What is GLP-1, and how does it help with weight management?ⁱ

As we break down food and convert it into energy, the gut releases a hormone called GLP-1 (glucagon-like peptide-1) that helps regulate metabolism. When blood sugar rises after a meal, GLP-1 signals that we are full and have sufficient energy, prompting the body to begin slowing key processes.

Digestion is then reduced to limit the intake of more food, the stomach empties more slowly to promote fullness, and the release of stomach acid, digestive enzymes, bile, and gut motility is decreased. GLP-1 also helps reduce appetite by lowering levels of hunger hormones such as ghrelin, making us feel less hungry and more satisfied.

Insulin is a natural hormone made by the pancreas. Its main job is to help sugar (glucose) from food get into your body’s cells, where it’s used for energy. GLP-1 enhances insulin release and action, allowing sugar in the bloodstream to be taken up by cells more efficiently, thereby supporting energy production and maintaining balanced blood sugar levels.

Together with the natural slowing of digestion and absorption of macronutrients such as carbohydrates, this further improves insulin sensitivity. ^{ii, iii}

What are GLP-1 medications?

GLP-1 is a powerful hormone that regulates appetite and metabolism, but it only stepped into the spotlight around 20 years ago with the arrival of drugs designed to mimic its effects in people with diabetes. People soon noticed that these medications also improved weight loss.

This observation sparked intense interest from the pharmaceutical industry and led to the development of GLP-1–based treatments specifically for weight management. Today, injections such as Ozempic, Wegovy, and Mounjaro have surged in popularity, with millions of people paying privately to access them, drawn by the promise of rapid and significant weight loss.^iv

However, it is important to acknowledge that there is a difference between the GLP-1 our bodies naturally produce daily and high-dose synthetic injections given weekly. This raises important questions about whether higher doses may carry risks.

GLP-1 medications: are there any side effects?

Poor nutritional intake

GLP-1 medications lead to a significant reduction in overall food intake. Eating less means consuming fewer macronutrients, including protein, which can negatively affect muscle mass and energy levels.

Since healthy muscle mass is important for maintaining metabolism and supporting body composition, this raises important questions about how helpful this approach is for long-term weight management. Lower food intake, especially if food quality is poor, can also reduce micronutrient intake, increasing the risk of deficiencies in essential vitamins and minerals.

Digestive issues

The way GLP-1 medications act on the digestive system can reduce the body’s ability to break down food and absorb its nutritional value due to lower production of stomach acid, digestive enzymes, and bile.

This may be why people taking these medications often report symptoms such as bloating, constipation, abdominal pain, acid reflux, and nutrient deficiencies, as well as longer-term health issues such as osteoporosis and sarcopenia. Changes in bile flow have also been suggested to contribute to cholesterol imbalances, as well as pancreatic and liver issues.^{vi, vii}

Reduced intake of fibre-rich foods, which are often quite filling and therefore avoided, can lead to reduced diversity of the gut microbiome. Gut health is essential for overall health, playing a central role in digestion, immunity, hormone balance, inflammation control, and communication with the brain.

Mental health

While some research suggests that GLP-1 medications may positively influence neurotransmitters such as serotonin and dopamine, and weight loss may improve self-esteem for some, there are also reports of low mood and depression.^viii>

We must also consider how these drugs may limit social connections, shared meals, and the psychological impact of dramatic weight loss. Poor intake of micronutrients such as B vitamins and vitamin D can negatively affect neurotransmitter production involved in mood regulation.

Medication cessation

Research suggests that stopping GLP-1 medications can lead to rebound weight gain, while ongoing use may require higher doses over time as the body adapts. The implications of long-term use, including unknown potential side effects, therefore need careful consideration.^ix

How can you increase GLP-1 naturally with diet and lifestyle?

Protein

Good quality protein plays a key role in regulating blood sugar levels and is one of the strongest natural stimulators of GLP-1 release. By slowing digestion and promoting stable post-meal glucose responses, protein supports appetite regulation and satiety.

Adequate protein intake is also essential for maintaining muscle mass and metabolic health. Including protein at each meal can help support sustained weight loss and overall metabolic function.

Fibre

Fibre, found in fruits, vegetables, and wholegrains, is essential for healthy digestion. When fibre is broken down in the gut, it produces short-chain fatty acids (SCFAs), which stimulate natural GLP-1 release and support satiety.

A fibre-rich diet, including fermented foods where appropriate, and considering probiotic support can help maintain a healthy gut microbiome and support weight management.^x

Healthy fats

Healthy fats such as extra virgin olive oil, avocados, nuts, and seeds help slow digestion, promote fullness, and stimulate GLP-1 and other satiety hormones.

They also support bile acid signalling and gut–brain communication, contributing to better appetite control and stable blood sugar levels.

Exercise

Physical activity, particularly resistance training, supports muscle mass, body composition, endorphin release, and increases GLP-1 sensitivity and release.

Sleep

Quality sleep plays a crucial role in appetite regulation. When sleep is disrupted, GLP-1 signalling can be reduced, increasing hunger and cravings the following day.

Are there natural alternatives to GLP-1 jabs?

Saccharomyces cerevisiae peptides

Saccharomyces cerevisiae contains naturally occurring peptides (DNF-10 peptides) that may support GLP-1 by slowing the enzymes responsible for breaking it down.

By helping GLP-1 remain active for longer after meals, these peptides may support appetite control, insulin release, balanced blood sugar levels, and slower gastric emptying. This approach protects naturally released GLP-1 rather than overstimulating production.

Research suggests this may lead to reduced calorie intake and meaningful fat loss, including reductions in abdominal fat and waist circumference.^xi,xii,xiii

Polyphenols

Polyphenols are plant compounds found in fruits, vegetables, tea, coffee, and spices such as turmeric. Studies suggest they can directly stimulate GLP-1 secretion after meals.

Some polyphenols also enhance GLP-1 indirectly by supporting gut microbiota and SCFA production. Cinnamon, quercetin, green tea, luteolin, grapeseed, and black seed have all been highlighted in research.^xvi

Omega-3

Omega-3 fatty acids help reduce inflammation, support gut health, improve blood sugar balance, and may stimulate GLP-1 release through gut fat-sensing receptors and bile acid signalling.

Conclusion

A healthy, whole-food diet rich in fibre, micronutrient-dense fruits and vegetables, adequate protein, and healthy fats forms the foundation for balanced blood sugar and appetite control.

When combined with stress management, good sleep, gentle movement after meals, and gut health support, these habits enhance the body’s natural satiety hormones and create a sustainable, long-term approach to weight management and overall well-being.

References

ⁱDrucker DJ. (2018) Mechanisms of Action and Therapeutic Application of Glucagon-like Peptide-1. Cell Metab. Apr 3;27(4):740-756.

ⁱⁱChai, W., et al. (2014). Glucagon-like peptide 1 recruits muscle microvasculature and improves insulin’s metabolic action in the presence of insulin resistance. Diabetes, 63(8), 2788–2799.

ⁱⁱⁱLiu Q. K. (2024). Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists. Frontiers in endocrinology, 15, 1431292.

^iv https://news.sky.com/story/ozempic-to-mounjaro-what-are-the-weight-loss-injections-and-what-were-they-designed-to-do-12823419#:~:text=An%20estimated%201.5%20million%20people,through%20specialist%20weight%20management%20services.

^vDirksen C, Madsbad S. Body composition during major incretin-based weight loss. The Lancet Diabetes & Endocrinology. 2025;13(8):638-640. doi:https://doi.org/10.1016/s2213-8587(25)00122-6 ‌

^viHe L, Wang J, Ping F, et al. (2022) Association of glucagon-like peptide-1 receptor agonist use with risk of gallbladder and biliary diseases: a systematic review and meta-analysis of randomized clinical trials. JAMA Intern Med 2022; 182(5):513–519.inflammasome/PFKFB3-driven glycolysis interaction and histone lactylation. Journal of translational medicine, 22(1), 954.

^viiPostlethwaite R, Amin AM, Alsawas R, Almandoz JP, Sawas T. Predictors of acute pancreatitis in patients treated with GLP-1 receptor agonists for weight management. Pancreatology. 2025;25(5):609-613. doi:https://doi.org/10.1016/j.pan.2025.06.018 ‌

^viiiKrupa A. J. (2025). Curbing the appetites and restoring the capacity for satisfaction: The impact of GLP-1 agonists on the reward circuitry. Neuroscience applied, 4, 105512.

^ix Wu H, et al. (2025) Trajectory of the body weight after drug discontinuation in the treatment of anti-obesity medications. BMC Med. 22;23(1):398.

^xEren-Yazicioglu CY, Yigit A, Dogruoz RE, Yapici-Eser H. Can GLP-1 Be a Target for Reward System Related Disorders? A Qualitative Synthesis and Systematic Review Analysis of Studies on Palatable Food, Drugs of Abuse, and Alcohol. Frontiers in Behavioral Neuroscience. 2021;14. doi:https://doi.org/10.3389/fnbeh.2020.614884 ‌

^xiKasina SVSK, Baradhi KM. Dipeptidyl Peptidase IV (DPP IV) Inhibitors. [Updated 2023 May 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.

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^xiiiJung EY, Cho MK, Hong YH, Kim JH, Park Y, Chang UJ, Suh HJ. Yeast hydrolysate can reduce body weight and abdominal fat accumulation in obese adults. Nutrition. 2014 Jan;30(1):25-32

 ^xivHaldar S, Chia SC, Henry CJ. Polyphenol-rich curry made with mixed spices and vegetables increases postprandial plasma GLP-1 concentration in a dose-dependent manner. European Journal of Clinical Nutrition. 2018;72(2):297-300. doi:https://doi.org/10.1038/s41430-017-0069-7

^xvHlebowicz J, Hlebowicz A, Lindstedt S, et al. Effects of 1 and 3 g cinnamon on gastric emptying, satiety, and postprandial blood glucose, insulin, glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and ghrelin concentrations in healthy subjects. The American Journal of Clinical Nutrition. 2009;89(3):815-821. doi:https://doi.org/10.3945/ajcn.2008.26807

^xviWang Y, Alkhalidy H, Liu D. The Emerging Role of Polyphenols in the Management of Type 2 Diabetes. Molecules. 2021;26(3):703. doi:https://doi.org/10.3390/molecules26030703