Leptin and brain dysregulation.
If you follow us on Facebook, then you would have seen a headline to a study about obese teens and leptin levels that I put up. The title of the study “Obese teens with high leptin levels have increased brain response to food cues” was published in the Diabetes Care Journal.
I talked a lot about leptin on our last podcast, if you haven’t listened to it yet then I would encourage you to do so. In summary, Leptin is a hormone that is produced by fat cells. When your cells secrete leptin, it travels to your brain and tells it that you are full. Your brain then speeds up your metabolism, increases your energy output and increases your thyroid hormones. The reason is simple, your body is trying to maintain your weight, and your fat cells are telling your brain that you are full, you are fed, better speed up metabolism to burn the extra fat in order to keep your weight at the same level.
The amount of leptin you have depends on how many fat cells you have. We have a built in mechanism that is designed to keep your weight healthy. If we have leptin, how then do we become obese? If the job of leptin is to speed up metabolism, and the more fat we have the more leptin we have, why in the world do people have a hard time losing fat? (Also, we also talk about the stupidity of calories in and calories out on the podcast. Any doctor or health care practitioner who says eat less move more to lose weight is completely undermining the hormonal aspect of fat loss.)
The reason why people can become obese is due to the fact that they become leptin-resistant. Just like insulin-resistance, the body ignores the hormone. In the case of leptin, the brain stops responding to it. This means that even though you are storing fat and secreting leptin, the brain doesn’t see it. As a result, the counter hormone ghrelin is able to influence your body. Ghrelin is the hormone that your body secretes when you are losing weight. Ghrelin tells your brain that it is hungry. Ghrelin slows down your metabolism and thyroid so that you stop losing weight.
When someone becomes leptin-resistant, even though they have a lot of leptin, their brain is telling their body that they are hungry. Not only that, but a person with leptin resistance will have a slower metabolism. This person is a victim of their hormones.
The study that I mentioned earlier showed that obese teens with high leptin levels (the fact that they are obese and have high leptin levels tells you that they are leptin-resistant) also have a significant increase in neural responses to images of high-calorie foods. This is incredible. This means that obese teens with high leptin levels are more stimulated to eat high calorie foods when they see those types of ads.
Obese teens have no chance. Not only are they leptin-resistant and can’t simply “eat less and move more”, but the area of their brain associated with reward motivation is dysregulated making them more likely to chose bad food. Food companies have contributed to their obesity and also makes it more likely that the obese teen will eat their food as a result.
Food marketing to kids should be banned.
Leptin levels are strongly correlated with insulin-resistance, this is why we strongly recommend biomarker testing for anyone who is having a hard time losing fat.