Gut Bacteria and Weight Loss Resistance

‘Losing weight’, or as I prefer to call it - ‘losing body fat’, is by far the most popular resolution made every New Year’s day. But it’s also undoubtedly one of the least successful. And, contrary to popular belief, the reason might not be your lack of willpower after all. The real reason might actually be hidden in the health, or otherwise, of the colony of microbes residing in your intestines - your microbiome. So what is the connection between gut bacteria and weight loss?

Well, as anyone who has tried to lose weight/body fat unsuccessfully by eating healthy and exercising regularly will tell you; “there’s something else going on”. And there’s a growing body of science to suggest they are absolutely right. If you don’t have the right balance of bacteria in your gut, it almost doesn’t matter what you do with diet and exercise to lose weight/body fat. It will not budge.

What is weight loss resistance?

Weight loss resistance is a term used to describe the situation where people who, despite an appropriate diet and exercise program, can’t lose their excess body fat. A personal trainer’s worst nightmare. And no, these people aren’t lying about what they eat or how much they exercise. There are other variables that need to be considered.

Most of the reasons for weight loss resistance lead back to either hormone or digestive imbalances. This post is all about the latter; the link between gut bacteria and weight loss resistance.

Wait, tell me more about the microbiome

The human microbiome is basically the trillions of microbes that inhabit the human body. They are estimated to outnumber our human cells by as much as 10 to one and the latest scientific research suggests they have a huge impact on our health. From processing nutrients in the foods we eat and synthesising vitamins, to supporting the immune system and regulating hormones, the bacteria in our gut have an important role to play.

But if this ecosystem gets diminished or imbalanced, the consequences can extend far beyond the intestinal tract. Everything from allergies, diabetes, autoimmune conditions and mental health to, you guessed it, obesity, have been associated with changes in the gut microbiome.


So what is the link between gut bacteria and weight loss resistance?

New research indicates that our gut bacteria (microbiome) affect the way we store fat, how we balance blood glucose levels, and the hormones that make us feel hungry or full. The wrong mix of gut bacteria can even set the stage for obesity from the moment you are born. So, what are some of the latest studies and what can they tell us about our microbiome and our weight?

Show me the science - bacteria and body fat

The Fat Microbes > In 2006, scientists first discovered that an imbalance in the microbiome could lead to obesity in animals. Researchers from Washington University found that obese mice had higher amounts of a gut microbe called firmicutes. Which, it turns out, are too efficient at extracting energy from food, breaking down food and increasing the absorption of fat. This was the first insight into the possible connection between gut bacteria and weight loss.

Transplanting Obesity > A 2013 study used faecal transplants from humans to mice in a gross and fascinating experiment. What they found was that healthy mice could be made obese by transferring faecal matter, and the microbes that go with it, from obese humans to the mice. They also found that transferring faecal matter from lean humans to the mice prevented the mice from putting on weight.

Not Responding to a Healthy Diet > The microbiome you have determines how you absorb and process nutrition according to a study in 2016. Researchers found that a gut shaped by an unhealthy daily diet won’t respond as quickly to a healthy diet as a gut shaped by vegetables and fruits that has more varied microbes to begin with. This makes it tricky for anyone starting a health kick after years of an unhealthy diet. You may have to be more patient with results as your microbiome adapts and changes with your new lifestyle.

Yo-Yo Weight Gain > Another 2016 study recently suggested that yo-yo type weight gain could be the result of specific strains of gut microbes. The researchers found an intestinal microbiome signature that persists after successful dieting of obese mice, which contributes to faster weight regain upon re-exposure to a less healthy lifestyle. The changes to the gut microbiome brought about by obesity were observed to last five times longer than the actual time spent dieting. Not good news for those trying a short-term diet after years of being overweight.

SIBO Obesogens > Obesogens are basically anything that disrupt lipid metabolism and yes, make you obese. Or at least, gain weight. One such obesogen, a type of archaea known as M. smithii, is responsible for constipation dominant Small Intestinal Bacterial Overgrowth (SIBO). And a study in 2013 found that the amount of M. smithii is predictive of weight gain in mice. Commonly found in sub-saharan African populations, M. smithii is associated with higher calorie extraction from food. Great if you are starving, not so great if you eat healthy, or otherwise, three to five times a day.

Antibiotics and Weight Gain > We all know that antibiotics generally aren’t good for your gut. And a study in 2014 showed that when young mice were given low doses of antibiotics, they develop about 15 percent more body fat than mice not given antibiotics. This is particularly worrying, given the overprescription of antibiotics in children we are currently seeing.


Ok, so I get the connection between gut bacteria and weight loss resistance. What can I do about it?

Now that we know there’s more to the weight loss story beyond a healthy diet and good exercise program for many people, what should we do? Well, if there’s one thing we know, it’s that everyone’s microbiome is as unique as their fingerprint - no two people are the same.

It really depends on your health history and lifestyle from birth, as well as what exactly is going on inside your gut. The approach you take will depend on whether you have:
> Not enough good bacteria
> Too many of specific types of bacteria
> Particularly nasty types of bacteria, archaea, parasites or yeast/fungus.

But, as with a lot of things, there are a few basic gut health tips you can use to get started in the right direction. These include:

Focus on diversity

Eat real food, mostly plants and as diverse as possible. It is this diversity that researchers recommend as being crucial to a healthy microbiome. Eat the rainbow, as they say. Fibre-rich fruits and vegetables are what help stimulate the growth of good bacterial species. The average person is estimated to only eat around 20 different foods per week, which is way too low considering our ancestors are thought to have had as many as 150. So get out of your standard routine and look to mix things up by adding a few new ingredients each week.

Food sensitivities and intolerances

Reducing inflammatory foods is critical to healing your gut microbiome. These include foods you are sensitive or intolerant to as well as some processed foods, alcohol and sugar. If you have not had a food sensitivity test or done an elimination diet, you can start with eliminating some of the most common culprits; gluten, dairy, eggs, soy and nuts. After two to four weeks, bring them back in one at a time and see how you feel.


Foods Rich in Prebiotics

Prebiotic foods can stimulate the growth of good bacteria. This list is a little obscure, however try to get some raw: chicory root, Jerusalem artichoke, dandelion greens, garlic, leek or onion into your diet on a daily basis.

Fermented (Probiotic) Foods

Foods like yogurt, sauerkraut, kefir, kombucha, miso, microalgae such as spirulina and chlorella, tempeh and kimchi are a few of my favourites. You can also supplement with a good quality, practitioner recommended, probiotic with at least 10-30 strains and 15-100 billion units.

Forget Antibiotics as First Line

Before you start trying to repopulate and diversify your microbiome, you need to make sure you’re not constantly killing it off with round after round of antibiotics. Not only do they kill off all of the pathogenic flora but they will also kill off everything else in their path, especially the good guys. Urinary Tract Infections are a great example of where it’s possible to heal yourself using natural products that won’t ruin your gut.

Find the Root Cause

There’s a limit to what basic gut healing dietary strategies can achieve if you have an undiagnosed gut dysfunction. If you’re struggling with weight loss resistance and also experience any digestive discomfort, then finding and healing your root cause is key to any lasting improvement.

I generally find that those suffering from weight loss resistance have one or more of the five most common causes of IBS. Once we identify and treat the root cause, then a healthy diet and appropriate exercise program is generally all they need to lose the excess weight that they have been struggling with.

So, if you’re embarking on a new year’s resolution to lose weight but are worried that gut dysfunction could derail your plans, get in touch and let’s sort you out. Healing the gut is a journey. If you are ready to begin yours, please head to the Work With Us page to learn more about how we work online with clients in many countries to test for and treat the various root causes of IBS symptoms and other GI conditions.