GLP-1 for Weight Loss: Everything You Need to Know Before You Start

In recent years, GLP-1 receptor agonists (GLP-1 RAs) have gained major attention for their role in weight loss. These medications were originally developed for type 2 diabetes but have shown powerful effects in reducing body weight in people with obesity.

Unlike fad diets or supplements, GLP-1 works by targeting the hormones that regulate appetite, satiety, and metabolism (NCBI, 2024). Before starting treatment, it’s essential to understand how they work, their benefits, risks, and realistic expectations.

Medications that include Peptide-1 (GLP-1) are natural gut hormones released after eating. Its main functions include:

• Stimulating insulin secretion in response to food

• Lowering blood sugar

• Slowing gastric emptying, helping you feel fuller for longer

• Acting on the brain to increase satiety and reduce hunger

When taken as medication, GLP-1 receptor agonists mimic these natural effects — making it easier to eat less, reduce cravings, and manage weight (NCBI, 2024).

Large studies confirm the effectiveness of GLP-1 medications:

• A meta-analysis found GLP-1 led to meaningful reductions in body weight, BMI, and waist circumference compared with placebo (PubMed, 2024).

• In people without diabetes, weight loss is often greater than in those with diabetes, likely due to fewer metabolic barriers (NCBI, 2024).

• Clinical trials with newer medications show 15–20% body weight reduction over 12–18 months (NCBI, 2024).

• However, once treatment stops, many individuals regain much of the lost weight within a year (NCBI, 2024).

• Beyond weight loss, GLP-1 therapies improve blood sugar, cholesterol, and blood pressure, supporting better metabolic health overall (Cureus, 2024).

Common side effects:

• Nausea, vomiting, diarrhoea, constipation (Harvard Health Publishing, 2023).

Other potential risks:

• Facial fat loss due to rapid weight reduction (Harvard Health Publishing, 2023).

• Gallstones and gallbladder issues, sometimes linked to rapid fat loss (NCBI, 2024).

• Contraindicated in people with a personal/family history of medullary thyroid cancer or MEN2 (NCBI, 2024).

• Reports of lean muscle mass loss during treatment, highlighting the need for exercise and adequate protein (JAMA Network, 2023).

• The FDA has warned against buying unapproved or compounded GLP-1 drugs online due to safety concerns (FDA, 2023).

Most side effects improve over time, but GLP-1s should always be prescribed and monitored by a qualified healthcare professional.

If you’re considering GLP-1 therapy, here are the essentials:

1. Medical evaluation first — rule out contraindications such as thyroid cancer history or pancreatitis.

2. Set realistic expectations — weight loss is steady but not instant.

3. Lifestyle support is essential — nutrition, exercise, and behaviour change improve results.

4. Plan for long-term therapy — weight regain is likely if treatment is stopped abruptly (NCBI, 2024).

5. Understand cost and coverage — GLP-1 drugs can be expensive and may not always be covered by insurance.

GLP-1 works best when paired with healthy habits.

Dietary tips:

• Prioritise high-protein meals to preserve lean muscle (JAMA Network, 2023).

• Include fibre-rich foods for better satiety and gut health.

• Avoid high-fat meals initially, as they can worsen nausea (Harvard Health Publishing, 2023).

Exercise recommendations

• Strength training at least twice a week to maintain muscle.

• Cardio activities such as brisk walking or cycling for heart health.

Lifestyle habits

• Get adequate sleep — poor sleep increases cravings.

• Manage stress to avoid emotional eating.

Realistic Expectations & What Happens After Stopping

• Most people lose 10–20% of body weight on GLP-1 therapy (NCBI, 2024).

• Weight loss usually plateaus after several months.

• If treatment is stopped, much of the lost weight can return (NCBI, 2024).

• Long-term maintenance strategies — whether continuing therapy, adjusting lifestyle, or tapering doses — are critical.

• Cureus (2024) peptide-1 (GLP-1) receptor agonists: Exploring their impact on diabetes, obesity, and cardiovascular health through a comprehensive literature review.

• Harvard Health Publishing (2023) GLP-1 diabetes and weight-loss drug side effects: Ozempic face and more. Harvard Medical School. JAMA Network (2023) I am taking a GLP-1 weight-loss medication—what should I know? JAMA Internal Medicine.

• JAMA Network (2023) I am taking a GLP-1 weight-loss medication—what should I know? JAMA Internal Medicine.

• National Center for Biotechnology Information (2024) The expanding role of GLP-1 receptor agonists: a narrative review of obesity management.

• PubMed (2024) Efficacy of GLP-1 receptor agonists on weight loss, BMI, and waist circumference: a meta-analysis. PubMed

• U.S. Food & Drug Administration (2023) FDA’s concerns with unapproved GLP-1 drugs used for weight loss. FDA.