What Leptin Is
Leptin is a hormone secreted by adipose tissue (fat cells) that tells you you’re full. (Its opposite hormone is called ghrelin, which tells you you’re hungry. You can remember this because the word ghrelin sounds like a stomach growling.) Because leptin is secreted by fat cells, you produce more leptin as your weight increases. Ideally as you gain weight, the increasing leptin would tell you, “Stop eating! We don’t need to store, we need to burn!”
How Insulin and Leptin Are Linked
Insulin and leptin are (essentially) both produced because of sugar. Eating too much sugar makes you gain more fat (see causes below – which leads to more circulating leptin), and sugar also forces your pancreas to pump out more insulin so that the sugar can get into the cells.
What Leptin Resistance Means
Resistance to signaling hormones (such as insulin or leptin) works essentially like “The Boy Who Cried Wolf.” If he’s screaming all the time, after awhile people start to ignore him. He has to keep screaming louder to get anybody to listen to him the next time.
In the case of insulin resistance and diabetes, if you eat enough sugar for long enough, your body will pump out more and more insulin to keep up with the demand, and eventually your cells stop paying attention to their signal because there’s so much of it floating around. In the same way, as you gain weight, your adipose tissue pumps out more and more leptin. Eventually there’s a point at which the regulatory message gets ignored. (Familiarity breeds contempt!)
Unfortunately if the message is ignored, that means ghrelin’s opposing message prevails — which is that you’re starving. Your body then goes into storage mode, rather than burning mode. So leptin resistance is linked not just with obesity, but with all the trappings of obesity, including hight blood pressure, heart disease and stroke, and blood sugar problems. It can also be linked with lower fertility (since it’s telling your body that it doesn’t have the caloric resources to support a child.)
What Causes Leptin Resistance?
In a word, sugar (and all of its permutations – see #1 below), because sugar makes you fat.
Think of sugar as quick energy. It can get converted into the currency your body uses for energy very quickly. But the flip side is, you can only have so much of it on hand — your blood can only accommodate a few tablespoons of sugar at a time. Your body needs to get rid of any excess quickly, before it causes vascular damage or hyperglycemic symptoms.
So when your body has to get rid of it, where does it go?
There are only two compartments in your body: intracellular (inside the cells) and extracellular (outside the cells). The bloodstream is outside of the cells, so sugar has to get inside the cells in order to get out of the blood. (This requires insulin.) But cells can’t store sugar in its present form, so as soon as sugar comes into the cell, it gets converted from “quick” energy into “potential” energy — fat. And, as we mentioned, the more fat cells you have, the more leptin you produce. And the more leptin you produce, the more resistant your cells become to its signal.
Other factors that decrease metabolism and cause the body to store the excess glucose as fat include stress (leading to high cortisol, which leads to high blood sugar), and lack of sleep (which also decreases the body’s metabolic rate, and increases cortisol.)
How You Counteract Leptin Resistance
- Cut out added sugar. Eating sugar is what makes people gain weight. Read labels, and if you see any words ending in “-ose” (sucrose, fructose, dextrose, maltose, etc), anything ending in “syrup” (especially High Fructose Corn Syrup), cane juice or fruit juice concentrate, honey, agave or anything of the sort, avoid it.
- Cut out processed white carbs. These turn to glucose the second they hit your saliva. They’re the same thing as sugar.
- Have some protein with every meal. This will slow the release of glucose into your bloodstream, helping to stabilize blood sugar and dampening the vicious insulin/leptin cycle.
- Take your fish oil. This will help keep cell membranes healthy, which will enable them to hear and respond to cell signals (like insulin and leptin). Just make sure you get a good one – they’re not all created equal.
- Get enough sleep. Sleep is so critical for metabolism (and health generally) that it deserves its own article. Here it is.
- Chill out. Stress and anxiety, as mentioned above, increase cortisol, which is bad news for your adrenals as well as your weight. Here are some practical tips for reducing your stress levels on your own.
- Exercise. If you are leptin resistant, you may not get great results with this at first. This is because when your body is in starvation mode, it’s hoarding: it refuses to burn its energy to feed your muscles even when they need it, and that means your muscles get fatigued faster. Start with resistance (weights) first, since weight lifting “turns on” metabolism by pumping out Growth Hormone (GH). You will begin to lose weight when you no longer feel like you’re always hungry, craving carbs, and exhausted – this means your metabolism has “turned back on.” That’s the time to add in cardio regularly.
Although it is possible to test leptin directly, it is also useful to test rT3 (reverse T3, the inactive form of the metabolically active thyroid hormone. Your body increases its production of rT3 when it is trying to slow down its metabolism.) Your naturopathic doctor can run these labs for you, and give you more personalized guidance on how to reverse leptin resistance.