Does the Microbiome Call the Shots?

GarlicAccording to one hypothesis, the microbiota that colonize us do not simply sit around waiting for nutrients to arrive. They have their likes and dislikes, and ways of enforcing those preferences. Like college students with Dad’s credit card, they phone out for pizza or sesame chicken and in this paradigm, we are mere delivery boys servicing a bunch of microscopic brats who may not even tip us. About a year ago, researchers from three major American universities undertook a meta-study that proved something rather startling:

Microbes influence human eating behavior and dietary choices to favor consumption of the particular nutrients they grow best on…Optimizing the balance of power among bacterial species in our gut might allow us to lead less obese and healthier lives.

Garlic enthusiasts have always existed, and the oft-repeated joke is that they are so healthy because nobody can bear to get close enough to transmit any communicable diseases. Probably every American has, at one time or another, known someone who believes raw garlic is the elixir of life, and who consequently eats a ton of it.

Maybe now we finally know why. Inulin is a fiber found in wheat, barley, leeks and—you guessed it—garlic, and research has shown that a healthy population of inner bugs enjoys these foods very much. Some scientists go so far as to call them “general fertilizers for the microbiome.” An article titled “How fast food could wreak havoc on your gut microbiome” says this:

Inulin helps encourage the gut microbiome to produce butyrate, which is an acid that feeds cells in the colon and keeps inflammation in check…Studies have also suggested that diets high in inulin lead to increases in health-promoting bifidobacteria, which break down carbohydrates to short-chain fatty acids, which may in turn decrease the risk of cancer, digestive and heart disease.

Disease prevention is wonderful, but the basic usefulness of these short-chain fatty acids is routine feeding of the cells of the intestinal lining, which don’t obtain their nutrients from the bloodstream. A paper titled “Contributors to Pediatric Obesity in Adolescence: More than just Energy Imbalance” begins with a monumental understatement:

Disentangling the etiology of pediatric obesity continues to challenge researchers.

The increasing trends in pediatric obesity are not accounted for solely by increased energy intake and decreased physical activity. Indeed, under similar conditions of energy balance, inter-individual variation in fat accumulation has been consistently noted.

It is becoming more evident that additional factors may contribute independently and/or synergistically to the increase in obesity. Such factors include (but are not limited to) metabolic programming in utero and in early childhood, the hormonal environment, endocrine disruptors…

The microbiome plays a part in metabolic programming, the hormonal environment, the effect of endocrine disruptors, and so much more. It has even been called our “second brain,” and more is discovered every day about its activities and influence. Consider these words from Dr. Pretlow about the W8Loss2Go studies:

It seems that the brain will glom onto any behavior which distracts from or eases nervousness, stress, anxiety, or tension… In the face of further stress/tension, the behavior will be repeated, which likewise eventually results in brain changes. Furthermore, the behavior becomes self-perpetuating, as trying to resist the behavior is, in itself, stressful, and stress is handled by eating. Participants in our studies reported that trying to resist taking more than the app-specified weighed amounts at meals “drove them crazy,” such that they ended up taking even more, during or after meals.

In compulsive eating, who really does the compelling? What if the feelings we interpret as stress, tension, anxiety, and being driven crazy actually arise from a pitched battle between our two brains? One brain knows better, tries to resist bad eating habits, and does not want to be destructively reprogrammed. The other brain, made up of trillions of microorganisms, contains a subpopulation of bugs that do nothing but compellingly chant “eat eat eat eat eat eat….” Is it possible?

Your responses and feedback are welcome!

Source: “Do gut bacteria rule our minds?,”, 08/15/14
Source: “How fast food could wreak havoc on your gut microbiome,”, 05/27/15
Source: “Contributors to Pediatric Obesity in Adolescence: More than just Energy Imbalance,”, 2011
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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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