When you take a break from eating, your body burns more fat. So yes, not eating — perhaps the most classically employed method of weight loss — in almost all cases, is still the safest and soundest option for weight loss.
In order to understand how fasting assists in the process of burning fat, you need to first understand how fat burning works. To burn body fat, you must get fatty acids out from hiding (out from stored body fat, that is) and into the bloodstream (a process known as lipolysis). You can initiate lipolysis in a couple ways:
Exercise
Fasting (yes, not eating)
But you're not done yet. The fatty acids must then be burnt off (a process known as oxidation) in the mitochondria of your muscle cells. After the fatty acids are burnt off, they're dead. Gone for good. Sayonara.
Fasting increases lipolysis through a sort of default. That is, as soon as your body is done digesting its last meal, it then begins lipolysis for sustained energy, releasing fatty acids into the bloodstream. This process may start to happen as early as two hours into a fast. The longer you fast, the more fatty acids are released into your bloodstream — up to a point, of course.
But again, releasing fat into the bloodstream isn't enough. Eating too soon may actually drive those fatty acids back into storage in a process known as re-esterification. To ensure that the fatty acids are burned up, you must stretch your fasting periods to various lengths, to allow the oxidation process to take place. If you really want to kill fat dead, then you ought to add exercise into the fasted state.
In 2005, the American Society for Clinical Nutrition featured a study on alternate-day fasting — which is a full fast every other day — on nonobese subjects. After 22 days, the subjects lost, on average, 2.5 percent of their body mass. What's more interesting is that they lost, on average, 4 percent of their initial fat mass.