2024-08-21 22:50:34
Special fiber
Why our gut loves yesterday’s pasta
Updated on 21.08.2024 – 13:02Reading time: 4 min.
It is supposed to help you lose weight and is really good for your gut: resistant starch. But what can the fiber really do – and what can’t it do?
When cooked pasta cools down, it loses calories. Does that sound too good to be true? There is actually a grain of truth in this statement. When pasta cools down, so-called resistant starch forms. Our small intestine cannot digest it and therefore cannot extract energy from it.
But you shouldn’t necessarily expect pasta or potato salads to be a shortcut to losing weight. But there is another reason why we should regularly eat foods with resistant starch. Three experts explain the background.
To understand resistant starch, you first have to look at starch in general. Biochemically, it is a so-called polysaccharide and is a carbohydrate. “It occurs naturally in foods such as potatoes, bread, pasta, rice, grains, seeds, pulses and corn,” says Birgit Blumenschein, dietician and medical educator. “Heating and chewing break down the starch molecules and make the starch in foods “digestible” for us humans, i.e. usable.”
Resistant starch, however, is a special form of starch. It is created when cooked foods or dishes are left to cool down. For example, pasta, rice or potatoes in order to prepare salads. “When cooled and reheated, the starch molecules rearrange themselves so that they can no longer be broken down by the digestive enzymes,” says Marcus Kever, a trainee dietician at the University Hospital Essen.
“Resistant” means resistant to the digestive enzymes in the small intestine. The job of these enzymes is to break down food components and make them usable for the body. And what happens if nutrients cannot be digested in the small intestine – such as fiber? These substances end up in the large intestine, where the stool is prepared.
Resistant starch is therefore a soluble fiber, as Kever says. But that doesn’t mean that nothing happens to the fiber in the large intestine. The bacteria there metabolize it, which creates health-promoting fatty acids, for example. But more on that later.
At most, partially. “The idea of losing weight comes from the fact that resistant starch is not digested and the calories are thus expelled with the stool,” says Birgit Blumenschein.
Basically, foods with a higher proportion of resistant starch provide the body with slightly less energy. And they keep you full for longer. “Formally, the reduced feeling of hunger could lead to a slight loss of weight,” says Birgit Terjung. She is a gastroenterologist, nutritional doctor and media spokesperson for the German Society for Gastroenterology, Digestive and Metabolic Diseases (DGVS).
But research still has unanswered questions. “According to current knowledge, significant weight loss cannot be achieved through increased consumption of resistant starch,” is Terjung’s assessment. Many factors play a role in successful weight loss.
- Read also: Lose weight quickly – tips that really help
The consumer advice center points out that only a small part of the starch is converted when the potatoes are cooled. According to this, 100 grams of cooled potatoes contain just 3.5 kilocalories less than freshly cooked ones. To put this into perspective: 100 grams of cooked potatoes contain around 70 kilocalories. And if the cooled potatoes or pasta are served with fatty mayonnaise in a salad, the few calories saved are quickly made up for anyway.
“Even if resistant starch does not directly help you lose weight, it does have a large and extremely positive effect on the intestines and the bacteria that live in them,” says Marcus Kever.
It is a source of food for the colon bacteria. They digest the resistant starch. “The broken down molecular chains produce short-chain fatty acids such as butyric acid, so-called butyrates,” explains Kever. They support the colon mucosa and promote optimal defense function, thus strengthening the intestinal immune system.
A fatty liver is a serious disease. It is usually caused by an unhealthy lifestyle with lots of sugar and fat, as well as little exercise. Certain medications or excessive alcohol consumption also play a role. However, it has been suspected for several years that a disturbance of the intestinal flora also contributes to the development of a fatty liver.
Researchers from China, Germany and Finland have discovered that daily intake of resistant starch can significantly reduce fat deposits in the liver of fatty liver patients. They attribute this to a change in the intestinal flora. You can find more information about the study here.
To get the most benefit, you first need to know that resistant starch is not only found in cooled pasta and potatoes. “Resistant starch also occurs naturally in some foods,” says Birgit Terjung. It is naturally found in pulses, especially white beans, coarsely ground grains and slightly ripe bananas.