It’s quite possible you don’t think about it very often, but I expect you know that whenever you eat, you’re not really feeding yourself so much as you’re feeding around a hundred trillion microscopic microbes that live in your intestines. Of course it’s natural to be somewhat put off by this very strange arrangement, but these microbes are being seriously and extensively studied, and it looks like they’re considerably more significant than you may realise.
Quite apart from the massive impact they have on your health – with regard to autoimmune disease, metabolic syndrome, and even your life – there’s increasing evidence that these gut bugs are a major factor in your ability to gain or lose weight.
First, consider that American farmers have known for decades that animals fatten up faster when given antibiotics – which disrupt the gut microbes. 80% of all antibiotics sold in the US go to their livestock, so that’s a lot of fattening up.
In research, specially bred microbe-free mice simply don’t gain weight, no matter what and how much they are fed. But when these mice had gut bugs introduced their body fat more than doubled, even though they ate the same. If the gut bugs introduced came from obese mice, the weight gain was considerably larger.
As for us humans, many studies have found that the gut bugs in overweight individuals are clearly quite different from those in lean individuals. There’s a striking lack of diversity, with large increases in some strains and others in decline. The question is, does being overweight change that balance of gut bugs, or does a change in the amounts and diversity cause weight gain? It could be a bit of both, but from that mouse research and many other human studies, it looks like the latter is by far the most significant factor.
So… look after your gut bugs and they will look after you.
Tens of thousands of different stains of gut bugs have been identified so far. Each person carries trillions, mostly in the colon, and weighing in total as much as 5lbs. But each one of us is likely to have only around 1,000 different kinds or even less, so there’s potentially a huge variation from person to person.
If you’d asked me before I started writing this article what gut bugs eat, I’d have said “fiber” – but it turns out that we have an impact on them no matter what we consume. Just like the players in an action movie, gut bugs can either be good guys or bad guys. Whatever we eat, we either support the good or the bad.
Without the good guys, we wouldn’t last very long. Feed them and you get essential, anti-inflammatory, short-chain fatty acids, a greater sensitivity to insulin, B vitamins, vitamin K and very helpful gut hormones that control your appetite.
Feed the bad guys and you get systemic inflammation. The bad guys leave residues called endotoxins, which get into your blood stream, causing inflammation in every cell in your body. Your body is entirely capable of dealing with that if it happened once in a while; the inflammation response is the coping mechanism itself. However, when this response is constantly activated, day in, day out, for decades… you get metabolic syndrome, autoimmune disease and excess body fat that’s tough to shift.