Leptin is a hormone that decreses appitite, its produced in the fat cell itself and is part of a thermostat like cell system that maintains weight at a constant level. Its like a fat watchdog that monitors body fat and will start up to correct a percived inbalance in your body fat. Loose weight and Leptin levels fall prompting you to eat more and gain to much weight and Leptin goes up and you eat less.
Its part of an intricate biochemical and neurological circuitry that flashes signals on and off like a lighthouse warning… EAT..STOP EATING…EAT….STOP EATING!
Some people eat to fast and as it takes 10-15 mi nutes for the brain to register the leptin signals by the time that happens, they have already eaten far to much for the signal to be heard.
Leptin resistance is the erratic fluctuations of leptin and the hormone ghrelin which makes you feel hungry. This resistance complicates your ability to loose weight and triggers intense hunger. The imbalance of Leptin hormone, can impede weight loss even in the presence of proper levels of estrogen, progesterone and thyroid. You might have adequate levels of leptin but your body may be desensitised to the hormone and resistant to Leptin. This is called Leptin Resistance and is caused by long continious abuse of food and overeating all thoses delicious processed foods.
You can have a blood test done to determine your Leptin levels. If you normalise it through healthy eating, excersise and proper portion control plus never going to bed on a full stomach, your body will start to burn fat.