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Four Ways to Get Firm by Lowering Firmicutes

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The Biggest Myth About Obesity

One of the biggest myths about obesity is that it’s caused by laziness or indulgence. It’s not. It’s caused by your body reacting to stressors. In response to stress, your body will store food to prepare for famine, and you will gain weight. Some stressors are obvious, but many are not. Some are as silent and invisible as the bacteria in our intestines.

In a startling study,1Vijay-Kumar M, Aitken JD, Carvalho FA, et al. Metabolic syndrome and altered gut microbiota in mice lacking Toll-like receptor 5. Science. 2010;328(5975):228-231. https://doi.org/10.1126/science.1179721 Dr. Gewirtz at Cornell University showed that the weight of mice could be changed by over 15 percent just by shifting their intestinal bacteria. Along with weight changes, the bacteria present changed the mice’s chemistry in ways that could predict heart disease, high blood pressure, and risks for diabetes.

Related work2Duncan SH, Lobley GE, Holtrop G, et al. Human colonic microbiota associated with diet, obesity, and weight loss. Int J Obes (Lond). 2008;32(11):1720-1724. https://doi.org/10.1038/ijo.2008.155 has shown this same connection to gut bacteria also exists in humans. In fact, transplanting bacteria from the intestinal tracts of obese humans has been shown to trigger obesity in normal-weight mice.3Fei N, Zhao L. An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice. ISME J. 2013;7(4):880-884. https://doi.org/10.1038/ismej.2012.153

Understanding Intestinal Bacteria

Scientist places slide under microscope

First, it’s important to realize that 99 percent of our gut bacteria are unable to use oxygen. Bacteria that can’t use oxygen are called anaerobes. This is important because foods like sauerkraut and yogurt—as well as probiotic supplements—only contain bacteria that live in oxygen. These foods and supplements have little or no effect on the anaerobes that run the show.

Of the many types of anaerobes, the two that are most directly involved with obesity are the Bacteroidetes and Firmicutes. Most studies have shown that the more Bacteroidetes you have (compared to your Firmicutes), the leaner you will be. So, if you want to be firm, you want more Bacteroidetes and fewer Firmicutes.

How Gut Bacteria Affect Body Weight

The reason these bacteria affect our weight is that they regulate how much fat we absorb. Imagine identical twins eating exactly 2,000 calories but with different ratios of Bacteroidetes to Firmicutes. The one with a higher ratio of Firmicutes to Bacteroidetes will absorb more calories than the other and be more apt to gain weight while eating the exact same diet.4Turnbaugh PJ, Hamady M, Yatsunenko T, et al. A core gut microbiome in obese and lean twins. Nature. 2009;457(7228):480-484. https://doi.org/10.1038/nature07540

In light of the growing rates of obesity, a good question to ask would be, “What is causing these bacteria to shift in ways that would lead to weight gain?

One explanation is the remarkable changes in our lifestyle over the past few decades. Today we use more antimicrobial soaps and hand sanitizers, are exposed to more environmental pollutants, and live under higher amounts of stress.

Stress Affects Bacteria and Weight Management

It’s easy to see the effect of hand sanitizers and environmental pollutants. Antimicrobial soaps and hand sanitizers are problematic because they kill good bacteria as well as bad ones. Environmental pollutants are toxic to good bacteria, just as they’re toxic to us. However, the connection of stress to bacteria is less obvious. How does stress affect bacteria?

Mental and emotional stress triggers the release of adrenal stress hormones, like cortisol and adrenaline. These stress hormones act on the brain and stimulate the vagus nerve, an important nerve that forms a kind of circuit between the brain and the heart, lungs, and—tellingly—the gut. Stress reduces the blood supply needed to properly digest foods and manage the balance of bacteria. And this tie between your brain and gut is a two-way street, because stress hurts your digestion, and poor digestion makes you feel more stressed. When this vicious cycle gets rolling, your Bacteroidetes are reduced, and you gain weight more easily.

You Can Promote a Healthy Gut

Diet, nutrition, and consistency are three of the best ways to boost gut health.

  1. Eat a high-fiber diet with good carbs. Because Firmicutes are needed to absorb fats, higher fat diets cause you to have more of them, leading to weight gain.5de La Serre CB, Ellis CL, Lee J, Hartman AL, Rutledge JC, Raybould HE. Propensity to high-fat diet-induced obesity in rats is associated with changes in the gut microbiota and gut inflammation. Am J Physiol Gastrointest Liver Physiol. 2010;299(2):G440-G448. https://doi.org/10.1152/ajpgi.00098.2010
  2. Avoid sugars and processed carbs. Firmicutes are so well-suited to grow on sugars that they’re known to grow rampantly in factories that process sugar cane into table sugar.6Sharmin, F., Wakelin, S., Huygens, F. et al. Firmicutes dominate the bacterial taxa within sugar-cane processing plants. Sci Rep. 2013;3:3107. https://doi.org/10.1038/srep03107
  3. Raise your intake of beans. Beans are among the very best foods to raise your Bacteroidetes.7Maslowski KM, Mackay CR. Diet, gut microbiota and immune responses. Nat Immunol. 2011;12(1):5-9. https://doi.org/10.1038/ni0111-5 If you can’t digest beans, it’s a likely sign you have too few Bacteroidetes. But rather than avoid beans completely, studies8Winham DM, Hutchins AM. Perceptions of flatulence from bean consumption among adults in 3 feeding studies. Nutr J. 2011;10:128. Published 2011 Nov 21. https://doi.org/10.1186/1475-2891-10-128 show that slowly adding beans to your diet helps ease symptoms. To train your body to digest beans well, add one tablespoon of pinto beans daily to the evening meal for two weeks. After two weeks, most people can digest more typical amounts.
  4. Sleep and eat on a regular schedule. Cutting-edge data9Thaiss CA, Zeevi D, Levy M, et al. Transkingdom control of microbiota diurnal oscillations promotes metabolic homeostasis. Cell. 2014;159(3):514-529. https://doi.org/10.1016/j.cell.2014.09.048 show that our intestinal bacteria have a rhythm that changes throughout the day, just like our sleep–wake cycle. Shift work, jet lag, and erratic mealtimes can hurt our good bacteria just as antibiotics can.
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New Thinking About Health and Weight Management

The notion that you could only be healthy with strenuous effort and deprivation is long gone. Today’s perspective on health supports a much more holistic approach. Staying healthy, lean, and energized are the results of being at peace—and in sync with the world around you.

Footnotes

  • 1
    Vijay-Kumar M, Aitken JD, Carvalho FA, et al. Metabolic syndrome and altered gut microbiota in mice lacking Toll-like receptor 5. Science. 2010;328(5975):228-231. https://doi.org/10.1126/science.1179721
  • 2
    Duncan SH, Lobley GE, Holtrop G, et al. Human colonic microbiota associated with diet, obesity, and weight loss. Int J Obes (Lond). 2008;32(11):1720-1724. https://doi.org/10.1038/ijo.2008.155
  • 3
    Fei N, Zhao L. An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice. ISME J. 2013;7(4):880-884. https://doi.org/10.1038/ismej.2012.153
  • 4
    Turnbaugh PJ, Hamady M, Yatsunenko T, et al. A core gut microbiome in obese and lean twins. Nature. 2009;457(7228):480-484. https://doi.org/10.1038/nature07540
  • 5
    de La Serre CB, Ellis CL, Lee J, Hartman AL, Rutledge JC, Raybould HE. Propensity to high-fat diet-induced obesity in rats is associated with changes in the gut microbiota and gut inflammation. Am J Physiol Gastrointest Liver Physiol. 2010;299(2):G440-G448. https://doi.org/10.1152/ajpgi.00098.2010
  • 6
    Sharmin, F., Wakelin, S., Huygens, F. et al. Firmicutes dominate the bacterial taxa within sugar-cane processing plants. Sci Rep. 2013;3:3107. https://doi.org/10.1038/srep03107
  • 7
    Maslowski KM, Mackay CR. Diet, gut microbiota and immune responses. Nat Immunol. 2011;12(1):5-9. https://doi.org/10.1038/ni0111-5
  • 8
    Winham DM, Hutchins AM. Perceptions of flatulence from bean consumption among adults in 3 feeding studies. Nutr J. 2011;10:128. Published 2011 Nov 21. https://doi.org/10.1186/1475-2891-10-128
  • 9
    Thaiss CA, Zeevi D, Levy M, et al. Transkingdom control of microbiota diurnal oscillations promotes metabolic homeostasis. Cell. 2014;159(3):514-529. https://doi.org/10.1016/j.cell.2014.09.048

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