Your body loves redundancy. In fact, that's one of the major reasons why there are so many different approaches that can be taken to fat loss. But, one of the major diets of today relies on one state of fat burning that is worth analysis.
This diet is the ketogenic diet, which promotes fat loss through minimal carb intake and maximum fat and protein intake. As a low-carb, high-fat (LCHF) diet, the ketogenic diet is able to get the body into a constant (or near constant) state of "ketosis".
Ketosis can be seen as the body's back-up way to get energy. Primarily, the body prefers to get energy from the carbs that you consume each day.
That's because carbs are quick and easy for the body to convert into glucose (sugar) which then allows the body to send energy to your muscles as quickly as possible, with as little delay as possible. This is why many athletes emphasize the importance of loading up on carbs, especially before a hard performance.
Ketosis, however, is another way for the body to get energy. When your body has no carbs to process, it jumps to its backup source of energy: the fat that it stores all throughout your body.
Ketosis is the process through which your body transports fatty acids to the liver where they are processed and turned into energy. In simpler turns, it's how your body burns the fat that you likely have hanging around on your arms, stomach, and legs.
This is a completely natural state of being and, by limiting your carb intake, you can maximize how many hours of the day your body spends in ketosis.
The more hours your body spends in the state of ketosis, the more fat your body will be able to burn. This is why many people promote low-carb diets as the epitome of weight loss diets. After all, when you're burning fat around-the-clock, you are most likely going to see quicker and more steady results.
Some of the benefits people promote alongside the ketogenic diet include sustained fat loss and a lack of plateaus.
In fact, if you are "stalled" in your weight loss journey--meaning you haven't seen the scale budge for a while--many types of diets promote a "fat fast" where you cut the carbs for 1-7 days and up your fat and protein intake (sort of like a short ketogenic diet) in order to get your body into fat-burning mode and move past your stall.