Gut Bacteria Determines Ability to Lose Weight and Keep it Off

by Case Adams

gut bacteria

Ever wonder why one person will gain weight so easily while another easily remains skinny?

Certainly a lot has to do with our diets, but given the same diet, some people simply have a greater tendency to gain weight. New research from Kings College in the UK and Cornell University – funded by the National Institutes of Health – has found the key to this individualistic metabolism: Our gut bacteria – defined genetically speaking as our microbiome.

Microbiome research confirms weight loss link to gut bacteria

The researchers conducted a multi-pronged study that first investigated the relationship between ones genes and their gut bacteria. This was done by testing fecal samples from 416 sets of twins – both identical (monozygotic) and non-identical (dizygotic) twins.


The research found that identical (monozygotic) twins were most likely to also share the same types of gut bacteria. The fecal samples allowed the researchers to run DNA scans – which analyze the range of genes.

The research also found that a particular family of bacteria dominated the microbiota of those twins that had a low body mass index (BMI). The predominant family found among low-BMI people is called Christensenellaceae.

And one of the prominent bacteria species found among the skinnier people was Christensenella minuta.

Ones microbiota is the range of different species of gut bacteria – in this case found by analyzing the feces.

Implications of microbiome heredity

And because parents will typically pass on their microbiota to their children, this also means that weight management abilities are also somewhat inherited. But because our microbiota is also determined by our diets, this also means that our diets and the diets of our parents are connected to our ability to lose weight.

Proving the gut bacteria link

To prove that this particular species of gut bacteria indeed could affect ones weight management, the researchers then extracted the species of Christensenella minuta, and produced a cultured “amendment” that was then given to mice.


The research found that mice given the Christensenella minuta amendment were able to easily lose weight and keep the weight down.

Dr. Timothy Spector, a professor of genetics at King’s College, commented about the study in a King’s College press release:

“Our findings show that specific groups of microbes living in our gut could be protective against obesity – and that their abundance is influenced by our genes. The human microbiome represents an exciting new target for dietary changes and treatments aimed at combating obesity.”

Dr. Spector also introduced a new crowd-funding project that will test human microbiomes via a large-scale internet study called the British Gut Project (

‘Twins have been incredibly valuable in uncovering these links – but we now want to promote the use of microbiome testing more widely in the UK through the British Gut Project. This is a crowd-sourcing experiment that allows anyone with an interest in their diet and health to have their personal microbes tested genetically using a simple postal kit and a small donation via our website. We want thousands to join up so we can continue to make major discoveries about the links between our gut and our health.”

The ramifications of this new study are broad. While it certainly does not mean that we can ignore the need for a healthy diet, understanding how our probiotics affect not only our health and our immunity but also our ability to lose the pounds and keep them off brings new hope to the epidemic of obesity among Western countries.

This was confirmed by Dr. Ruth Ley, Cornell University professor:

“Up until now, variation in the abundances of gut microbes has been explained by diet, the environment, lifestyle, and health. This is the first study to firmly establish that certain types of gut microbes are heritable — that their variation across a population is in part due to host genotype variation, not just environmental influences. These results will also help us find new predictors of disease and aid prevention.”

Other microbiome research confirms gut bacteria affect our weight along with diseases

Other research has confirmed the link between body mass index and the microbiome. For example, University of Manitoba researchers recently linked childhood microbiome to not only BMI, but glucose control and a range of inflammatory diseases.


As explained at length in The Ancestors Diet, microbiome research has also indicated a link between disease and our gut bacteria – and healthy or not-so-healthy diets among our ancestors and not so healthy diets. In other words, microbiota can indicate what our healthiest ancestors ate, as well as indicate which diets among later ancestors were not so healthy.


Goodrich JK, Waters JL, Poole AC, Sutter JL, Koren O, Blekhman R, Beaumont M, Van Treuren W, Knight R, Bell JT, Spector TD, Clark AG, Ley RE. Human Genetics Shape the Gut Microbiome. Cell, 2014; 159 (4): 789 DOI: 10.1016/j.cell.2014.09.053

The British Gut Project

Munyaka PM, Khafipour E, Ghia JE. External influence of early childhood establishment of gut microbiota and subsequent health implications. Front Pediatr. 2014 Oct 9;2:109. doi: 10.3389/fped.2014.00109.