If you’ve lost weight, only to gain it back, you may be all too familiar with your hunger and satiety hormones. Leptin and ghrelin are your body’s main hormones that regulate when you’re hungry and when you’re full and may be the key to your metabolism and body weight.
Leptin is what makes you feel full:
It’s secreted by fat cells, and the more fat you have, the more leptin is secreted.
Leptin signals to the thyroid that there’s adequate fat so you burn it off instead of keep storing it up. The problem that comes into play with obesity is that you can develop resistance to leptin over time.
Your body may think you’re starving because of leptin resistance, or because you’re not eating adequately (such as when you’re on a too restrictive diet). So, what happens, then?
You increase fat storage instead of burning and burn less calories overall.
Your appetite increases, you don’t feel satisfied, and you’re more likely to overeat.
You’re more likely to develop insulin resistance.
If you’ve been overweight for awhile, it’s harder for you to lose weight. But it’s definitely not impossible. This is where activity plays a major role in helping to burn off more calories and stabilize your hormones.
Ghrelin is the “hunger gremlin” hormone, because it’s the one that increases your appetite:
It’s made in your stomach and tells your brain to eat or drink when your stomach is empty.
It also controls genes that hold on to fats instead of burning them off.
Research shows that when you’re sleep deprived, your ghrelin levels are elevated, and leptin levels are depressed, which is why you’re hungrier after a few sleepless nights.
Studies also suggest that when you skip breakfast, high-calorie foods are more appealing to you due to the ghrelin’s powers.
Your response to these hunger hormones may differ from the person standing next to you. Just as everyone’s metabolism is different, the way a body copes with stress and hormones and nutrients isn’t the same for everyone. Your environment, diet, and lifestyle can affect how your metabolism reacts, and that’s what this book addresses.
On some level, metabolism can be a mystery, but you can take actionable steps to change the hand you’ve been dealt.