There are gut health benefits to feeling hungry that show avoiding hunger is a bad idea. Unfortunately, many people experience hunger when they work to address their circadian rhythms. For the most part, syncing up circadian rhythms causes a person to feel better. This includes:
- A positive emotional response
- Better digestion
- Increased alertness and energy in the morning
- Healthier blood glucose levels
- Improved sleep
People experience hunger during the first week or 2. It’s not an overwhelming sense of hunger, but enought o cause some people to quit. Unfortunately, I think this causes people to miss out on many of the gut health benefits of hunger.
Nobody likes to be hungry. I don’t believe that the hunger one feels is an overwhelmingly negative sensation when syncing up your circadian rhythms. But, it takes some adjustment, particularly if you eat 4-5 meals per day.
However, this is simply a negative association that we created with hunger. Hunger actually plays a substantial role in optimizing our physiology. Without hunger, our ancestors would have never known when to look for food or when to eat. And data shows that the hunger hormone ghrelin plays a pretty big role in telling our body what time of the day it is.
This is crucial because telling the body when food is coming can tell our body to prepare for the inflammatory onslaught to come. At no other time of day will things that cause inflammation come in to closer contact to our organs. Foreign objects such as food and bacteria on our food cause our immune system to go nuts.
Being able to anticipate when this happens can give our body a chance to prepare. Ghrelin is a hormone that helps us do just that. Eating is an inflammatory event, and ghrelin helps:
- Pump the brakes on inflammation
- Prepares our gut to digest food
- Readies the gut to kill bacteria
- Seals up the gut and blood brain barrier.
Ultimately, ghrelin gets the gut in tip-top shape to digest our food and keep bacteria out of the blood.
Gut health benefits of ghrelin
Aside from promoting the unpleasant sensation known as hunger, ghrelin actually has some pretty cool beneficial effects. The stomach secretes ghrelin during prolonged periods of fasting and in anticipation of scheduled meals. Of course, since it gives us the sensation of hunger, ghrelin doesn’t just sit in the stomach. It travels throughout the body and even crosses the blood-brain barrier. It’s a circadian signal to prepare for food.
So what does ghrelin do? Well, first, when ghrelin rises, there’s an increase in gastric mucus production and acid secretion. Essentially, it ramps up our ability to digest proteins in the stomach, and increases the barrier that prevents stomach acid from destroying the cells in the stomach.
Ghrelin also promotes motility, both in the stomach and in the small intestine. This makes sense, it’s essentially clearing everything from the prior meal by stimulating the migrating motor complex which acts as sort of a housekeeping system for the gut. The longer food stagnates in the gut, the greater the risk of small intestinal bacterial overgrowth(SIBO).
Ghrelin vs leaky gut
Ghrelin also prevents leaky gut. Again, it makes sense that a hormonal signal that syncs up with anticipated meals would prepare the gut It also increases the strength of the blood-brain barrier AND gut during traumatic brain injury. This indicates that properly applied fasting MAY be a valid strategy to recover from brain injury.
While floating around in the circulation, ghrelin also helps stop inflammation. When exposed to ghrelin, macrophages shift to an M2 state. Macrophages can be either inflammatory or anti-inflammatory, polarized to an M1 or M2 state respectively. Ghrelin maintains macrophages in an M2 state to inhibit inflammation. The association between chronic inflammation and obesity is partially explained by a decrease in ghrelin levels.
As you can see, ghrelin is a lot more than a hunger hormone. It’s a circadian signal that helps sync up the feeding period with the circadian clock to help optimize physiology to the environment.
Ghrelin is definitely a hormone worth looking at beyond its effects on hunger. We automatically associate hunger with negative emotions. But given the physiological effects of ghrelin, experiencing it on a regular basis may be a good thing.
Since higher ghrelin levels signify greater hunger, hunger may be a sign that the gut is prepared for food. This doesn’t necessarily mean that lack of hunger means it’s not ready for food, but it’s telling that obese and insulin resistant people have:
- A leaky blood brain barrier
- A leaky gut
- Chronic inflammation and enhanced M1 macrophage polarization in fat tissue
- More than 2x more likely to develop gastritis
Obese people also have lower ghrelin levels which increase as they begin to lose weight. Interestingly enough, a recent study found that when obese women cut their calorie intake to 800 cals/day, their leaky gut and systemic inflammation improve. The beneficial effects are lifted when calorie intake is increased back to baseline.
So maybe we should embrace hunger as a signal that the body is prepared for food, and not try to avoid it like the plague. There appear to be many gut health benefits to experiencing hunger.