From the research I’ve done recently, it would seem that burning fat isn’t related to calories as much as it is to hormones.
Our bodies are pretty fantastic at adapting to different daily caloric intakes, which is why people who lose weight on low-calorie diets often gain it back after a while. If you eat 1,200 calories a day, your body starts to utilize those calories more efficiently, and 1,200 becomes the new standard. You might lose a decent amount of weight before the adjustment, but if you go back to a 2,000-calorie standard afterwards, you’re going to start packing on pounds again.
The idea isn’t to restrict caloric intake, but to restrict yourself from constantly telling your body to store fat. Every time you eat, and especially if you eat carb-heavy foods, your insulin spikes, which is essentially a signal for your body to start storing fat. If you’re eating 3 meals a day, and snacking in between (which many nutritionists sadly recommend), you’re basically keeping your body in a constant state of fat storage.
Eating once a day not only tells your body to use up what you’re putting into it, but depletes glycogen in your liver which results in your body turning to your own fat for fuel.