man food shopping

Many of us looked forward to that Thanksgiving meal and those December holiday cravings are starting to kick in. I, for one, found myself wondering why we have cravings for certain comfort foods. So I took a peek into the possible reasons for our cravings and the leading one may surprise you.

Firstly, we need to understand how our gut works. After the mechanical manipulation of chewing, food lands in the gut for a nice acid bath and digestion. Monitoring the whole thing is the ENS, enteric nervous system, which is an extensive network of neurons regulating: fluid exchange, blood flow, gut movement , physical condition and information about the gastrointestinal tract. The ENS in turn communicates to our brain via the vagus nerve through the secretion of hormones like peptide YY and cholecystokinin to tell us when we are full.

Now it’s time to get to the issue of cravings. For a long time people believed that our bodies would get cravings for foods that we needed. But new research is finding that the microbial life forms that live in our gut might be influencing our eating habits to best suit them. This sounds iffy at best but when you consider that in our bodies bacteria cells outnumber our own 10 to 1 it seems reasonable to say they are having an effect on us.

So when I dig into my Thanksgiving Day baked yams I’m not only feeding me, but also all the bacteria inside me. Keeping the bacteria happy and healthy is just as important to good bodily function as keeping me healthy and happy. But, can my bacteria be influencing my habits?


Because bacteria treat our bodies like an environment, they have developed ways to influence that environment to be best suited to them. To this effect there are numerous proposed microbial methods of altering our eating habits in an effort to better their environment. These include: influencing the reward and satiety pathways, production of toxins that can alter our mood, changes to receptors like taste and the hijacking of the vagus nerve. It is also proposed that our own antibody response to bacterial peptides that mimic human hormones or the peptides themselves might be causing interference.

Despite uncertainty in the how, it is generally accepted that microbes are having some effect on the cravings we experience. In fact affecting gut bacteria composition is the idea behind the use of prebiotics, probiotics and dietary changes. Altering microbiota may, in the future, be an approach to dealing with problems like obesity and unhealthy eating. Giving a whole new meaning to the concept: you are what you eat.

 prebiotics as yogurt
In the end, we all have cravings and they sometimes get us into trouble; so here are three healthy tips on how to deal with cravings when they occur:

  • Craving something sweet? Avoid refined sugars; if you feel a sweet tooth craving coming on, opt for some fresh fruit instead. The naturally occurring sugar will satisfy.
  • Craving a snack? Check your mental state: if you feel cravings coming on sometimes it can be a way to cope, or a force of habit. Instead of snacking, try to indulge in a hobby to relax yourself, go for a brisk walk, or enjoy a small bit of natural nuts and dried fruit.
  • Craving a pick-me-up? Try to stay well rested. Do not grab an energy drink, grab an apple instead for a little natural kick to keep you going.

If you’re interested in more food for thought this holiday season, checkout the PubMed scientific article by Alcock J, Maley CC, Aktipis CA for more background on how bacteria might be affecting us.

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