How Hunger Works

Hunger is a pretty basic part of the human experience. And, as such, people tend to take the entire mechanism for granted – going through life with only a cursory understanding of how it works.

But…who cares? Why does it matter how hunger works? Because hunger, logically, drives how much you eat and can greatly influence the degree of success you enjoy (or don’t) in your fitness pursuits. As we’ll see, the system that controls hunger can be powerfully affected by a variety of lifestyle choices.

So, a deeper familiarity with hunger will give you the information you need to better control this system so that it works for – rather than against – you.

The Major Players

On it’s most simple level, hunger is controlled by two hormones: leptin and ghrelin.

Produced by fat (adipose) cells, leptin is essentially responsible for changes in your weight over the long-term. Basically, the more adipose that you carry, the more leptin that you produce. Leptin levels also spike after you eat. (This will be key when we apply all of this information later on.)

That leptin then travels through your circulatory system to your brain, where it lets your hypothalamus gland know that you have plenty of stored energy and don’t need to eat any extra. As a result, you feel full.

Ghrelin functions similarly but, since it’s produced by your stomach, it deals with more immediate information. When the amount of food in your stomach is low, ghrelin levels increase. The hormone then makes that same trip up to the hypothalamus and informs your brain about the situation. Based on that signal, you start to feel hungry.

It’s important to know that when ghrelin levels are high, your brain produces a substance called neuropeptide Y. This neurotransmitter is actually what lets you know it’s time to eat and is specifically responsible for carb cravings.

Interestingly, these two hormones oppose each other. When leptin levels are high, ghrelin is suppressed – as is neuropeptide Y. As ghrelin increases, though, leptin drops.

Lost Signals

The trick to weight control, generally, is hunger control. And, hunger control is all about these two hormones. Unfortunately, things don’t always work the way that they’re supposed to. If they did, obesity simply wouldn’t be an issue. When your adipose tissue started to grow, your leptin levels would increase and you wouldn’t be hungry.

Of course, that’s not what happens. So, what’s the problem?

Often, when levels of a certain hormone are frequently and chronically elevated, your brain stops listening to those messages. This is true in the cause of insulin and type II diabetes. Things go the same way with leptin.

Frequent over-eating will keep your leptin levels high and, in turn, your brain will start to tune that particular hormone out. Since leptin is tasked with sending signals of satiety, this state of leptin resistance leaves you chronically hungry.

Leptin resistance can be reversed, however, by losing body fat. Because of the cycle of hunger, though, this can be extremely challenging.

This hormonal system can also be disrupted by lack of sleep and chronic stress.

Putting It To Use

Of course, there are also emotional triggers that can make you feel hungry.

The lesson? Hunger is not always a trustworthy signal. The “listen to your body, eat when you’re hungry approach,” doesn’t always work.

For those struggling with constant hunger, tracking their calories is generally the best, most objective method – even if it can be time consuming.

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