GLP-1: Get the Facts
20 May, 2026

How do these medications actually work in the body?

GLP-1 medications generally work in two ways. First, they travel in the blood stream and attach to GLP-1 receptors in the brain. The satiety centre is stimulated to decrease appetite and craving, however they can also affect the chemoreceptor trigger zone (CTZ) which can lead to a sense of nausea. Secondly, they also work peripherally to decrease the ability of the stomach to push food down into the bowel (delayed gastric emptying). As a result of these actions, a lot of the “food noise” is reduced and one feels full quite quickly after a meal.

What steps do we take to minimise common side effects?

The commonest side effects are nausea, bloating, abdominal discomfort, headache and altered bowel habits (mostly constipation). The best way to avoid these side effects is to inject before bedtime and on a weekend. Eating little and often rather than large meals is also helpful. Avoid greasy and fried food. Hydrate well to avoid the body becoming dehydrated. Use anti-sickness medication if this persists. However if the vomiting is severe or protracted and dehydration sets in you must stop the medication. See your GP or go to A&E for IV fluids and further treatment. Mild nausea is common and usually occurs the first few days after an injection or when increasing the dose.

How do we protect muscle during the process?

The weight loss effect of these medications does not differentiate between fat and muscle, so losing some muscle mass is expected. Most research shows that the greatest losses occur from fat tissue however muscle mass is not spared. It is really important to stick to a high protein diet (approx 60-80 grams per day) and to increase your exercise levels to maintain your muscle mass. It is recommended that you take these medications as part of a program with specialist supervision and the help of a dietician. This is what we offer at weightlosssurgerykent.co.uk

Written by Mr Ahmed Hamouda

Mr Ahmed Hamouda is The Director of Weight Loss Surgery Kent. He is a highly trained and experienced Consultant Bariatric and General Surgeon.