There’s nothing wrong with eating a second helping…
Unless, of course, you’re already full. And you’re not really sure why you’re eating the second helping. And when you’ve finished, you feel bloated and immobile and sleepy. And you fall asleep shortly after finishing, forcing your body to digest your meal in your sleep, which forces your digestive system to work twice as hard and impedes the quality of sleep you’re getting.
In the ever-evolving field of gut health research, scientists are asking the question: Is overeating less of a personal choice and more of a chemical response in the body?
In other words, can eating for pleasure, instead of eating to stave hunger, actually be traced to bacteria in the gut’s microbiome?
The short answer? Yes.
Let’s break down how eating behaviors are trained in the brain, so that we can understand why a metabolite in the gut might even be able to affect change.
The answer actually has to do with the brain’s pleasure systems.
Food as a Reward
There are two particular areas of the brain contributing to overeating – the nucleus accumbens and the amygdala.
The first has a command in motivation, reward, pleasure, positive and negative reinforcement, and distaste. The second plays an important role in the regulation and experience of emotion.
You can see why those two areas would affect and be affected by addiction in general, and in this case overeating – it’s not a survival impulse. It’s an emotional impulse.
In studies done on food as pleasure stimuli, those two centers of the brain are lit up prominently when subjects were hungry or eating, especially in those subjects with overeating tendencies. In fact, you can actually predict how likely someone is to treat food as a reward based on the strength of the brain function in those regions.
Here’s what we know about habits: they’re neurological. Behavior reinforces itself by retreading the same neural pathways until the brain forgets it can travel a different way.
The more hedonically a person eats, the more that behavior becomes built into the brain’s blueprint.
But now we also know that the gut and its microbiome can have a hefty influence on how the brain behaves and what it gets told to do…
Like in the case of a certain metabolite called “indole.”
The Tryptophan Metabolite
Metabolites are small molecules that are formed as a result and at the end of metabolism. This means they are directly affected by what and how often we are metabolising.
Recently, scientists have found that the metabolite indole, which is produced as a result of metabolising tryptophan, has a connection with overeating.
Tryptophan sound familiar?
It should… it’s the essential amino acid that always gets the blame for inducing food-comas from too much turkey at Thanksgiving. Tryptophan serves lots of purposes…
It can balance nitrogen in adults, producing niacin with the help of several other vitamins (which in turn produces serotonin), and promoting growth in babies.
And it’s not just found in turkey. Tryptophan is found in chicken, cheese, fish, peanuts, pumpkin and sesame seeds, chocolate, milk, eggs, and more.
Now, it isn’t necessarily a bad thing.
When the gut’s bacteria break down tryptophan, the aforementioned happens. But what we’ve also learned is that people who have higher levels of indole as part of their regular bacterial balance in the digestive tract also have strengthened function of those two brain areas, the nucleus accumbens and the amygdala, when hungry or eating.
The suggestion is that there may be a chemical reason for overeating. It doesn’t develop in everyone, after all. All of the answers haven’t been found – it may be that certain microbiomes are able to produce indole from tryptophan better, or that certain bodies are more susceptible to the effects of the metabolite indole.
But as research progresses further…
Pay attention to your own eating habits. Are you eating past the point of fullness? Are you snacking all day? Are your meal portions bigger than you need?
Take a proactive role in rewiring the neural pathways in your brain not to thrill in the reward of excess eating…
And instead, chew. About thirty times more per bite than you’re probably chewing now. Savor. Sip. And always…
Listen to your body.