Can a healthier gut help you lose weight?

Gut health and weight loss: What’s the connection?

When people reach out to me for help in increasing performance and weight loss most of the time they want to know how many grams of protein to eat and when to eat each macronutrient for better recovery. While these things to do matter for sports performance and body composition, there is one really important element to body composition that is often overlooked: gut microbiome.

There are several trillion microbes in the human body that reside in the gastrointestinal tract. Their gene codes can impact our physiology in various different ways. While weight loss is only one small part of what these powerful microbes can do, I’m going to be covering this very topic in this week’s blog.

What is gut bacteria and why is it important?

You’ve probably heard that bacteria can be good and bad. Our guts are home to a lot of bacteria, the good ones and the bad ones. When they’re good, they’re really helpful, but when they’re bad, they can cause a whole list of ailments.

Our gut microbiome profile is influenced by several factors but not limited to age, gender, diet, level of daily activities, stress and medication.

Fun fact, how a baby is born (vaginally or via cesarean section) can also affect how gut bacteria is colonised! Not surprisingly, however, breastfed babies are given a better chance of having healthy guts due to the nature of momma’s milk that comes with immunological assets, setting the baby up for a stronger immune system.

Having a healthy gut means that your body is more ready to absorb some important vitamins nd minerals such as B12, K, B6, B5, B3, folate and biotin. This is especially important because a shortage of some of these vitamins can tank your immune system leaving you susceptible to illnesses.

How can gut microbiome affect your body weight?

Our gut microbiome affects how we digest food.

When we eat certain foods, they get digested into the digestive tract and depending on the quality or type of food you eat, they then get fermented and turn into short-chain fatty acids that eventually bind to receptors (a membrane structure that allows a cell to recognise substances and receive messages) in your gut cell wall and produce a bunch of hormones.

Some of those hormones affect how our bodies digest food and signal satiety. Glucagon-like peptide (GLP-1) for example can enhance insulin release and slow gastric emptying. When you eat carbohydrates, your small intestines tell your pancreas to respond by releasing insulin.

You may have heard fitness inspos refer to insulin a lot when discussing weight gain, this is because insulin is released by the pancreas as a way to control your blood sugar. So having a healthy response to insulin means that you are able to lower your sugar levels back to normal after consuming a meal high in carbohydrates.

Geeky side note: Pharmceutical companies now sell analgogues of GLP-1 to help patients living with diabetes.

Another hormone that directly suppresses appetite and slows down digestion as it prepares for the movement of food through the large intestine is Peptide YY. A diet high in protein causes the release of PYY the most, which of course means that eating a lot of protein can help you to manage hunger and stay full for longer.

Various studies in humans and rats have shown that a change in the diversity of gut microbiome can significantly result in improved BMI, weight and fat mass.

In one case, a woman who had a fecal transplant became obese, gaining over 40lb rapidly after receiving the transplant  from an obese donor. 

At this point you might be wondering why anyone would need a poop transplant, but this has been an effective medical procedure for patients with Crohn’s disease and other devasting bacterial infections.

In short, having a healthy gut “executes essential functions that the body itself is incapable of performing. It promotes gut maturation, educates the immune system, provides protection against viral and bacterial pathogens, influences brain activities and bodily metabolism.” (Mills et al, 2019)

But an important side note here, an unhealthy gut can also be the cause of low body weight since a leaky gut can make it difficult for important nutrients to get absorbed.

Enough with all the geeky science, let’s get to what actually causes an imbalance to our gut microbiomes and what you can do about it.

What causes an imbalance in our gut microbiome?

There are several factors that influence gut microbiome composition and it’s important to recognise that although a part of it might be down to genetics and other things outside our control, there are other contributors to how they are developed that are within our control and that is down to our lifestyle including how we move and how we eat.

Stress

Let’s start with the greatest threat to our gut microbiome that might not be all that obvious. There is a relatiohsip between our gut and our brains, and it’s no coincidence that when we have a feeling about something not right, it’s called a “gut feeling”.

When we experience stress, our digestive system slows down. You may have noticed that you aren’t able to eat or don’t have much of an appetiete when you’re nervous of worried about something. That’s the cross-talk bewteen the brain and gut happening.

Here is another interesting connection between our gut and brain. You have probably heard of serotonin as the happy hormone. Well 90% of serotonin is used in the digestive system. So you see, the two are quite tightly intertwined. In fact, psychological stress in rodents have been shown to reduce Lactobacillus (a type of probiotic).

When we are well rested and happy, our gut can receive up to half of all organ blood flow, but during times of stress (whcih by the way also includes intense bouts of exercise), blood flow to our gut can decrease by up to 20% which can increase gut wall permeability (leaky gut), making it easier for things to come in and out of the gut.

With a leaky gut, its kind of like having half drunk bouncers letting agressive people in and shoving nice people out of a bar for no good reason.

This can obviously cause many disruptions in our bodies.

Next, let’s look at the nutrition aspect. Eating the right stuff can dramatically enhance your gut health and increase the biodiversity of your gut microbiome and I’ll be discussing that in the next section but right now let’s talk about some of the common trigger foods.

What you eat and what you don’t eat

As a regular visitor of my blogs and social media platforms you probably see me talk extensively about being able to enjoy some processed foods for the mindset. Often by saying this people misunderstand it to mean I encourage lots of processed foods. This is just not the case at all. 

In my experience as a sports performance nutrition coach, I have found too many athletes unnecessarily restrict their diets because they fear having any form of processed foods will impede their progress. Allowing yourself to enjoy the occasional treat is absolutely harmless if not beneficial to your long term progress, but it should be enjoyed as part of a balanced diet, rather than make up the majority of your diet.

So what are some of the things that can trigger gut issues

Your lifestyle choices can affect your gut health.

Contributors to poor gut health are:

• Longterm use of NSAIDs (anti-inflammatory drugs)

• Excesive amounts of refined sugars and other processed foods

• Bacterial infection

• Candida

• Excessive alcohol consumption

• Excessive consumption of sugar alcohols (present in many sugar free “health food” products)

Note I have used the words “excessive” to highlight exactly that. Ultimately it’s more about the ratio of said habit rather than the habit itself. 

What can you do to restore your gut health?

Exercise

Physical movement changes how our gastrointestinal tract by determining how food moves along its system, thereby affecting the movement of nutrients across cell walls, and as a result can change the metabolic profile of your liver, fat cells an muscles. 

Increase fibre intake

Let’s face there are many reasons why you should be eating vegetables but in this case, we aren’t just referring to vegetables. Fruit, nuts and wholegrains also fall into this category. Our bodies don’t actually digest fibre but the bacteria in our bodies munch on it a little, so think of it as keeping the little guys in your gut happy. If they’re happy, you’re happy.

Increase your Omega-3’s

The anti-inflammatory nature of these foods such as hemp, flax, oily fish, algae can all help your gut health. Coconut oils a form of medium chain fats have also been shown to improve gut health.

Eat fermented foods 

While scientists are still working on building a stronger case for the benefits of fermented food on the digestive health (since most of it is more related to cardiometabolic health) there is certainly no harm in enjoying your fair share of delicious fermented foods.

Note: Research suggests that fermented dairy products such as kefir are the only fermented foods sources that contain probiotics, although the benefits are mostly related to cardiometabolic health.

Here are some of my favourites:

Kimchi 

Yoghurt

Sauerkraut

Kefir

The best part is that you can make your own kimchi too. Here is my go to recipe for kimchi.

Do I need to take probiotic?

It depends. To save you hours of research I’ll keep this simple; just like there is no ‘one perfect diet’, there is also no clear definiton of what the perfect ‘gut profile” is. This is because most of the studies have been done on animals, not to mention there is no standardisation on probiotic strain (there are literally hundreds), length of trials, and dosage.

However, this isn’t to say that no one should take probiotic supplements. Because each person responds differently to supplements under different circumstances, an individual on antibiotics for example may find it beneficial to take probiotics.

The good news however is that most of us don’t need supplements to help us increase the microbe diversity in our gut. Studies show that in just 1-3 days of significant changes to the diet, noticeable changes to the microbiome composition can be detected.

To wrap up…

Our gastrointestinal tract is comprised of both good and bad bateria. Making sure that we have enough good bacteria can ensure that we absorb the right nutrients, manage satiety and maintain a healthy body composition.

Your gut health is more than just about what’s happening in your gut, it’s connected to your brain and various other systems in your body. An unhealthy gut left unchecked can cause all sorts of uncomfortable symptoms.

Lifestyle choices can dramatically affect the ecosystem in your gut. A mix of movement and a balanced diet can attenuate the effects of leaky gut or in some cases prevent it all together.

Resources:

Mills, S., Lane, J. A., Smith, G. J., Grimaldi, K. A., Ross, R. P., & Stanton, C. (2019). Precision Nutrition and the Microbiome Part II: Potential Opportunities and Pathways to Commercialisation. Nutrients, 11(7). https://doi.org/10.3390/nu11071468

John GK, Wang L, Nanavati J, Twose C, Singh R, Mullin G. Dietary Alteration of the Gut Microbiome and Its Impact on Weight and Fat Mass: A Systematic Review and Meta-Analysis. Genes (Basel). 2018 Mar 16;9(3):167. doi: 10.3390/genes9030167. PMID: 29547587; PMCID: PMC5867888.

Sonnenburg JL, Bäckhed F. Diet-microbiota interactions as moderators of human metabolism. Nature. 2016 Jul 7;535(7610):56-64. doi: 10.1038/nature18846. PMID: 27383980; PMCID: PMC5991619

David LA, Maurice CF, Carmody RN, Gootenberg DB, Button JE, Wolfe BE, Ling AV, Devlin AS, Varma Y, Fischbach MA, Biddinger SB, Dutton RJ, Turnbaugh PJ. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 2014 Jan 23;505(7484):559-63. doi: 10.1038/nature12820. Epub 2013 Dec 11. PMID: 24336217; PMCID: PMC3957428.