Leptin hormone? What?
It’s name is Leptin (derived from the Greek word leptos, meaning “thin”), and it’s without a doubt the most important hormone you probably never heard of.
You see, leptin was only first discovered just over 10 years ago, and as far as weight loss is concerned, that’s extremely recent.
Leptin’s function? To communicate your nutritional status to your body and brain.
Leptin levels are mediated by two things. One is your level of body fat. All else being equal, people with higher levels of body fat will have higher leptin levels than those with lower levels of body fat and vice versa.
Because the leptin hormone is secreted by fat cells, it makes sense that under normal conditions there is a direct correlation between leptin levels and the amount of fat you are carrying.
Unfortunately, when you’re attempting to lose fat and begin to restrict calories, conditions are anything but “normal” and the body responds accordingly by lowering leptin levels.
This is because the second mediator of blood leptin levels is your calorie intake. Lower your calorie intake and leptin will fall, independent of body fat.
So, yes, you can be overweight and still suffer from low leptin levels – just go on a diet.
So what happens when leptin levels fall and why the heck does it matter?
Again, under normal conditions leptin levels are normal and the brain gets the signal loud and clear that nutrition intake is adequate. Metabolism is high and the internal environment of the body is one very conducive to fat burning.
Until you start dieting...
Go on a diet and leptin levels quickly plummet (by 50% or more after only one week), sending a signal to the body that you’re semi-starved and not consuming enough calories.