How Does Intermittent Fasting Work?
The science behind intermittent fasting relies on the fact that when we eat, our insulin levels spike. Insulin is a hormone that's released when we eat, but it isn’t meant to be released all the time. It’s hard for your body to lose fat while your insulin levels are high. But after 8 to 12 hours after your last meal, you enter the fasted state. It is much easier for your body to burn fat in the fasted state because your insulin levels are low. And when you're in the fasted state your body can burn fat that has been inaccessible while your insulin levels were high.
Since the body doesn’t enter the fasted state until 12 hours after our last meal, it's rare that our bodies are ever in this fat-burning state. This is one of the reasons why many people who start intermittent fasting will lose fat without changing what they eat, how much they eat, or how often they work out.