You’re Not Lazy

This is an adaptation of an explanation of why people get fat by Dr. Robert Lustig. Kudos to him!


In 1994 scientists confirmed the existence of a new hormone that plays a big role in weight regulation – leptin. Leptin exists in fat cells. Its job is to tell your brain that you’re full. For so many of us, the signal isn’t working. We have become leptin resistant. Only recently have scientists discovered why this happens. Hint: insulin plays a major role.

Insulin is a master hormone. Its levels are a signal to many other hormones and functions. Insulin’s job is to convert blood sugar to body fat. Let’s say a diabetic has high blood sugar. 100 is normal. Let’s say it’s 300. You give them a shot of insulin, and their blood sugar goes down to 100. Where did those 200 mg/Dl (milligrams per deciliter) of sugar go? Insulin stored the energy in fat cells, where it is safer than if it were in the blood. High blood sugar is dangerous. It’s corrosive. It leads to Type 2 diabetes, loss of limbs, blindness, kidney failure, fatty liver, etc.

Let’s say you are a thin healthy happy person. You eat 2000 calories a day and you burn 2000 calories a day. You feel great. Burning calories and feeling good are the same thing. We feel good when we burn calories. So, as an experiment, let’s say I walk around with you all day, and every time you eat – I’ll give you a shot of insulin, just like they do with diabetics.
Just like the IRS taking 25% off the top, that insulin shunts 500 of your 2000 calories away to body fat before it can be “spent.” You’ve now stored 500 calories as body fat, and you only get 1500 calories to burn. You feel tired, lazy, and hungry. You are effectively starving. So, you eat another 500 calories and I give you another insulin shot. 100 of those 500 get stored as fat (600 total) and you only get to burn 400. You’re still not operating at 100%. Can you see how this is a vicious cycle? High insulin means calories that you SHOULD be able to burn get stored as fat. More fat means more leptin, which is screaming to the brain, “stop eating,” yet the brain isn’t listening.


So why doesn’t your brain get the signal? This is where the recent science comes in. Turns out that insulin blocks leptin receptors. Have you ever had the sensation of having a full belly and still being hungry? That’s why.

You may also think: that’s fine, but nobody is walking around shooting me up with insulin all day! The fact is, eating a diet high in carbohydrate raises blood sugar which causes the pancreas to secrete more insulin. Worse, over the years, your insulin becomes less effective. It brings fat to the cells but the cells don’t want it. So it takes more and more insulin to do the job. This is called insulin resistance, and is essentially type 2 Diabetes. Insulin resistance and leptin resistance dance together to promote obesity.

The obvious solution is to reduce the amount of Insulin secreted by your pancreas. You can do that a couple ways. The hard way is to exercise your brains out. You’ve probably tried that. Doctors tell you to eat less and exercise more. Did that work? Clearly, it doesn’t work. The easiest and safest way to reduce the amount of insulin in your body is to reduce your carbohydrate intake.

After only a few days on a well formulated ketogenic diet (low carb, high fat, moderate protein), you will lose cravings for sugar and starches. You will feel better. You will eat less because leptin is able to do its job. Your blood sugar and insulin will drop to safe levels. This IS the way to lose weight, feel good, and stop the progressive train that leads to type 2 diabetes, loss of limbs, blindness, kidney failure, fatty liver, and all that. Turns out toes are better than fries.


Obesity, leptin resistance, and the effects of insulin reduction. Lustig, Et Al.

Video: Sugar, the Bitter Truth. Robert Lustig

Video: The Skinny on Obesity. Robert Lustig

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