The tiny little bugs that may be widening your waistline

What if we could eat our favourite foods without absorbing all of their calories? Well this isn’t wonderland talk. It can be a reality with the help of the trillions of little bacteria, named microbes, that live in your digestive system.

For decades we knew of this community of bugs living in our intestines and didn’t pay them much attention, thinking they simply aided in the process of digestion. As an ever increasing amount of research stacks up, we now know that the impact of microbes us way more significant than had been though. These microbes are affecting our general health, immunity, mental health and body weight – given that they are so tiny, they certainly carry a lot of punch!

We are actually host to tens of thousands of different species that add up to over 1kg and collectively have 100x as many genes as we do! That means that over 90% of the genes in our bodies are microbial not human!

In our gut community there are beneficial “good” microbes and there are pathogenic “bad” microbes. Recent studies are now drawing links between an excess of the bad guys to several health conditions such as obesity, diabetes, autoimmunity, cancer, autism, allergies, heart disease, asthma, eczema and psoriasis.


Your microbes send chemical messages to your brain that control both appetite and mood. So the bugs in your stomach can be the cause of those uncontrollable sweet cravings.

It is believed that gut microbes play a key role in processing foods and deciding exactly how many of the calories and nutrients that the body will absorb. Some microbes can even influence your sensitivity to insulin. Insulin is the hormone that removes sugar from your blood helping you to burn fat that otherwise would have gone straight to the belly.

So how can these little bugs control your appetite? Well let’s take a look at the microbe species Helicobacter pylori (H. pylori). For example these bacteria lower your stomach’s production of ghrelin, the “hunger hormone”. When we wake up and the belly starts to rumble, this is ghrelin saying “hello”. Then, after we eat breakfast ghrelin levels decrease. However, if we don’t have enough H.Pylori bacteria present, it won’t. This means you’ll still be hungry and want to eat more.

Although research is strongly suggesting that a healthy gut ecosystem is a significant factor in weight gain, don’t go getting all blame-y and pointing your finger at them (whist ignoring your XL pizza & diet coke last night!) – it’s nowhere near that simple. Our microbes cannot solely be to blame for our health problems as lifestyle (diet, stress, sleep etc.) is the biggest determinant of a thriving and diverse a gut ecosystem.

So it seems that for effective weight loss it may be less important to monitor how many carbohydrates, protein and fat to eat and more important to monitor your balance of gut bacteria.

Microbial Diversity

We now know that those with a less diverse population of microbe species are far more likely to suffer from inflammation, weight gain, and obesity and will likely have many of the risk factors for the development of other serious health concerns associated with being overweight, including diabetes, heart disease and cancer.

A 2013 study looking in to exactly this found that lean people have up to 70% more gut bacteria and a far more diverse microbe community than that of their overweight peers.

Another more recent study was conducted looking into the gut of almost 300 Danish people. Of that 300 about 170 were obese and about 130 were lean. The 130 lean subjects had much higher microbial diversity than did the obese subjects. This means that they had far more species of bacteria inhabiting their gut than those who are obese. Of the 170 obese subjects, those with the least bacterial diversity (least species of bacteria inhabitants) were far more likely to continue gaining weight over the 9 years the that study took place. Also, those subjects with the least microbial diversity (regardless of their weight) were more likely to develop risk factors for type 2 diabetes, cancer & heart disease!

This suggests that those with poor bacterial diversity are more likely to develop risk factors (such as insulin resistance and inflammation) than are those with a diverse gut microbe population – regardless of their weight.

The good news

Just like a garden, we are able to regrow a healthy gut environment.

Our genetics influences our microbes, but your diet & lifestyle have a huge influence too, and that IS in your hands .What you eat directly affects your gut bacteria, for better and for worse. So the food that you eat can either change your gut bacteria promoting weight gain, or change it to support weight loss.

So how exactly do you get started regrowing a healthy gut community? Well, a great place to start is with cutting out sugar. Sugar is your “bad” microbes absolute favourite source of fuel.

For more about how to get a healthy gut and a slimmer waistline check out my Good Gut Guide program.