GLP-1 agonists are all the rage right now.  But, what is GLP-1 anyway?  Do our bodies make it naturally, and if so, is there a way to boost our body’s natural production of this peptide?

What is GLP-1?

GLP-1 stands for glucagon-like peptide-1.  Along with GIP (glucose-dependent insulinotropic polypeptide), these incretin peptides are released from the small intestines in response to consumption of nutrients (Nauck & Meier, 2018).  

The incretins GLP-1 and GIP promote a surge in insulin secretion after a meal.  GLP-1 also prevents the liver from releasing glucose stores into the blood, bringing blood sugar levels down to lower, better controlled levels.

GLP-1 has notable appetite suppressing effects, and displays activity with adipose cells, bone tissue, and with cardiovascular system receptors (Nauck & Meier, 2018).

Release of GLP-1 may be impaired in obese individuals (Nauck & Meier, 2018). 

The benefits of GLP-1 are becoming more clear as people take medications that stimulate the same receptors as our body’s GLP-1 peptide.   

GLP-1 Agonist Medications 

Stating that GLP-1 agonist medications have revolutionized weight loss medicine is an understatement.  It seems that clinics both online and across the country are cropping up constantly, ready to offer GLP-1 therapy to an eager market (Nauck & Meier, 2018).

The benefits of GLP-1 medications have been consistently noted in patients and research studies over the past several years and include:

• 5-10% body weight reduction in 1 year (note: much more than this is possible with additional interventions including lifestyle changes)
• Reduced cravings, can be dramatic in beginning 
• Reduced hunger sensations, can be dramatic in beginning   
• Slowed gastric emptying (feel fuller longer)
• Improved insulin sensitivity (brings down fat storage signaling)
• Reduced risk of death from heart attack
• Reduced risk of non-fatal heart attacks and cardiac events
• Reduced risk of non-fatal strokes
• 20% reduction in total cardiovascular events
• Reduced inflammation (as measured by C-reactive protein) (Ryan et al., 2024; Mahapatra, Karuppasamy, & Sahoo, 2022; Lincoff et al., 2023; Wilding et al., 2022; Sandsdal et al., 2023).

However, GLP-1 medications can cause side effects such as nausea, constipation or diarrhea, fatigue, among others, leading to premature discontinuation of these medications prior to clients achieving these benefits (Wilding et al., 2022).  

Further, while costs have become more competitive, GLP-1 medications are frequently not covered by insurers or have large co-pays, making their ongoing affordability a challenge.  

Compounding medications are much cheaper than brand name versions but care must be taken to ensure these medications are secured by reputable compounding pharmacies, such as U.S. based compounding pharmacies using U.S. manufactured ingredients.  More about compounding pharmacies and regulations can be found on the FDA webpage here.

What foods and nutrients stimulate GLP-1 release per research?

With all the great benefits from GLP-1 receptor stimulation, are there ways to stimulate or “boost” our own body’s production of GLP-1?  What foods promote the release of GLP-1?

According to a research review in the journal Nutrition & Metabolism (Bodnaruc et al., 2016), the foods listed below caused the release of GLP-1 in humans.

Carbohydrates:  slow digesting and fiber rich in particular!

Yes, carbohydrates are a promoter of GLP-1 peptide release.  This is not entirely a surprise given that research on satiety has found fruit to be the most filling food category when compared to a variety of common foods (such as meat, yogurt, whole grains, etc) (Holt et al., 1995).  

What is fascinating, however, is that as carbohydrate foods move further through the intestine, they continue to interact with the cells responsible for secreting GLP-1 leading to prolonged GLP-1 release and its effects (Bodnaruc et al., 2016). 

This means that slow digesting less-processed carbohydrates such as fruits, vegetables, beans, whole grains, and nuts may produce longer GLP-1 stimulation effects as they pass through the intestines versus more rapidly absorbed carbohydrates like refined flours and sugars.  

Further evidence of the benefits of whole food plants beneficially stimulating GLP-1 release comes from the effects of bacterial fermentation of fiber (only found in plants) in the colon. 

As gut bacteria ferment fiber from fruits, vegetables, whole grains, nuts, and beans in the colon, short-chain fatty-acids are produced as a byproduct (Bodnaruc et al., 2016).

Both fiber and its byproducts produced in the colon also stimulate GLP-1 release from cells in the colon (Bodnaruc et al., 2016).  Ingestion of fiber rich foods thus has been linked to weight loss, lower food consumption, and reductions of triglycerides in the liver (fat deposits in the liver).

These effects may occur over a time frame of 6 hours, producing a “second effect” of appetite reduction as fibrous plant-based foods reach the colon (Bodnaruc et al., 2016). 

Unsaturated fats superior to saturated fats: think flaxseeds, olive oil, nuts, and plants!

Research comparing the effects of saturated fat (the study used butter) versus unsaturated fat (the study comparison group used olive oil) found that the unsaturated fat in olive oil was significantly superior in raising GLP-1 versus the saturated fat in butter (Bodnaruc et al., 2016)

Another GLP-1 stimulating fat includes the plant-based omega-3 fatty acid α-linolenic acid (ALA).  ALA is  found in many plants but is particularly rich in flaxseed, chia seeds, walnuts, and hemp seeds (Bodnaruc et al., 2016).

Protein

A variety of amino acids found in both plant and animal proteins stimulate the production of GLP-1 (Bodnaruc et al., 2016).  Since meat protein sources contain saturated fat whereas plant protein sources contain unsaturated fats described above, combining the plant-protein sources with plant-based fat sources (such as protein and ALA found in beans, lentils, edamame, nuts) may pack a more potent punch for GLP-1 production.

And indeed, this is a study found in diabetics when comparing a meat-based meal versus a plant-based meal containing equal amounts of protein as outlined below! 

Diabetics & meat-based meals versus plant-based meals:  which work better to stimulate GLP-1 release? 

Two well designed studies have shown a clear link between plant-based meals and boosted GLP-1 levels when compared to meat-based meals.

A randomized-controlled crossover clinical trial had diabetic participants consume either a plant-based meal (tofu-based burger) or a meat-based meal (hamburger) first thing in the morning after fasting 10 -12 hours.  They also consumed a hot beverage with the meal–a caffe latte with the hamburger, or a green tea with the tofu-based burger (Kahleova et al., 2019).

The plant-based meal and meat-based meal were matched for calories and macronutrients (protein, carbohydrates, fat).  

They measured levels of incretins along with other hormones and enzymes (insulin, amylin, glucose, c-peptide) prior to the meal, then from 30 min to 180 minutes after the meal.

The plant-based protein meal boosted GLP-1 levels significantly higher than the animal based protein meal.  Further, the plant-based meal also boosted the satiety peptide amylin significantly higher, produced a significantly more healthy insulin response in these diabetic subjects, and promoted a lower GIP response (GIP spikes after meals are associated with fat storage signaling).

Study summary:  the plant-based burger led to higher levels of appetite suppression/ satisfaction, as well as lower hormonal fat-storage signaling compared to a calorie matched, protein/ carb/ fat matched hamburger.

Separate study, similar results

In a similar study, a cheeseburger meal rich in protein and fat was compared to a plant-based meal high in carbohydrates (containing couscous, oat flakes, along with spices such as onion, garlic, etc) in a randomized cross-over trial involving both diabetic and healthy overweight adults (Belinova et al., 2014).  

Once again, calories were kept equal, though carbohydrate/ protein/ fat content differed between the plant-based burger and the meat-based burger.  

In this case, diabetics experienced dramatic increases in GLP-1 following the plant-based burger versus when they consumed the meat-based burger (Belinova et al., 2014), while for non-diabetics the difference was minimal.  

This is important because GLP-1 release post-meals is known to be impaired in diabetics, yet, for diabetics consuming the plant-based meal, GLP-1 release was more than double the levels stimulated by a meat-based meal (Belinova et al., 2014).  

Other interesting findings:

• The meat based cheeseburger caused higher levels of insulin to be secreted for a longer period of time following the meal consumption compared to the plant-based burger, even though the plant-based burger had more carbohydrates.
• In diabetics, the plant-based meal stimulated the highest levels of post-meal satiety hormones (PP, PYY, GIP,GLP-1) whereas in non-diabetic/ healthy individuals the meat based meal produced higher levels of these hormones, though this difference between meat & plant-based meals was relatively small in healthy individuals.
• In healthy individuals, the fat from the meat based meal was better at suppressing after meal hormone levels of ghrelin which is a hunger-stimulating hormone.  The researchers note that fat is the most potent stimulant for peptides PP and PYY.  In diabetics, responses to dietary fat in terms of appetite suppression appear impaired.

Study summary: once again, in diabetics, GLP-1 release following a plant-based meal high in carbohydrates was significantly higher than when diabetics ate a meat based meal.  The difference in satiety hormone response to a plant-based meal or meat based meal was much smaller in healthy individuals, with the meat based meal producing a similar GLP-1 response to the plant-based meal during the 2 hours of measurements.  

Note: measurements over a longer period of time were not taken, so the “second effect” of GLP-1 increase from plant-based food fiber reaching the colon was not evaluated in this study.

With plant based food components such as carbohydrates, fiber, unsaturated fats and ALA, plus protein all supporting increases in GLP-1 levels, a person may expect to find those consuming plant-based diets to be thinner than those consuming diets rich in animal foods.

And, this is exactly what researchers have found!

Plant-based meals:  as they increase, body weight decreases

Research on persons eating plant-based diets are more lean on a sliding scale depending on how frequently they consume plant-based meals versus animal based meals.

In a study of more than 20,000 men and 38,000 women (Pillas et al., 2014):

• Regular meat consumers had the highest BMI at 28 on average
• Those that ate meat occasionally were lighter than regular meat eaters
• Those that eliminated meat but ate fish were lighter than occasional meat eaters
• Those that ate no meat or fish but ate eggs and dairy were lighter than those who ate fish but no meat
• Vegans had the lowest BMI at 23 on average

A separate study published in the British Medical Journal with nearly 11,000 subjects found a similar sliding scale for body weight and plant-based meals (Wozniak et al., 2020):

• Those eating the most meat had the highest BMI
• Those eating a diet based on both plant based meals and animal based meals had a slightly lower BMI (-0.66 points compared to regular meat eaters)
• Those eating a diet that eliminated all meat except fish had an even lower BMI (-1.7 points)
• Vegetarians (who still ate eggs and dairy) had the lowest BMIs (-2.22 points).  In this study vegans were not separated from vegetarians.

How can Lancaster Wellness help me?

At Lancaster Wellness, we use a combination of GLP-1 medications, oral medications, and lifestyle coaching/ lifestyle shifting to help clients achieve weight loss results they often felt were impossible.

We closely monitor our clients and help them through any adjustments with the medication, including tailoring doses as necessary to meet individual needs depending on tolerance and symptoms.

Additionally, many clients who have fully embraced the research-backed lifestyle changes taught during the weight loss program have kept the weight off for years following their journey with Lancaster Wellness.

Our team has a deep passion for lifestyle medicine and includes certified health coaches, certified personal trainers, registered nurses, and is directly supervised by Dr. Ruziev.  

Summary

GLP-1 peptide and medication versions of GLP-1 (which bind to GLP-1 receptors in the body) are powerful tools for supporting appetite management and for promoting improvements in cardiovascular health, blood sugar control, and weight. 

Plant-based shifts may promote increased production of natural GLP-1 peptide in addition to promoting other favorable hormone and peptide secretions following a meal.

Plant-based diets appear to have a dose-effect, with increasing percentages of food coming from plants linked to progressively lower body weights. 

Lancaster Wellness can help you achieve your goals with our proven results, 360-degree, weight loss program.  Call us today to schedule your free consultation!!! 

-Written by Donovan Carper MSN RN CPT CHC

References

Belinova, L., Kahleova, H., Malinska, H., Topolcan, O., Vrzalova, J., Oliyarnyk, O., Kazdova, L., Hill, M., & Pelikanova, T. (2014). Differential acute postprandial effects of processed meat and isocaloric vegan meals on the gastrointestinal hormone response in subjects suffering from type 2 diabetes and healthy controls: a randomized crossover study. PloS one, 9(9), e107561. https://doi.org/10.1371/journal.pone.0107561 

Bodnaruc, A. M., Prud’homme, D., Blanchet, R., & Giroux, I. (2016). Nutritional modulation of endogenous glucagon-like peptide-1 secretion: a review. Nutrition & metabolism, 13, 92. https://doi.org/10.1186/s12986-016-0153-3 

Holt, S. H., Miller, J. C., Petocz, P., & Farmakalidis, E. (1995). A satiety index of common foods. European journal of clinical nutrition, 49(9), 675–690. Retrieved from https://www.researchgate.net/profile/Peter-Petocz/publication/15701207_A_Satiety_Index_of_common_foods/links/00b495189da413c16d000000/A-Satiety-Index-of-common-foods.pdf 

Kahleova, H., Tura, A., Klementova, M., Thieme, L., Haluzik, M., Pavlovicova, R., Hill, M., & Pelikanova, T. (2019). A Plant-Based Meal Stimulates Incretin and Insulin Secretion More Than an Energy- and Macronutrient-Matched Standard Meal in Type 2 Diabetes: A Randomized Crossover Study. Nutrients, 11(3), 486. https://doi.org/10.3390/nu11030486

Lincoff, A. M., Brown-Frandsen, K., Colhoun, H. M., Deanfield, J., Emerson, S. S., Esbjerg, S., Hardt-Lindberg, S., Hovingh, G. K., Kahn, S. E., Kushner, R. F., Lingvay, I., Oral, T. K., Michelsen, M. M., Plutzky, J., Tornøe, C. W., Ryan, D. H., & SELECT Trial Investigators (2023). Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. The New England journal of medicine, 389(24), 2221–2232. https://doi.org/10.1056/NEJMoa2307563

Mahapatra, M. K., Karuppasamy, M., & Sahoo, B. M. (2022). Semaglutide, a glucagon like peptide-1 receptor agonist with cardiovascular benefits for management of type 2 diabetes. Reviews in endocrine & metabolic disorders, 23(3), 521–539. https://doi.org/10.1007/s11154-021-09699-1 

Nauck, M. A., & Meier, J. J. (2018). Incretin hormones: Their role in health and disease. Diabetes, obesity & metabolism, 20 Suppl 1, 5–21. https://doi.org/10.1111/dom.13129

Pilis, W., Stec, K., Zych, M., & Pilis, A. (2014). Health benefits and risk associated with adopting a vegetarian diet. Roczniki Panstwowego Zakladu Hygieni, 65(1), 9-14. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/24964573

Ryan, D. H., Lingvay, I., Deanfield, J., Kahn, S. E., Barros, E., Burguera, B., Colhoun, H. M., Cercato, C., Dicker, D., Horn, D. B., Hovingh, G. K., Jeppesen, O. K., Kokkinos, A., Lincoff, A. M., Meyhöfer, S. M., Oral, T. K., Plutzky, J., van Beek, A. P., Wilding, J. P. H., & Kushner, R. F. (2024). Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial. Nature medicine, 10.1038/s41591-024-02996-7. Advance online publication. https://doi.org/10.1038/s41591-024-02996-7 

Sandsdal, R. M., Juhl, C. R., Jensen, S. B. K., Lundgren, J. R., Janus, C., Blond, M. B., Rosenkilde, M., Bogh, A. F., Gliemann, L., Jensen, J. B., Antoniades, C., Stallknecht, B. M., Holst, J. J., Madsbad, S., & Torekov, S. S. (2023). Combination of exercise and GLP-1 receptor agonist treatment reduces severity of metabolic syndrome, abdominal obesity, and inflammation: a randomized controlled trial. Cardiovascular diabetology, 22(1), 41. https://doi.org/10.1186/s12933-023-01765-z 

Wilding, J. P. H., Batterham, R. L., Davies, M., Van Gaal, L. F., Kandler, K., Konakli, K., Lingvay, I., McGowan, B. M., Oral, T. K., Rosenstock, J., Wadden, T. A., Wharton, S., Yokote, K., Kushner, R. F., & STEP 1 Study Group (2022). Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes, obesity & metabolism, 24(8), 1553–1564. https://doi.org/10.1111/dom.14725 

Wozniak, H., Larpin, C., de Mestral, C., Guessous, I., Reny, J. L., & Stringhini, S. (2020). Vegetarian, pescatarian and flexitarian diets: sociodemographic determinants and association with cardiovascular risk factors in a Swiss urban population. The British journal of nutrition, 124(8), 844–852. https://doi.org/10.1017/S0007114520001762