On the face of it there is no obvious connection between the microbes in our gut and being able to lose weight. We know these bacteria help us digest food but so what?
We now know that these little critters are important for many functions inside our body, including how our metabolism runs. They’re not just bystanders but active participants inside us.
So what happens if the wrong critters get in there? Could we be condemned to a life of obesity or type 2 diabetes?!
What The Science Says
I’ve reviewed the science on this so that you don’t need to! Here are some of the highlights:
Overweight people have a ‘poorer’ microbiome than lean folk in that it’s less diverse with fewer different species of friendly bacteria. Also, different species seem to dominate than in lean people.
So what? Our microbiome is like a rainforest or a coral reef, a complex and abundant ecosystem made up of thousands of species. The richer and more diverse the number of species, the stronger and more resilient the ecosystem is.
This raises the question: which comes first, being fat or having a crummy microbiome?
Here’s a clue: if you transplant microbes from a fat mouse to thin mouse, the thin mouse gets fat.
This is huge, as it shows that the poor microbiome causes the obesity, not the other way around. Yes, there are many factors involved in getting fat, but it appears our microbiome is in play as a major factor.
But I’m not a mouse!
Sure, but mouse biology is similar to human biology, so we can’t ignore the mouse studies while happily tucking into another round of donuts.
Before long similar studies are likely to be carried out on humans. It’s more tricky as specially-bred sterile lab mice were used, and it’s impossible to create sterile humans. Also it’s harder to control diet precisely with humans than we can do for mice. However it’s only a matter of time.
Bacteria can change the amount of calories that are extracted from the food we eat. This weird fact suggests that bacteria can regulate our metabolism.
We also know that these bacteria effect the insulin our body produces, which has an knock-on impact on how much fat is stored.
The result potentially is that if we have too many of the ‘wrong’ bacteria, we will consistently draw more calories from our food than ‘normal’, making it much harder to lose weight, even if we’re active and watching our diet.
In another recent mouse study: changes to the gut microbiome brought about by obesity lasted for 6 months and predisposed the mice to rapidly regain weight.
This suggests that being obese makes your microbiome poorer (see rainforest example above), and once it gets to this damaged state, it takes a while to get back to healthy, and in the meantime you’re at risk of getting fat again.
This may at least partly explain the dreaded cycle of yo-yo diet failure.
A Path To Obesity
In case you’re still sceptical about the mice, a recent human study found that overweight 7 year-old children had different gut flora when they were infants to those that stayed at a healthy weight.
This means the children’s microbiome went off course when they were infants and from that time onwards they were more likely to be overweight. With more studies we can work out how to prevent that.
It also means it could be several years after your gut flora goes wrong that it leads to you becoming overweight.
Can’t We Just Kill The Bad Bacteria That Make Us Fat?
Unfortunately not, as no single species of bacteria is responsible.
This shouldn’t be a surprise now that we know our microbiome is an ecosystem. Resilience and balance come from having a huge diversity of species. We need to think in terms of rebuilding and nourishing, rather than killing.
As with rainforests and coral reefs, collapse generally doesn’t happen when one species is removed, but rather as a result of cumulative losses, each one gradually eroding the stability of the system.
Once healthy stability is lost, unhelpful species can move in. This is probably why we see different bacterial species dominating in obese people than in lean people.
There is currently a lot of interest around a species called akkermansia muciniphila, the loss of which may be a tipping point that leads to inflammation and obesity. Could it be a ‘keystone species’ that has a disproportionately large effect on our ecosystem, tipping us into obesity if we accidentally kill it?
Weight Loss Made Easier
Don’t panic! Changes to our gut bacteria are reversible. If we start looking after these little critters inside us, soon they’ll be back up and running.
In turn this will help us lose weight more easily.
Sure, it doesn’t get us off the hook for doing all the other necessary stuff to lose weight. We’ll still need to be active instead of sedentary, and we still need to eat fewer calories than we burn each day.
But getting our microbiome in order will give us a tailwind. The other efforts we make will then pay off with faster and more long-lasting results.
For simple steps you can take today, check out my post: Fix your Gut to Fix Your Weight: 6 Dead-Easy Steps and here are my 6 dead-easy steps to switch your gut flora from crummy to magnificent!
6 Dead-Easy Steps
- Eat more unprocessed, homemade food and eat less junk food
- In particular eat less refined carbs like white bread, pasta, pastries, cereal, as the bad bacteria LOVE these
- Take a good quality probiotic for at least 3-6 months
- Have a little live, fermented food or drink (like yoghurt, sauerkraut or kombucha) with every meal
- Don’t go crazy on the antibiotics! Be guided by your doctor, but you don’t need them as much as you think. Save them for real emergencies!
- Lifestyle – make at least one change today out of this list:
- Exercise consistently, light or heavy intensity, both help gut flora!
- Drink less alcohol
- Be less stressed!