Anyone being treated with weight loss medication such as GLP-1 analogs (e.g. semaglutide, liraglutide) and related active ingredients such as tirzepatide will be familiar with the situation: hunger is reduced, portions automatically become smaller and food intake decreases. On the one hand, this is helpful for weight loss – on the other hand, it increases the risk of missing out on important nutrients and fiber. They play a central role in intestinal health, digestion and satiety.
Why dietary fiber is so important
Dietary fibers are indigestible components of plant foods. Although they do not provide any calories, they have many positive effects:
- They promote intestinal activity by increasing the volume of stool and shortening the passage time (prevention of constipation).
- They serve as food for the intestinal microbiota. Bacteria ferment soluble fiber into short-chain fatty acids such as butyrate, which have an anti-inflammatory effect and strengthen the intestinal barrier.
- They contribute to blood sugar regulation because they delay gastric emptying and flatten the rise in glucose.
- They promote satiety as they bind water, increase the volume in the stomach and strengthen hormonal satiety signals.
The German Nutrition Society (DGE) recommends that adults consume at least 30 g of fiber per day – a target that many people don’t reach anyway. It is a particular challenge when food intake is reduced.
Dietary fiber during GLP-1 therapy: double benefit
GLP-1 drugs themselves have an effect on satiety and gastric emptying. Here, dietary fiber can enhance their effect:
- More volume despite smaller portions: If you can only eat a small amount, you should choose foods that contain as much fiber as possible – e.g. whole grain products, legumes, vegetables and berries.
- Additional support for the intestinal flora: As the amount of food decreases, the intestinal bacteria also receive less “replenishment”. Fiber-rich foods prevent the diversity of the microbiota from decreasing.
- Long-term weight stability: Studies show that a high-fiber diet is associated with a lower risk of weight gain and better blood sugar levels.
Typical challenges and solutions
Many patients report that the small meals barely provide them with 30 g of fiber. Practical tips:
- Choose fiber-rich basics: Instead of white bread, choose wholemeal, instead of white pasta, wholemeal pasta.
- Incorporate pulses: Chickpeas, lentils or beans are high in protein and fiber – ideal for small portions with high nutritional value.
- Consciously combine fruit and vegetables: Berries, pears, carrots, broccoli or zucchini provide a lot of fiber with a low calorie density.
- Use nuts & seeds (e.g. linseed, chia seeds, almonds) as a topping.
- Fiber supplements can be useful in individual cases, but should only be used after consultation with specialists, as they can also cause flatulence or abdominal pain if increased too quickly.
Conclusion
Dietary fibres are not just “fillers”, but an active component of a healthy diet – especially when less food is consumed due to medication. They promote intestinal health, prolong satiety and help to make the diet nutritious despite small portions.
If you are using weight loss medication, you should therefore consciously include fiber in your diet: small portions with a big effect.
Sources
- German Nutrition Society (DGE). Dietary fiber intake. DGE 2023
- Slavin JL. Dietary fiber and body weight. Nutrition. 2005;21(3):411-418. PubMed
- Makki K, Deehan EC, Walter J, Bäckhed F. The Impact of Dietary Fiber on Gut Microbiota in Host Health and Disease. Cell Host Microbe. 2018;23(6):705-715. PubMed
- Reynolds A et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019;393:434-445.
- Blundell J et al. Effects of liraglutide on appetite and energy intake in subjects with obesity. Int J Obes. 2019;43:1741-1751. PubMed