Medical weight loss – how the treatment works

What is medical weight loss?

Medical weight loss involves the use of prescription drugs as an evidence-based complement in the treatment of overweight and obesity. Unlike methods that focus solely on calorie restriction, this form of treatment targets the underlying physiological and hormonal mechanisms that influence appetite, energy balance, and weight regulation.

Through a structured and individualized combination of pharmacological treatment and lifestyle changes, obesity is treated as a chronic disease rather than a lifestyle choice. The goal is to enable sustainable weight loss while simultaneously reducing the risk of secondary diseases such as cardiovascular disease and type 2 diabetes.

How does medical weight loss work?

Medical weight loss affects the body's own systems for appetite regulation and energy balance. Many of the medications used mimic natural satiety hormones, leading to reduced appetite and an increased feeling of fullness. This makes it easier to eat less without experiencing pronounced hunger.

The treatment also affects the gastrointestinal tract by delaying gastric emptying, which contributes to more long-lasting satiety after a meal. At the same time, there is an impact on central mechanisms in the brain, where signals linked to hunger, cravings, and reward are dampened. This can reduce frequent thoughts about food and facilitate more sustainable eating habits.

Together, these effects can create better conditions for maintaining a balanced energy level and a long-term calorie deficit.

There are also medications that work by reducing the absorption of fat in the intestine. The choice of treatment is made individually and is usually combined with structured support regarding diet, physical activity, and lifestyle habits to achieve the best possible results.

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Who can receive medical treatment for weight loss?

Medical treatment for weight loss may be relevant for adults who meet certain medical criteria, following an individual assessment by a physician. Because the treatment involves prescription medications targeting an underlying disease, a careful medical evaluation is always required.

According to current clinical guidelines, treatment may be considered for individuals who meet any of the following:

• A BMI (Body Mass Index) of 30 or higher, which is classified as obesity.
• A BMI of 27 or higher in combination with at least one weight-related complication, such as high blood pressure, sleep apnea, type 2 diabetes, or dyslipidemia (elevated blood lipids).
• A completed medical assessment, including a health declaration and relevant tests, where licensed healthcare professionals have ruled out contraindications for treatment.

If you want to understand more about the process, you can read our guide on how to get GLP-1 prescribed and which steps are included before starting treatment.

Which medications are used to lose weight?

In modern obesity treatment, medications that affect the body's hormonal regulation of appetite and energy balance are primarily used. The most common are so-called GLP-1 receptor agonists and so-called dual agonists, with active substances such as semaglutide and tirzepatide.

Semaglutide works by mimicking an endogenous hormone (GLP-1) that contributes to regulating hunger, satiety, and blood sugar. This can lead to reduced energy intake and improved control over appetite.

Tirzepatide has a similar mechanism of action but affects two hormonal signaling pathways (GLP-1 and GIP) simultaneously, which can potentially provide a broader metabolic effect.

These medications are usually administered as an injection into the subcutaneous fat once per week. The choice of preparation is based on individual medical conditions and is always made in consultation with a physician.

For those who wish to delve deeper, there is the opportunity to read more about the differences between various substances and treatment regimens.

How much weight can you lose – and what role does physical activity play?

In clinical studies, patients achieve an average weight loss of between 15 and just over 20 percent of their starting weight, but personal results always vary depending on the individual's biology and lifestyle habits. How much weight loss you specifically achieve is largely determined by how well your body responds to the treatment, your compliance with the dosing plan, and the extent to which you apply the support you receive regarding diet and physical activity.

The medication creates the biological conditions, but it is the new routines in everyday life that build the results. A long-term perspective is absolutely crucial for successful treatment because obesity is a chronic disease that requires a continuous strategy to prevent the weight from increasing again once the initial target weight is reached.

Physical activity should be seen as an aid to better health and a contributing opportunity to maintain a healthy weight in the long term.

Physical activity is a fantastic tool for metabolic health in general. Regular movement contributes to preserving muscle mass during weight loss, improving insulin sensitivity, and supporting the body's energy expenditure. This is particularly important because weight loss alone can otherwise lead to a reduction in both fat and muscle mass.

The activity should be individualized and can include both everyday movement and structured strength training. Even moderate levels of physical activity have been shown to have significant health effects and can make it easier to maintain the achieved weight over time.

Benefits of medical weight loss

By influencing hormonal signals linked to hunger and satiety, the body's biological resistance to weight loss is reduced, which can facilitate and create better conditions for sustainable results over time.

The treatment and weight loss can also contribute to improved metabolic markers, such as blood sugar control, blood lipids, and blood pressure, which in turn reduces the risk of secondary diseases linked to obesity.

When drug treatment is combined with structured and interdisciplinary care – for example, with support from a physician, coach, and if necessary a psychologist – the possibility of establishing long-term sustainable lifestyle habits is strengthened. This holistic approach, where both biological and behavioral factors are included, makes medical weight loss an effective treatment option for many patients.

Frequently asked questions about medical weight loss (FAQ)

Is medical weight loss safe?

Yes, when the treatment is prescribed and followed up by a licensed physician after a thorough and individual medical assessment, it is a safe and well-studied treatment method for the right patient group.

The healthcare provider always takes into account your medical history, potential risk factors, and ongoing treatments. The dosage is adjusted gradually to optimize efficacy and simultaneously minimize the risk of side effects, which contributes to a safe and controlled treatment process.

What side effects can occur?

The most common side effects of medical weight loss are related to the gastrointestinal tract and include nausea, diarrhea, constipation, and occasionally vomiting. These issues are usually mild to moderate, transient, and occur primarily at the start of treatment or in connection with dose increases.

Symptoms can generally be managed through individual adjustments, such as medication dosing as well as adaptations of portion sizes and dietary choices. For most patients, the discomfort gradually subsides as the body gets used to the treatment.

If necessary, follow-up and further adaptation take place in consultation with the treating healthcare provider to ensure a treatment that is as safe and well-tolerated as possible.

How long do you need to take the medicine?

Since obesity is a chronic disease, treatment often requires a long-term perspective. Many patients need a lasting or recurring maintenance treatment to counteract the body's biological tendency to return to its previous weight.

The duration of the treatment is individual and based on treatment response, achievement of goals, and potential side effects. Follow-up occurs regularly in consultation with the treating physician, who continuously evaluates the need for continued treatment or adjustment of the treatment plan.

Do I need to change my diet when taking the medication?

Yes, the treatment provides the best effect in combination with a nutritious and balanced diet as well as regular physical activity. To lose weight, the body needs to be in an energy deficit, but the medication facilitates this by regulating appetite and reducing spontaneous energy intake.

The composition of the diet is particularly important during weight loss, where an adequate protein intake in combination with strength training contributes to preserving muscle mass while the body primarily reduces fat mass.

The medication helps to create the conditions, but it is the dietary habits that determine the nutritional quality and thus affect both health and body composition. A structured and sustainable dietary regimen is therefore a central part of the treatment and should be adapted to individual needs and goals.

What happens if you stop taking GLP-1?

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When treatment with GLP-1 is discontinued, the body's appetite regulation often gradually returns to its original state. This means that hunger, satiety signals, and food cravings may increase, making it more difficult to maintain a lower energy intake.

Since obesity is a chronic disease, there is an increased risk of weight gain after stopping treatment. The extent of this risk varies between individuals and is influenced, among other things, by established lifestyle habits and how long the treatment has lasted.

Can I get the medicine if I only want to lose a few kilos?

Medical weight loss is intended for the treatment of overweight and obesity according to established medical criteria. Prescription is based on clear guidelines and following an individual medical assessment.

The treatment is not intended for minor, cosmetic weight loss, but is aimed at individuals where weight poses a medical risk or is linked to secondary diseases. The goal is to treat an underlying disease and improve long-term health.

References

World Health Organization (WHO). Obesity and overweight
https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight

American Journal of Clinical Nutrition. A descriptive study of individuals successful at long-term maintenance of substantial weight loss.
https://pubmed.ncbi.nlm.nih.gov/9250100/

The New England Journal of Medicine (NEJM). Once-Weekly Semaglutide in Adults with Overweight or Obesity
https://www.nejm.org/doi/full/10.1056/NEJMoa2032183

The New England Journal of Medicine (NEJM). Tirzepatide Once Weekly for the Treatment of Obesity
https://www.nejm.org/doi/full/10.1056/NEJMoa2206038

European Medicines Agency (EMA). Wegovy
https://www.ema.europa.eu/en/medicines/human/EPAR/wegovy

European Medicines Agency (EMA). Mounjaro
https://www.ema.europa.eu/en/medicines/human/EPAR/mounjaro