Have you ever wondered why some people can eat copious amounts of food and never put on a pound while others seem to just look at food and they can no longer button their pants?
Contrary to popular belief, this is not necessarily a matter of genetics, and there is a scientific explanation. The answer lies in not how much someone is eating, but rather the composition of their gut bacteria and how the types of food they’re eating is affecting and changing that bacteria.
As human beings we have more bacteria in our body than we have cells. The human intestinal tract alone is home to more than 100 trillion bacteria which serve as our first line of defense against intruders and all disease. In fact, bacteria are absolutely crucial to our survival and play a primary role in not only boosting our immune system, but in also regulating insulin sensitivity, metabolism, and brain function, among other things.
This community of bacteria in your body is known as your microbiome, and it has become a hot topic lately. This is because those in the medical and scientific world are beginning to realize that these little critters are responsible for, and directly related to, just about every disease known to man. They’ve also come to understand that gut bacteria are inextricably tied to weight gain and the rise in obesity(1-4).
Microbiome Differs In Obese And Thin People
Your microbiome interacts and actually “talks” to cells in your body, and has an impact on your gene expression – whether good genes kick in to protect you from disease or bad genes are left unchecked and cause disease to take over.
Scientists were surprised to discover that bacteria found in an obese person’s body is completely different than that found in a thin person. Not only do thin people have more beneficial gut bacteria, but they also have a far more complex and diverse range of bacteria species throughout their digestive system. This microbiome diversity assists thin people in warding off diseases such as cancer, heart disease, diabetes, and liver disease, as well as sleep, neurological, and autoimmune disorders. In addition, this range of beneficial bacteria actually prevents thin people from becoming obese and, when transplanted into an obese person, causes the obese person to lose weight and alters their metabolism and genes.
Changing Your Microbiome To Prevent Disease And Obesity
Although the quantity and quality of your microbiome is affected by many things, almost every single one of them is completely within your control. The following items most strongly affect the health and diversity of your microbiome:
To maintain or restore a healthy microbiome doctors often recommend the use of prebiotics and probiotics – supplements that replace several types of beneficial bacteria. When the situation is dire doctors may even suggest extreme surgical intervention, using fecal transplants and bariatric surgery as a means to restore healthy and balanced bacteria levels. While this is all well and good, an often overlooked, extremely effective, and safe method is to simply change a person’s eating habits.
The microbiome can change rapidly given the right nourishment, as has been proven in scientific studies. In fact, the consumption of even one meal has the ability to radically shift gut bacteria, which can either be a good thing or a bad thing, depending on what it is you choose to eat.
Dietary Choices That Alter Your Gut Bacteria
Scientists have confirmed that nurture (lifestyle) is far more important than nature (genetics) when it comes to the health and diversity of the microbiome by studying and, in some cases, switching the diets of two biologically similar groups of subjects. In one such study, scientists recruited and evaluated two sets of men – an African American group and a rural African group(5). These men were chosen for the study due to the fact that an exceptionally large number of African American men develop colon cancer each year, while their rural African counterparts experience an extremely low incidence of colon cancer. In fact, 65 out of every 100,000 African American men are diagnosed with colon cancer annually, while less than five out of every 100,000 rural African men develop the disease over the same period of time. Scientists were curious about the role that diet plays in these disease rates as they learned that the African American men consumed 2-3 time the amount of animal protein and fat and far less fiber and carbohydrates than the men from the rural African village.
In reviewing fecal samples, the 2014 study showed that the microbiome was vastly different between the two groups of men, with the African American men showing much higher biomarkers for cancer and a reduced ability to suppress secondary bile acids, which are carcinogenic.
Researchers switched the diets of the two sets of men for a period of only two weeks, which produced astonishing results confirmed by fecal samples and colonoscopy. When placed on the traditional, rural African diet – primarily vegetarian, low in fat, and high in fiber – the African American men showed an increase in the number of beneficial bacteria in the gut, as well as more microbial diversity. In addition, the African American men began to exhibit an increase in short-chain fatty acids such as butyrate, which is essential to colon health and has anti-carcinogenic and anti-inflammatory properties. Alternatively, while consuming the traditional Western diet – largely animal-based, high in fat, and low in fiber – the rural African men experienced the exact opposite effect and developed symptoms and biological markers consistent with an increased risk for colon cancer.
An earlier study in 2010 resulted in similar findings in the gut bacteria of healthy children, ages one to six years old, when comparing those living in western Europe to those living in a rural African village(6). As with the study of African men, the children presented with completely disparate gut bacteria, which was traced to their diet. The European children consumed foods similar to the African American men – high in animal protein and fat – while the rural African children consumed the diet of their ancestors – “high in starch, fiber, and plant polysaccharides, and predominantly vegetarian.”
In the course of their research, scientists noted that the microbiome disparity was more pronounced in children over the age of one. Based on data collected, this age-related shift was attributed to a change in diet at that time of the child’s life – from breast milk to that of dairy products and solids, including meats and processed foods.
The latter study, as well as additional research(7), suggests that early intervention is important in preventing children from forming a microbiome that promotes obesity and disease later in life. However, all of the studies should serve to reassure us and provide us with a level of peace in knowing that it’s never too late to begin reshaping the health of our gut bacteria to prevent and reverse disease.
- Da Silva, S. T., C. A. Dos Santos, and J. Bressan. “Intestinal Microbiota; Relevance to Obesity and Modulation by Prebiotics and Probiotics.” Nutricion Hospitalaria. July/August 2013. http://www.ncbi.nlm.nih.gov/pubmed/23889619.
- Halmos, T., and I. Suba. “Physiological Patterns of Intestinal Microbiota. The Role of Dysbacteriosis in Obesity, Insulin Resistance, Diabetes and Metabolic Syndrome.” National Center for Biotechnology Information. January 3, 2016. doi:10.1556/650.2015.30296.
- Yang, J-Y, Y-S Lee, Y. Kim, S-H Lee, S. Ryu, S. Fukuda, K. Hase, C-S Yang, H. S. Lim, M-S Kim, H-M Kim, S-H Ahn, B-E Kwon, H-J Ko, and M-N Kweon. “Gut Commensal Bacteroides Acidifaciens Prevents Obesity and Improves Insulin Sensitivity in Mice.” Mucosal Immunology, April 27, 2016. doi:10.1038/mi.2016.42.
- Boulangé, Claire L., Ana Luisa Neves, Julien Chilloux, Jeremy K. Nicholson, and Marc-Emmanuel Dumas. “Impact of the Gut Microbiota on Inflammation, Obesity, and Metabolic Disease.” Genome Medicine 8, no. 1 (April 20, 2016). doi:10.1186/s13073-016-0303-2.
- O’Keefe, Stephen J. D., Jia Li, Leo Lahti, Junhai Ou, Franck Carbonero, Khaled Mohammed, Joram M. Posma, James Kinross, Elaine Wahl, Elizabeth Ruder, Kishore Vipperla, Vasudevan Naidoo, Lungile Mtshali, Sebastian Tims, Philippe G. B. Puylaert, James Delany, Alyssa Krasinskas, Ann C. Benefiel, Hatem O. Kaseb, Keith Newton, Jeremy K. Nicholson, Willem M. De Vos, H. Rex Gaskins, and Erwin G. Zoetendal. “Fat, Fibre and Cancer Risk in African Americans and Rural Africans.” Nature Communications Nat Comms 6 (April 28, 2015): 6342. doi:10.1038/ncomms7342.
- Filippo, C. De, D. Cavalieri, M. Di Paola, M. Ramazzotti, J. B. Poullet, S. Massart, S. Collini, G. Pieraccini, and P. Lionetti. “Impact of Diet in Shaping Gut Microbiota Revealed by a Comparative Study in Children from Europe and Rural Africa.” Proceedings of the National Academy of Sciences 107, no. 33 (August 02, 2010): 14691-4696. doi:10.1073/pnas.1005963107.
- Sanchez, Marina, Shirin Panahi, and Angelo Tremblay. “Childhood Obesity: A Role for Gut Microbiota?” International Journal of Environmental Research and Public Health IJERPH 12, no. 1 (December 23, 2014): 162-75. doi:10.3390/ijerph120100162.