Sugar impacts the brain just as much as the waistline. In this episode, Dr. Robert Lustig explains the biochemical shifts that sugar causes, making us store fat and feel hungry at the same time.
The hormone leptin goes from your fat cells to your brain and tells your brain that you have had enough to burn energy at a normal rate. It limits what you eat and lets you exercise. An obese person has high levels of leptin because of the excessive fat cells; this leads to leptin resistance, meaning that the body stops responding to the message sent by leptin. As a result one eats beyond being full. The industrial global diet introduces excess insulin into our bodies. The hormone insulin drives weight gain because it converts sugar to fat. Sugar is immediately converted to fat without giving one the chance to burn it. This causes a person to overeat because the body still wants to burn x amount of calories and those calories that the insulin converted immediately to fat don't count towards one's daily intake. Insulin blocks leptin at the brain so the higher one's insulin goes, the more energy is stored instead of burned, and the hungrier one gets.