Feeling hungry? That’s Ghrelin talking.

Not to be confused with gremlins—the nasty creatures that result from feeding a Mogwai after midnight, according to the 1984 film, Gremlins.

Some of you, including my wife, weren’t even born yet and probably won’t get the reference. But let me say, the way many people respond to a spike in ghrelin isn’t much different than how gremlins behave. (Go to YouTube and you’ll see what I mean!)

Ghrelin is known as, the hunger hormone.

When ghrelin is secreted by your stomach (because your stomach is empty) it increases your appetite and encourages fat storage.

Conversely, the hormone Leptin tells us when it’s time to stop eating.

Leptin—which is secreted by our fat cells—tells us that we have enough fat so we can slow down or stop eating.

However, like many of our beloved family members and friends—Leptin has some issues.

First, when a person gains fat their leptin increases. Technically, this should be a good thing as it would signal to the brain it’s time to stop eating.

But as we see with insulin, the more it gets secreted the more resistant we become to it. Instead of telling us to stop eating it signals the need for more fat—so keep eating! We get fatter, and the cycle continues.

Issue number two. As a person loses fat or eats less (as in the case of dieting) leptin lowers and this sends to signal to start eating.

If we’ve been eating too little for too long our metabolic rate lowers and when we eat we wind up gaining more weight back than we lost.


To say leptin can be a bit temperamental would be an understatement.

Controlling hunger means taking control of ghrelin and leptin.

Here’s the most important thing you need to know about ghrelin. It can be tamed.

The times at which ghrelin rises throughout the day are largely your own doing. You’ve trained your body to feel hungry at certain times.

(Get ready because this is where the skipping breakfast part starts to come in.)

In the study, "Spontaneous 24-h ghrelin secretion pattern in fasting subjects", the subjects fasted for 33 hours. Over that time researchers noted that ghrelin levels naturally spiked around the hours the subjects typically ate and that ghrelin comes and goes in waves.

Even though the subjects did not eat when hunger peaked, ghrelin did not continue to rise. Instead, it dropped spontaneously and hunger disappeared.

Think about the implications of this!

  • If it wasn’t for the fact that we’ve forced ourselves to eat at certain times (Ahem! Breakfast.), our ghrelin levels would naturally be lower which would prevent us from overeating.

  • If we ignore the hunger signal long enough we don’t feel hungry. Do this enough times and we train ourselves not to constantly feel hungry.

  • If we’re not constantly eating we feel fuller faster. It’s unforced portion control!

Fasting intermittently or for extended periods has been proven to be one of the most effective means of lowering ghrelin, and as a byproduct, leptin.

Manage hunger and you can manage fat-gain or loss. Manage body-fat and you’ll manage leptin.

In part 4 we’ll touch on one of two more hormones released when in a fasted state. These two might be the most exciting to those looking not just for long-term fat-loss but a major change in body composition.