A High-Fat Diet Rapidly Changes Intestinal Microbiota

Do you know the importance of the intestinal microbiota for your health? How does your diet affect these bacteria?
A High-Fat Diet Rapidly Changes Intestinal Microbiota

Last update: 27 April, 2020

The intestinal microbiota is a group of bacteria that inhabits the intestine. They have very important functions in life. First, they constitute one of the first barriers to the immune system. They’re also responsible for the assimilation of many nutrients, and the synthesis of certain vitamins.

Our gut flora consists of 100 billion bacteria from between 500 and 1,000 different species. When we’re born, our intestine is sterile. Bacteria then colonize it through food and the environment.

An altered or compromised microbiota (dysbiosis) can lead to deficits in the absorption of iron and calcium, or the development of certain diseases. In fact, in recent years studies have associated bacterial diversity with protection against certain types of complex illnesses. They’ve also shown that the microbiota may even influence muscle gain.

The influence of diet on the intestinal microbiota

According to some studies, our diet greatly influences the structure and composition of the microbiota. A diet rich in fiber and low in fat increases the population of the Prevotella genus, a type of bacteria adapted to recover energy and nutrients from foods that are rich in plant fiber.

Meanwhile, a diet rich in protein and fat increases the populations of the Bacteroides genus. Regular fiber intake increases the population of fermentative species, resulting in an increased production of short-chain fatty acids, and the prevention of complex diseases.

Furthermore, dietary fiber has protective antioxidant effects on the intestine. However, excess protein can generate metabolites that are harmful to the body, while prolonged fasting can also affect bacterial populations.

A representation of the intestinal microbiota

How to improve the quality of the intestinal microbiota

A good method to ensure the diversity of the intestinal microbiota is to add a regular consumption of probiotics and prebiotics to your diet. The first are live microorganisms that remain active in the intestine in enough quantities to alter the host’s microbiota. You can find them in foods such as yogurt.

On the other hand, prebiotics stimulates the growth of probiotics and other bacteria found in the body. An example would be dietary fiber or inulin.

A high-fat diet and the intestinal microbiota

A diet rich in fats decreases the number of Bacteroidetes and increases the number of Firmicutes and Proteobacteria. This modification of the gut flora leads to an increase in blood glucose and insulin levels on an empty stomach. It’s also possible that it causes an increase in body weight and fat and liver mass.

On the other hand, it increases the number of proinflammatory cytokines, both in plasma and in adipose, liver, and muscle tissues. This means that a high-fat diet could increase the state of inflammation and insulin resistance.

However, the daily administration of prebiotics protects against alterations of the intestinal permeability. It also lowers the markers for oxidative stress and inflammation.

Is a high-fat and low-carb diet dangerous?

Since high amounts of fat and a low fiber intake could alter the flora, it’s not unreasonable to think that high-fat diets are harmful to the body. But this doesn’t have to be the case.

A diet that’s high in poly and monounsaturated fats with a proper intake of dietary fiber, and even supplementation with pro and prebiotics, ensures that your intestinal microbiota stays healthy.

Dietary fiber will prevent changes in bacterial species resulting from an increased fat intake; this will reduce a lot of inflammation. Therefore, the production of short-chain fatty acids and vitamins will remain intact. All of which will serve as a preventive factor for the development of complex diseases.

A person eating a bowl of fresh fruit and yogurt to keep their intestinal microbiota healthy


The intestinal microbiota has a direct influence on health and disease prevention. It’s crucial to ensure the diversity of bacteria and the inclusion of dietary fiber and probiotics in our diets.

This way, we’ll also ensure the presence of fermentative strains that produce the necessary vitamins for the body, and that contribute to the functioning of the immune system.

Experts discover new functions of the microbiota every day. They can also link it to many physiological processes related to health. As a matter of fact, there are already branches of medicine dedicated exclusively to studying this phenomenon. With all of these investigations, it’s likely that in the future, our nutrition will become closely related to the type of bacteria present in our bodies.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Álvarez-Calatayud G., Guamer F., Requena T., Ascensión M., Dieta y microbiota. Impacto en la salud. Nutr Hosp, 2018. 35 (6) : 11-15.
  • Morales P., Brignardello J., Gotteland M., La microbiota intestinal: un nuevo actor en el desarrollo de la obesidad. Rev Med Chile, 2010. 138: 1020-1027.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.