The Physiology of Insulin: The Poison of Plenty

Insulin and Calories: Biochemical Blindness

Imagine you are counting calories with the goal of losing weight. You decide to cut out 25% of your calories and spread out your meals throughout the day. What does this translate to in terms of hormones? Well, every time that you eat, your body gets a small dosage of insulin to control blood sugar. However, this hormone signals the body to store fat. If you eat throughout the day, this means your insulin levels are elevated regardless of how many calories you consume. 

Since insulin is high, the body is chemically unable to break down fats. However, the only other energy source is the incoming food, which has been reduced. Thus, the body has no choice but to slow down the base metabolism in an attempt to meet energy demands. Amazingly, the high insulin makes the body “blind” to the vast energy stores present in the surrounding fat. This is the equivalent of being on an island in a lake and only relying on rain as a water source. This is why traditional dieting does not produce efficient results; the body simply did not evolve to be constantly eating food throughout the day. The effects of eating constantly throughout the day also explain the obesity trend in the modern era. 

Obesity and Body Set Weight

The best analogy of calories and body weight I have encountered was in The Obesity Code by Dr. Jason Fung. He explains the physiology of insulin and the leptin-insulin hormone balance by comparing it to a thermostat. At rest, the hormonal system balances our body weight through natural homeostasis. Leptin levels rise if we are too fat and decrease when we are not, allowing us to eat again. This is like setting a thermostat to a certain temperature; the AC will turn on if its too hot and the heater will kick in if it’s too cold. 

Losing weight is like lowering the room temperature. Normally, all you would do is lower the thermostat setting to a lower temperature (lower insulin levels). However, the less intuitive way is to bring in more portable ACs. This will lower the temperature, but the thermostat will still be fighting to bring the room back to baseline. This is exactly the case with calorie counting. Unfortunately, in the case of obesity, this thermostat is completely broken. Here’s how:

Breaking Homeostasis: Processed Foods

We all have heard that sugar increases insulin. Whenever you consume carbohydrates, insulin levels shoot up like crazy. This is because keeping too much sugar in the blood is damaging to red blood cells. Thus, insulin tells the body cells to absorb sugar and store it away. When insulin spikes this high, it essentially overrides the leptin signal. In response, the fat cells release more leptin, which slowly results in leptin resistance. As a result, chronic elevation keeps insulin high, telling the body to maintain a higher body weight over time. The longer this goes on, the higher your body set weight calibrates, resulting in obesity over decades.