By Jeff Leach

In the summer of 2008, a 26-year-old man from Shanxi Province walked into a lab at Shanghai Jiao Tong University, and 23 weeks later walked out 113 pounds lighter.

He had not participated in a clinical trial of some new secret weight loss pill, or signed up for a punishing Biggest Loser-style exercise program, nor had he been fussed over by behavioral scientists who made his plates and drinking cups smaller with each passing week.

The researchers, who were microbiologists, had simply put the man’s gut microbes on a diet.

One of the huge mysteries in studies of diet and exercise is the difference between people who get the same treatment but have remarkably different outcomes. Inevitably, some people in a study show little improvement despite weeks or even months of following what might seem like draconian changes in their normal diet and lifestyle.

Other people apparently drop weight just by getting out of bed in the morning, and also improve their circulating triglycerides, total cholesterol, and biomarkers of inflammation with apparent ease. We all know someone like this in our daily life.

But why are there such extreme differences between people?

Is your DNA to blame?

Our human genes may be involved in some cases but we generally share more than 99 percent genetic similarity with other people; more interestingly, the huge differences in peoples weight gain/loss may be driven more by the different bacteria in our intestines, which can be more than 90 percent different between one person and the next.

In addition to the familiar human genome that we inherit from our moms and dads, each of us also has hundreds of trillions of microbial symbionts, each with their own genomes. Research programs such as the Human Microbiome Project¹ have revolutionized our understanding of our microbial bodies, which outnumber our human cells 10 to one, and account for more than two pounds of your body weight. We know microbes in your gut can change profoundly throughout life, and that you can change them through diet, medications, and hygiene, for example.

We also know that how you enter this world – C-section versus vaginal birth – can impact your initial “seeding” of microbes,² which further change during breast- or formula-feeding, and what you eat later in life also affects your gut microbes and even how healthy you are as a senior citizen.³ We know that people in more traditional societies have different microbes than those in more Westernized populations,⁴ and that diet can play a role in these differences. You can also change the health prospects of a mouse overnight by changing its diet and thus its microbes.

The American Gut Project Seeks Valuable Answers

Advances in bioinformatics (fancy word for data analysis) and refinements of DNA techniques – not to mention a significant increase in computing power – is changing everything. The evidence that life events and diet can shape our gut microbes is increasing, but which direction should we nudge them? What is a healthy or optimal mix of gut microbes?

The honest answer is nobody knows (yet), but projects are underway – that you can participate in – to help us to better understand the role bacteria play in our health and lifestyle. The American Gut Project⁵ is one of the most ambitious of these projects, and I encourage you to join, to learn more about your own gut, and how it’s affecting your health. The deadline is February 2. To learn more, and for instructions on how to participate, please see Dr. Mercola’s article: “American Gut” - One of the Most Important Health Projects of the 21st Century.

The project is crowdfunded, meaning it’s funded by volunteer donations. In return, you get certain “Perks,” which include:

• A list of the dominant microbes in your gut
• Visualizations showing how you compare to the general population
• Charts showing the dominant kinds of microbes along with descriptions of what they are most associated with
• If your donation covers multiple sample kits, you may be able to see how your microbes change over time (if all the samples are from you), or how your microbes compare to those in your family members, for example

Here’s a summary of how many sampling kits you receive with your donation (The entire cost below goes directly to the Project). Kits will be mailed out starting in February, 2013: