At it's heart, weight loss is quite simply eating less calories than we use. But, being human, that's way too easy for us to understand so we seek to complicate things. Whether that's by excluding certain items (sugar, fat, carbs, whatever), eating certain things on certain days, etc.
And being male we tend to like the slightly complicated rules of some diet plans because they seem to help us feel more in control of our ever bulging bellies.