While this helps control appetite, it can sometimes lead to habits that reduce nutrient intake, such as skipping meals or missing protein.
Structured meals ensure that the appetite-suppressing effects of these medications support healthy weight loss rather than nutrient gaps. Three balanced meals, spaced throughout the day, remain one of the most reliable ways to maintain energy, meet nutrient needs, and preserve muscle while on these medications.
How These Medications Affect Appetite and Intake
Clinical trials consistently show that these medications reduce overall food intake by suppressing appetite and cravings:
- Wegovy (Semaglutide): Adults taking weekly injections ate significantly less across all meals and snacks compared with placebo. Semaglutide also reduced hunger, cravings, and preference for high-fat foods (Wilding et al., 2021).
- Mounjaro (Tirzepatide): In a 6-week trial, participants consumed around 525 kcal less at a controlled lunch than those on placebo, alongside lower appetite and reduced drive to eat (Martin et al., 2025).
These findings show that total food intake decreases reliably when appetite is suppressed. As a result, relying solely on hunger to guide meals may not provide enough nutrition, particularly protein.
Why Protein Becomes Even More Important
When appetite is reduced, the calories you do eat become even more valuable. Protein is a priority because it:
- Preserves muscle mass: Adequate protein protects lean tissue when total intake decreases.
- Supports metabolism: Digesting protein burns more energy than carbohydrates or fats.
- Promotes fullness: Protein stabilises appetite and reduces the urge to snack unnecessarily.
- Optimises each meal: With smaller meal sizes, including protein ensures nutrient needs are met.
Practical protein sources: eggs, fish, chicken, turkey, low-fat dairy, Greek/Skyr yoghurt, unsweetened soya milk or yoghurt, beans, lentils, tofu, tempeh, cottage cheese, nuts, and seeds.
Protein needs may increase during GLP-1 therapy, yet many patients do not meet these requirements (Johnson et al., 2025). Including protein at every meal helps maintain muscle, supports safe weight loss, and ensures overall nutrition.
For more guidance on meal planning while on treatment, see our articles on what to eat on Wegovy and what to eat on Mounjaro.
Meal Timing and Your Body Clock
Your body runs on a natural circadian rhythm, a 24-hour biological clock that influences digestion, hormone release, glucose metabolism, and energy regulation. Research shows that when you eat can affect how your body processes nutrients.
- Earlier dinners improve metabolic responses: A randomised crossover trial found that eating an early dinner (18:00) compared with a later dinner (21:00) improved 24-hour blood glucose levels and lipid metabolism, demonstrating that timing meals earlier can potentially support better nutrient processing (Yoshida et al., 2021).
For shift workers: The same principles apply, but meals should be spaced evenly throughout waking hours rather than tied to traditional breakfast, lunch, and dinner times. Structured eating remains important even if your schedule is atypical; avoiding random snacking helps regulate hunger.
Snacking vs. Structured Meals
Because appetite may be reduced, some people may be tempted to graze or snack throughout the day or eating only when hunger strikes. While snacking is perfectly fine, it should not replace balanced meals, which provide essential nutrients and protein.
- Snacks are best used to satisfy hunger between meals and ideally should be nutrient and protein-rich, for example, fruit with yoghurt, a boiled egg, a small handful of nuts, or a protein smoothie or shake. For ideas on creating balanced snacks, see our guide on how to create a balanced snack.
- Skipping meals or relying only on snacks can make it difficult to meet protein and nutrient needs, and may compromise muscle, metabolism, and overall health.
- Grazing all day increases the risk of under-eating or low-quality nutrition. Structured meals or planned eating occasions are more reliable for sustaining energy and nutrition.
By focusing on three balanced meals and using snacks strategically to address hunger, you can help preserve muscle, maintain energy, and enjoy a more stable appetite throughout the day.
Intermittent Fasting or Restricted Eating Windows
Some people using GLP1 therapy may choose to combine it with intermittent fasting (IF) or a restricted eating window (for example, eating within eight hours a day). This can work, but it requires careful planning:
- Even in a shorter window, your body still needs enough calories, protein, and nutrients.
- Meals should be balanced and include a source of protein. Skipping meals and snacking can make it difficult to meet nutritional needs.
- Align the eating window with daylight when possible (for example, mid-morning to early evening) to support digestion, hormonal balance, and metabolic health.
- Avoid late-night eating. Heavy evening meals or snacks can interfere with sleep, hormone rhythms, and digestion.
Key takeaways to planning your meal times
- Eat three balanced meals a day (or structured eating occasions), spaced to suit your schedule and natural rhythm.
- Prioritise protein at every meal to preserve muscle and support metabolism.
- Snacks are fine if you feel hungry between meals, but they should not replace main meals.
- Plan carefully if using restricted eating windows or intermittent fasting, meals should be nutrient- and protein-rich.
- Avoid relying solely on grazing or random snacks; structured mealtimes provide more reliable nutrition.
By combining weight loss medication with thoughtful meal planning, nutrient-dense foods, and structured timing, you support weight loss, long-term health, preserve muscle, and maintain energy, even when appetite is reduced.
References
Johnson, B., Milstead, M., Thomas, O., McGlasson, T., Green, L., Kreider, R., & Jones, R. (2025). Investigating nutrient intake during use of glucagon-like peptide-1 receptor agonist: a cross-sectional study. Frontiers in nutrition, 12, 1566498. https://doi.org/10.3389/fnut.2025.1566498
Martin, C. K., Carmichael, O. T., Carnell, S., Considine, R. V., Kareken, D. A., Dydak, U., Mattes, R. D., Scott, D., Shcherbinin, S., Nishiyama, H., Knights, A., Urva, S., Biernat, L., Pratt, E., Haupt, A., Mintun, M., Otero Svaldi, D., Milicevic, Z., & Coskun, T. (2025). Tirzepatide on ingestive behavior in adults with overweight or obesity: a randomized 6-week phase 1 trial. Nature medicine, 31(9), 3141–3150. https://doi.org/10.1038/s41591-025-03774-9
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., & STEP 1 Study Group (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. The New England journal of medicine, 384(11), 989–1002. https://doi.org/10.1056/NEJMoa2032183
Yoshida, Y., Hatori, M., & Nakajima, S. (2021). Early vs late dinner timing on 24hour glucose and lipid metabolism: A randomised crossover study. Clinical Nutrition, 40, 5697–5705. https://pubmed.ncbi.nlm.nih.gov/34371933
