Stress, lack of exercise, genetics – the list of potential fatteners is long. One risk factor, however, receives too little attention: an unbalanced intestinal flora. The inner life of our intestines can also influence the balance – but how? This is how intestinal bacteria and obesity are connected.

Intestinal bacteria and obesity: How are they related?

The intestine: a look behind the scenes

There is a lot going on in our intestines: About 160 different bacterial species are at home in the approximately seven meter long digestive organ. And these are constantly busy supporting the immune defence and reducing food.
The largest species – Lactobacillus, Bifidobacterium, Eubacterium and Bacteroides – are present in the digestive tract of almost everyone. The situation is different with the subspecies. The composition of the bacterial culture can vary greatly from person to person. While one bacterial species can make up more than 90 percent of the total mass of one, the other only accounts for just under two percent.

Research on the relationship between obesity and intestinal flora

What do intestinal bacteria have to do with obesity? Quite a lot, as experiments with mice have already shown.1 Completely sterile mice, researchers transplanted different microbiota – in one case from persons with obesity, in the other case without.

The mice with the intestinal flora from the obese donor gained significantly more weight than the animals that had received "slender" intestinal bacteria – even though they all received the same food. The transfer of such results to humans is not possible without restrictions. However, other studies and studies with humans also suggest that a link between the type and proportion of intestinal bacteria present and the appearance of obesity is very likely.

How obesity is promoted by intestinal bacteria

Not only the "how much", but also the "what" depends on your intestinal flora. If the kilos just don't want to tumble, you may have too many fattening bacteria in you, the so-called Firmicutes.

With the Firmicutes the name is program. The Latin word "firmus" means "strong", "cutes" means "skin" – and an extra layer of tissue is exactly what these intestinal bacteria want to achieve. They prepare you for tough periods of hunger by taking even the smallest crumb of your food the maximum of calories for you and thus help you to build up a protective fat layer.

Actually, they only mean well with you – whether you think it's good is the other question. When you lose weight, you could certainly imagine something better. After all, with many Firmicutes in your intestines, you consume up to 10 percent more calories than those with a lower proportion of this type of bacteria – so it's only a matter of time before annoying fat deposits develop.

You owe your Firmicutes share not only to your genes, but also to your eating habits. Too many industrially processed foods and too little fiber are just right for this type of bacteria. They multiply diligently – and your weight increases.

Bacteroidetes – the small slimming aids in the intestine

The Firmicutes have an opponent: bacteroidetes are called the hardworking slimming aids. In comparison with the fattening bacteria, they can utilise fat worse. And exactly this weakness is in view of a weight loss aimed at their largest strength. With a large number of bacteroidetes in the intestine the probability that the energy taken up over the food is stored increased in fat cells is smaller.

Support Bacteroidetes, Decrease Firmicutes

You can actively influence the composition of your intestinal flora. With the correct nutrition you bring your intestinal bacteria into balance. If your goal is to lose weight or to reduce your body fat percentage, this means above all: to specifically support Bacteroidetes and make life difficult for Firmicutes.

But before you eat light food and counteract obesity with targeted intestinal bacteria promotion, a precise analysis cannot do any harm. Which bacteria live in your intestines? Do you have enough Bacteroidetes? Too many Firmicutes? Or is the cause of your increased body weight somewhere else? Find out with from BIOMES. Just take a small stool sample with the test kit at home and send it to the laboratory of BIOMES. After the analysis of the sample, the scientists can make precise statements about the composition of your intestinal flora.
Afterwards you will not only know all about the inner workings of your intestines, but you will also receive tips on how to specifically promote the "good" bacteria in your intestines.

1. "" Bäckhed F, Ding H, Wang T, Hooper LV, Koh GY, Nagy A, Semenkovich CF, Gordon JI. The gut microbiota as an environmental factor that regulates fat storage. PNAS 2004:101, 15718–15723,