Like the plot of a 2000s teen movie, GLP-1 medications are like the main character who starts at a new school and becomes popular overnight. It may seem like the meds popped up out of nowhere, but the reality is they just…transferred. GLP-1 medications have been treating type 2 diabetes since 2005 - but that certainly hasn’t stopped the internet rumour mill. To get the facts about these diabetes-turned-obesity meds, we asked experts to share how GLP-1s lead to weight loss, what side effects to keep an eye on, and how to know if your weight-loss journey could benefit from adding medication.
What is a GLP-1 agonist?
GLP-1 (which stands for glucagon-like peptide) is a gut hormone released by specialised cells in your intestinal tract after you eat. “When you consume carbohydrates, GLP-1 boosts the amount of insulin the body makes in order to bring your blood sugar back to normal,” says Dr. Robert Kushner, M.D., professor of medicine and medical education at Northwestern University Feinberg School of Medicine in Chicago. It does this in two ways: by triggering extra insulin, a hormone that helps lower blood sugar levels, and by inhibiting glucagon, a hormone that raises blood sugar levels.
While GLP-1 naturally occurs in the body, it only lasts about two to three minutes upon release. But the drug form of GLP-1, known as GLP-1 agonists, can last up to 14 hours in your body. And that means the effects last a lot longer too.
So how do GLP-1 agonists work for weight loss?
“GLP-1 agonists activate the receptors in the body that respond to GLP-1,” says Kushner. In other words, they act like the body’s GLP-1. By activating receptors in the pancreas, they’re able to regulate insulin and control blood sugar. But they also activate receptors in the brain to curb appetite and in the gut to slow stomach emptying.
That’s why, notes Kushner, “when a person uses a GLP-1 agonist, they may feel less hungry, have less cravings and thoughts of food, and feel more full after a meal and between meals.” They may also raise your resting metabolism.
Altogether, this leads to weight loss - an average of 15% to 21% body weight, per studies on two popular GLP-1s published in the The New England Journal of Medicine.
What are the side effects of GLP-1 agonists?
The side effects of GLP-1 agonists are most commonly gastrointestinal in nature. While the exact reasons are still unclear, research suggests that they stem from a number of factors, like how long the GLP-1 agonists act in the body, their effects on the central nervous system, and their impact on general gastrointestinal functions, like how quickly your stomach empties. As long as you are on the medication, you may experience temporary side effects. The side effects, which are likely to subside over time, may include:
Starting at low doses may help circumvent these, says Kushner, who also notes that these side effects can usually be alleviated if people eat low-fat foods, smaller portion sizes, and a balanced meal plan. Even so, “because of the known side effects, the medication is always started at a low dose and periodically escalated following a fixed schedule,” he says.
Who is an appropriate candidate for GLP-1 agonists for weight loss?
The medications aren’t designed for people who just want to lose a few pounds. For a doctor to prescribe the drugs, you need to meet certain criteria. According to the NHS and National Institute for Health and Care Excellence (NICE) guidelines, GLP-1 medication can be prescribed for adults (aged 18 or over) with Type 2 diabetes or for weight management if they meet specific criteria, which typically involve a high Body Mass Index (BMI) and the presence of other weight-related health conditions. Also, those who are pregnant or nursing, planning to become pregnant, have a personal or family history of certain cancers, or have experienced angioedema, should not take GLP-1 agonists.
Lifestyle change remains the foundation for all weight loss
GLP-1 agonists are designed to be used for the chronic treatment of obesity, not something to be used in the short-term. For one, you can’t use them to jump-start your weight loss, and then attempt to maintain your weight on your own without making necessary lifestyle changes.
“People are likely to regain lost weight after stopping the medication, just as their blood pressure would increase if they stopped their anti-hypertensive medications,” says Kushner. “The drugs only work when they are taken.”
Whether or not you commit to a lifetime of taking a GLP-1 medication for weight loss, taking care of yourself goes far beyond a pill or injection. “It is important to follow a healthy diet and be as physically active as possible, since these are foundational treatments for weight loss and improved health,” says Kushner.
The WeightWatchers GLP-1 Companion Programme helps you do just that. By helping you focus on healthy habits - exercising regularly, drinking plenty of water, and getting enough protein and fibre - it helps you mitigate side effects while maximising health benefits as you lose weight on medication.
The bottom line
Ultimately, GLP-1 agonists are possible game changers in the field of medical weight management. In targeting the brain’s pathways, they’re able to lead to long-term, meaningful weight loss without sustained side effects for people with obesity who are willing to stay with the drug. Still, GLP-1s work best in partnership with healthy habits for weight management, like a nutritious diet, adequate sleep, stress management, and moderate physical activity.
The information provided in this article is intended for general informational purposes only and does not constitute individualised medical advice, diagnosis or treatment. It should not be regarded as a substitute for professional medical diagnosis or treatment from a qualified healthcare provider. Always seek the advice of your doctor or other qualified health provider with any questions you may have regarding your health, a medical condition or treatment options.