Foods to Avoid When Taking Weight Loss Medications: Focusing on GLP-1 analogues

-Dr Werd Al-Najim, Liz Birdie and Ong Shi Yun

Weight loss is generally seen as a tough feat, especially if done rapidly and unsustainably. Even in decades long past, there has been a timeless obsession for a magic pill that could promote weight loss – targeting various aspects of energy intake and metabolism, from those that target the energy generating part of the cell (e.g. 2,4-DNP) to the appetite-suppressing drugs known as anorectics (e.g. amphetamines) in the mid-1900s, though many have been withdrawn from the market as a result of serious side effects (1-3).

More recently, there have been other safer and more effective anti-obesity medications (AOMs), such as the pancreatic lipase inhibitor orlistat (Xenical; Alli), the appetite-suppressant naltrexone/bupropion combination (Mysimba; Contrave), and the highly promising GLP-1 mimetics such as semaglutide (Wegovy; Ozempic) – which were discussed in greater detail in the article, “Insights on Anti-Obesity Medications: The Future is Now!”

Food-Drug Interactions

As with all pharmacological drugs, there is always a risk of unwanted interactions with specific foods (food-drug interactions). This article cannot cover all potential food and drug interactions with all weight loss medications, but it aims to inform you of important considerations to keep you safe along your weight-loss, health-gain journey, focusing on the GLP-1 analogues, such as Wegovy (Ozempic) and Saxenda. 

One way that foods can interact is by producing effects that are similar or opposite to those produced by the drug you are taking. Thus, it is important to avoid foods that amplify the side effects of your weight loss medication (and to take foods that may help alleviate those side effects). 

For example, due to its mechanism of action, Wegovy can lower blood sugar, and so it is important to take extra precautions when concurrently taking certain medications and herbal supplements, which can cause low blood sugar – with examples such as insulin and anti-diabetic drugs like sulfonylureas, prickly pear, and fenugreek (4, 5).

Another potentially serious side effect of Wegovy is pancreatitis, which can also be caused by excessive alcohol consumption (5, 6). Given the effects of alcohol on blood sugar levels, its risk of pancreatitis, and its interactions with the body’s system of drug metabolism and clearance, doctors may suggest avoiding drinking large volumes of alcohol while taking anti-obesity medications.

Additionally, given that one of the ways GLP-1 agonists work in controlling blood sugar is by slowing gastric emptying, Wegovy and Saxenda can cause certain abdominal side effects, most commonly nausea, vomiting, diarrhoea, and constipation (7). Avoiding greasy, sugary, and fried foods and opting for plainer and low-fat foods may help to reduce nausea – as will taking liquids frequently and going outdoors rather than lying down after food (6). Ginger and peppermint tea may also help with nausea, and rather than having a large meal, eating at a slower pace and smaller portions more frequently may work better (8).

Furthermore, the side effects of constipation and/or diarrhoea can also be managed by some simple changes (9). Drinking plenty of fluids can help improve symptoms of constipation, and can foods high in fibre, such as whole grains, fruits like bananas and prunes, and vegetables. Over-the-counter laxatives or stool softeners may be helpful if the lifestyle changes are not adequate in relieving constipation. Even with diarrhoea, it is still important to remain hydrated and eat high-fibre foods, and avoiding caffeine and dairy products may also help with diarrhoea, and over-the-counter medications may also help alleviate symptoms of diarrhoea.

Finally, given the aim of anti-obesity medications to promote weight loss, it would be sensible to avoid foods that oppose that aim and work against the anti-obesity medications you are taking. This would mean enhancing the effects of those medications with a healthy lifestyle and diet – one filled with physical activity, whole foods, and various fruits and vegetables in moderation, while reducing or avoiding foods that are highly processed and high in sugar, salt, and saturated fats.

Conclusion

Before taking any supplements or medications or embarking on major changes in your diet, speaking with your doctor or pharmacist can help to keep you safe in your lifelong journey in optimising your health and well-being. By coupling anti-obesity medications with a healthy lifestyle and diet – and also with evidence-based medical advice, such as from your local healthcare professionals and Beyond BMI, as well as plenty of support, such as through Beyond BMI’s health coaches and your friends and family – weight loss will no longer be unattainable, and maintaining a healthy lifestyle will become a sustainable and lifelong habit.

References

1. Dolgin E. A history of drugs on the weight list. Nature Medicine. 2012;18(6):843-.

2. Rodgers RJ, Tschöp MH, Wilding JP. Anti-obesity drugs: past, present and future. Dis Model Mech. 2012;5(5):621-6.

3. Müller TD, Blüher M, Tschöp MH, DiMarchi RD. Anti-obesity drug discovery: advances and challenges. Nat Rev Drug Discov. 2022;21(3):201-23.

4. Drugs.com. 4 Key Ozempic Side Effects to Watch Out For  [updated April 12, 2023. Available from: https://www.drugs.com/medical-answers/4-key-ozempic-side-effects-watch-3573389/.

5. Williamson JM. Ozempic Interactions: Alcohol, Medications, and Others 2022 [Available from: https://www.healthline.com/health/drugs/ozempic-interactions.

6. The Found Team. Ozempic foods to avoid: Are there any foods to stay away from? 2023 [Available from: https://joinfound.com/blogs/posts/ozempic-foods-to-avoid.

7. Wharton S, Calanna S, Davies M, Dicker D, Goldman B, Lingvay I, et al. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity, and the relationship between gastrointestinal adverse events and weight loss. Diabetes Obes Metab. 2022;24(1):94-105.

8. Marshall H. All About Saxenda: Healthline Media; 2023 [Available from: https://www.healthline.com/health/drugs/saxenda.

9. Richa DC. 10 Wegovy side effects and how to manage them: Ro;  [updated 26 July 2023. Available from: https://ro.co/weight-loss/wegovy-side-effects/.