If you find it next to impossible to resist the 3 p.m. sugar cravings, that hit you every day and you end up blaming yourself for your lack of self-control, let me tell you, it’s the bugs in your gut that tempt you to eat doughnuts and cakes.
Scientists are at task trying to understand how it is not our “self-control” but the “microbes” residing in our gut (gastrointestinal tract) that controls our appetite and cravings.
Let’s try to understand how do they do this and how we can control them instead of them controlling what we crave for.
Don’t let a sweet tooth or carb cravings limit you from reaching your health goals.
Food choices are a two-way street
Scientists have known for quite some time that what we eat change the balance of microbes in our gut (or gastrointestinal tract) — famously known as the microbiota, based on the types of food we habitually eat.
Choosing to eat junk foods rich in ultra-processed carbs, fats and sugar over healthy food choices (whole fruits and vegetables, whole-grains, fish and healthy fats/protein from meat) is known to increase the populations of specific pathogenic microbes and reduce the numbers of beneficial bugs in the gut.
As this balance in the microbiota population is disturbed, the types and amounts of different substances they secrete are also altered, affecting the activation of different genes and absorption of different nutrients. Therefore, our food choices influence the types of microbes that dominate our gut and hence our health.
“We are what we eat,” but looks like “we are what our microbes eat”.
Turns out, food choices are most likely a two-way street. Gut microbes have been shown to also influence our dietary choices. The gut dominated by certain types of bacteria in flies and mice, for instance, has been confirmed to dictate their behaviour, appetite and food preferences.
The evidence in humans also supports the role of gut microbes (probably by influencing hormones) in controlling food preferences.
Take the case of gastric-bypass, for instance. The microbiota of a patient after a gastric-bypass undergoes a major shift and is followed by a significant change in their food cravings — people with consistently strong urges for sugary foods suddenly stop craving sweets. The scientists now suspect that the success of bypass surgery is due to these changes in cravings caused by the alterations in gut hormones, not the decrease in stomach volume.
If you are wondering what a gastric-bypass is, it is essentially a surgery that helps you lose weight by changing how your stomach and small intestine handle the food you eat. This involves making your stomach smaller so you feel full with less food.
Pregnancy is also infamous for crazy cravings. Pregnant women often find themselves craving for foods completely different from their normal food preferences. The hormonal shifts during pregnancy also affect the composition of the mother’s microbiota. It is possible that different cravings take over as the gut microbes are also affected.
Fecal microbiota transplantation (that involves transfer of microbial consortium from healthy donors) in humans has also shown promise in reducing alcohol cravings.
The evidence strongly suggests that we are simply being played by these gut microbes. They seem to decide what foods we should crave for and control our food aversions.
So, is there a hidden agenda for the microbes behind this? Yes, there is.
They seem to be feeding themselves with their favourite foods to us. We are being used to satisfy their cravings and not ours.
This simply means we need to be smarter in hosting more of those microbes that crave for healthy foods and you will crave the same.
The battle between the microbiota
It is important to understand that there is a wide range of microbes in our gut, and each kind or species of bugs have their own appetite and prefer specific types of foods over others — some prefer carbohydrates and sugars (like yeasts), some dietary fibres (like Bifidobacteria), whilst others prefer fats (like Bacteroidetes).
The microbiome (the microbes, their genes and the products they produce) is all about competition and survival. They compete with each other for their preferred food and space for survival. And they will do whatever it takes to win — even if it involves harming you and putting your health at risk, their very own host.
How do they do this?
The gut and the brain are connected (the Gut-Brain Axis) via the vagus nerve — a collection of nerves that allow communication between the gut and the brain. Bacteria in our gut, for example, use this communication pathway to generate and transport toxins that make us feel crap and promote feelings of low mood. So, we often turn to sugary foods to make us happy, and to satisfy these bully microbes.
Another way our gut microbes may control our food choices is by modifying receptors throughout the gut. For example, the microbes that prefer sugar trigger the body to spike the number of sweet receptors in the gut. As the number of these receptors in the body increase, so does the craving for more sugar.
Bacteria also influence neurotransmitter synthesis. Higher Gamma-aminobutyric acid (GABA) levels correspond to lower sugar cravings and vice-versa. Certain bacteria can produce GABA and if the populations of these bacteria are lower, these translate into increased sugar cravings.
Microbes boost our craving for food that they prefer by altering our taste buds. Sweet foods and those rich in other carbohydrates induce increased opioid and cannabinoid receptors and fire off “happy chemicals” like serotonin and dopamine in the brain. The effects of these chemicals make us more likely to seek them out repeatedly. So they also know how to make us happy and dependent.
A diet high in sugar can create a snowball effect where it blooms the population of sugar-loving microbes, which in turn supports the recruitment of higher numbers of microbes that crave sugar. This leads us to lose our self-control and give in to those sugary-fatty food temptations.
Build a well-balanced, healthier microbiota to fight cravings
Our gut microbiome is constantly changing in response to the foods we eat, certain medications like antibiotics, and our overall health. Therefore, it becomes important to maintain the balance among the microbiota — supporting the growth of beneficial microbes while suppressing those with pathogenic potential.
The key to a healthy microbiome is to increase the variety in your diet from healthy food sources that will in turn increase the variety in your microbiota. Diversity prevents a pathogenic microbe from dominating and pushing hard on your craving buttons.
Probiotic- and prebiotic-rich foods are promising strategies to support a healthy and diverse gut microbiome.
Take control of your cravings before the gut microbes choose the menu for you.
If you would like to know more about how to fix, feed and flourish your gut microbiota, I recommend you to read my article below to help you guide make the right food choices.
Feed, Fix and Flourish Your Microbiota for Healthy Gut and Happy You
A road towards immune fitness with functional diet — prebiotic, probiotic and synbiotic
If you would like to know how sugars can affect your health, you are welcome to read my other article.