Mysteries are a staple in the entertainment business. Something nefarious has happened and it’s up to the hero to go through the clues and find the responsible suspect. Usually, when the answer is discovered, all the pieces are put together and eventually, the revelation is made…

(Usually with an all-knowing smirk…)

Mysteries are also a major part of scientific research. Large, scoping questions are asked and over years, clues are revealed through the tireless work of labs all over the world. It may take decades but eventually, the answer is found and the results are shared with the world.

Of course, there are times when the answer seems to be impossible to find. Researchers are left scouring through the data in the hopes of finding something that may open up a path to discovery. But more times than not, the results offer little direction allowing hope to be replaced with…


I’ve been there numerous times and one of the things I find is that when I get stressed, I tend to get hungry. Making the situation worse is that the pangs are not satiated by eating healthy food. I want something bad, fatty and sugary. It could be fish and chips, a fatty burger, or…

(A tart…)

This phenomenon, known as stress-eating, is quite common although how it happens has been, in itself, a mystery. For decades, researchers have been working with people and animal models in the hopes of finding the one mechanism – or if they are lucky the one cell type – responsible for this rather poor health choice.

Now, we may finally have an…

(Aha! moment…)

It comes in the form of a paper entitled, Microglial Inflammatory Signaling Orchestrates the Hypothalamic Immune Response to Dietary Excess and Mediates Obesity Susceptibility. You can click on the title to read the paper.

The researchers used mice to explore what happens inside the brain during what is known as diet-induced obesity. It is a well-known condition caused by a very familiar villain of health. I’m sure you’ll know it as soon as its name is revealed…

(Sorry, Moriarty…)

It’s inflammation.

When the body suffers from this ailment, immune cells drive other bodily systems to alter their function. This happens in the gut, in the blood, and yes, even in the brain. In the latter, the immune cells involved are known as…


They are the soldiers responsible for ensuring the brain is protected from infections, injury, and other invasions. These cells had been shown to be involved in increasing one’s appetite for unhealthy foods particularly when the body experiences stress.

But no one could quite figure out how or why…

The team focused on the area of the brain known to be responsible for the need to eat. It’s officially called the mediobasal hypothalamus, but is more commonly referred to as the MBH. To give you an idea of the size of this region…

(Here’s the hypothalamus…)


(And here is the MBH…)

The first experiments examined the concept of a loss of function. In other words, they reduced the cell’s population from this area and also prevented these cells from doing their jobs properly. As expected, both helped to reduce the urge to eat in the animals.

The next stage of the process required them to do the opposite and amp up the effects of the microglia. To do this, they created a hyper-inflammatory environment. When they did this, the mice had severe hunger issues.

These experiments were run of the mill neuroscience and little can be concluded from this information. But before you start wondering…

(When will he get to the good stuff?)

Let me tell you that we’re close to that Aha! moment.

When the microglia were hyperstimulated, something else happened. The mice became resistant to a particular chemical known to be involved in obesity and other weight-related issues. It’s called…


I know it doesn’t look like much but this little protein has a huge impact on our ability to control our weight. It helps to control how happy we are with the nutrients inside us.

But if we lose out on the ability to respond to leptin, a condition called resistance, a rather vicious cycle occurs. We tend to eat more sugary and fatty foods in order to feel full. But since we can’t sense that fullness, we continue to eat. Put it this way…

(Leptin resistance is bad…)

In this experiment, the researchers had caused leptin resistance by making the microglia hyperactive. In turn, this led to the initiation of the cycle, and the mice became obese.

Now you can say Aha! or perhaps even…


So, to recap:

  1. Stress changes the way microglia function in the brain including the MBH;
  2. They can get overexcited and become resistant to leptin;
  3. Leptin resistance can lead to changes in energy balance & reduce the sense of fullness;
  4. This leads to an urge to eat sugary foods;
  5. This in turn eventually can lead to weight gain.

The overall results of this study do help us to solve the mystery of stress-eating (at least in mice). But the information also introduces another more intriguing question…

(Can we prevent obesity?)

Although we won’t know this for quite some time, the clock may already be ticking in this direction. When the researchers took out the microglia, they used a drug called PLX5622. It’s being tested in clinical trials to manage arthritis. With these results in hand, the drug may be given further examination to see whether it may be able to help calm down the microglia and possibly control stress eating.

But that is for the future. In the meantime, when we feel stressed and find ourselves stricken with the munchies, just realize we may not to blame. Based on this study, it may be just our microglia forcing us to think and act this way. With more research, we may be able one day to find ways to reduce the stress we feel and reduce the chances for obesity.

In the meantime, if you want to avoid stress eating, the best way to achieve this may be to find at least a few moments during the day when you can exist is the state known to reduce the hunger…