We all know how it is: some people feel full after just a small snack, while others need a whole meal before they even think about stopping. It comes as no surprise that such differences are also noticeable in obesity therapy – losing weight is complex, and finding the right medication is often a gamble. Looking at simple indicators such as body mass index is often of little help here. Two people with the same BMI of 35 kg/m² can react completely differently to the same medication. The good news is that a genetic test might help here.
Full? It depends on the person
Researchers at the Mayo Clinic had nearly 800 people with obesity consume lasagne, pudding and milk until they were full. The result: the range was from 140 to over 2,000 calories.
Classic parameters such as body weight, hormones or age hardly explained these differences. The trail led to genetics. The researchers combined variants from ten genes associated with eating behaviour and used them to develop the Calories to Satiation Genetic Risk Score (CTS-GRS). The principle: a blood or saliva sample is sufficient to determine an individual’s satiety threshold.
From ‘hungry brain’ to ‘hungry gut’
And what does this mean in practice?
· Patients with a high satiety threshold (‘hungry brain’) – i.e. those who need large portions to feel full – benefit more from phentermine topiramate. The drug works precisely by effectively limiting portion size.
· Patients with a low satiety threshold (‘hungry gut’) – who tend to snack frequently – responded better to liraglutide (Saxenda®) in the studies. Liraglutide is a GLP‑1 analogue that not only curbs appetite, but also reduces meal frequency – thus addressing the typical pattern of ‘hungry gut’.
This makes it clear that there is no such thing as ‘one effective weight loss injection for all’. Knowing in advance which substance works best saves patients the frustrating experience of months of therapy without results – and allows for more targeted advice.
Precision instead of trial and error
This is an attractive idea for everyday clinical practice: no long periods of trial and error, but a clear indication of which preparation is appropriate. The test is already being used in numerous clinics in the USA. Expansions are planned – for example, for semaglutide (Ozempic®, Wegovy®) – as well as the integration of microbiome and metabolome data. Whether and when the procedure will also be available in this country is still open.
What are your thoughts on this topic? Would you like to learn more about it? You can find the scientific publication on this topic here:
Cifuentes, Lizeth et al. Genetic and physiological insights into satiation variability predict responses to obesity treatment. Cell metabolism vol. 37,8 (2025): 1655–1666.e5.