Microbiome

How Gut Bacteria Control Your Cravings

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Samuel Anthony
Sep 11, 2022
Bacteria in the microbiome next to junk food including pizza and chips

How Bacteria Control Your Cravings

It's not you. It's bugs.

Cravings can be a real problem, and many people struggle to change their lifestyle due to those powerful desires for unhelpful foods.

But, forget self-control; what if those cravings were not coming from you?

What if they were coming from other living beings inside you?

Some estimates suggest that 100 trillion bacteria and fungi live in your digestive system and collectively form what's known as The Gut Microbiome.

In other words, up to 90% of your cells are bacteria.

Studies have shown that the microbiome can influence body fat and weight loss, sleep quality, immune health, mood and mental health disorders, and even how we eat and digest food.

But what if gut bacteria could influence our cravings and keep us latched to specific foods they want?

They can do so via a long nerve connecting the gut and mind (the gut-brain axis) and can keep you locked into those bad habits.

Alternatively, they can keep you on track and craving the right foods when you know how to nurture them.

A burger surrounded by vegan junk food

Bacteria produce peptides.

Peptides are proteins that can regulate cravings and hunger.

Increases or decreases in these peptides can change how often we think about food and how long it takes us to feel full while eating.

A study on mice showed that there was even a relationship between taste buds and gut bacteria, with mice living in bacteria-free environments developing a much sweeter tooth.

A macaque eating fruit during daytime

Why do bacteria influence our cravings?

Like every being on this planet, bacteria have a desire to stay alive or, better, thrive by eating food!

By altering your cravings, gut bacteria can ensure you choose to consume the foods they need to survive.

Now here is where it gets interesting.

The species most dominant in your gut microbiome can change over time; therefore, what your gut bacteria need to survive can change over time.

The food you eat significantly determines which species are present and thriving at any time.

For example, if you eat a lot of fibre, you will feed fibre-loving bacteria in your gut but perhaps not offer much for other species.

If you eat a lot of fat and sugary foods, the composition of bacteria will change to something that can survive with those compounds. At the same time, the fibre-loving species may begin to diminish.

So, bacteria influence your cravings to keep you latched to what helps the most dominant species survive.

Bacteria illustrations

It makes sense for these bugs to influence your eating habits.

For example, let's go back to those bacteria that thrive in fat and sugar fuelled humans.

If that human changes their diet to reduce fat and increase fibre, the present bacteria will not be accustomed to this new diet.

They were species that relied on the person's old food sources to survive.

So now they want to do anything to protect their survival and dominance in the gut.

One of the best ways to do this is to influence how we feel about food by using happy chemicals and neurotransmitters (which they can produce) to make us feel rewarded by the foods they choose.

Without the foods that particular species needs, it will begin to depopulate, and another species (e.g. fibre-loving bacteria) will increase its influence and domination.

The extent that they can influence our thoughts and decisions is still unknown, but the pathway for influence over our cravings exists and benefits their species' survival.

white and blue thermometer at 37

But aren't bacteria harmful?

While it is not as simple as bacteria A are good, and bacteria B are harmful, there is an understanding that certain species are more dangerous than others.

In total contrast, some species can be incredibly beneficial to us.

"Good" bacteria (to keep things simple) can help us digest food, unlock more nutrients from previously wasted plant fibre, defend our gut wall, and protect against infection.

When they take the lead, your cravings will reflect this.

People who eat fibre are likely to have fibre-loving bacteria.

Without the presence of a food source fit for their species, certain bacteria will die or flee.

If your diet is poor, then it could be some of the more harmful species you're managing to harbour, and in doing so, you could be reducing the populations of "good" bacteria.

Why does this matter?

For self-interest, over millions of years of co-existence, they have learned how to master our minds and, in doing so, can make you crave and thus consume the foods they rely on to thrive.

They can use chemical messengers and happy hormones to reward behaviours when you consume certain foods.

So yes, if you eat a poor diet and feed or consume harmful bacteria, things could be problematic.

However, a broad and balanced plant-based diet rich in fibre should encourage a flourishing, diverse and rewarding microbiome.

A bowl full of fibre-rich plant-based food, vegetables and greens

Escaping the cravings: the complex solution

Don't worry; I don't mean complex as in difficult.

I mean complex carbohydrates!

Complex carbohydrates, like fibre, take longer to break down than simple carbohydrates, like sugar.

All carbs are essentially strings or chains of sugars bound together.

Smaller chains or independent molecules are simple carbohydrates closer to sugar and easy to break down quickly.

Our gut breaks down these simple carbs fast.

Fast absorption can mean blood glucose spikes, and we will likely have absorbed the majority by the time your food reaches the microbiome in the large bowel.

Complex carbohydrates take so long to break down compared with simple sugars that some carbs, like fibre, cannot be digested without the correct gut bacteria.

The slower digestion and absorption means more food reaches our gut bacteria, and that glucose release is much more gradual.

Gradual glucose release means longer-lasting energy and a far less likely blood glucose spike or slump.

On the left, sugar. On the right, vegetables.

By feeding those beneficial microbes fibre, we will begin to change the relationship between gut and mind.

Your cravings for those unhelpful foods will lessen, and your ability to digest new fibre-loaded foods will also improve as new fibre-loving bacteria will begin to grow in number and help you over time.

The best solution to confront those cravings will be different for all of you, but a slow and gradual increase in natural, unprocessed whole food plant-based food sources could help increase the 'good' bugs and reduce those cravings.

Sources & References

Plant-Based Nutritionist & Fitness Coach
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