it’s just calories in vs calories out. A better diet paired with more exercise.
Get an idea of how many calories you burn in a day (you can search for a BMR calculator to give you a ballpark), and eat less than that. I started going on runs, and eating a slightly healthier diet.
If you eat less calories than you burn, you will lose weight. That’s just science - that works universally. I don’t really think these fad diets are a good way to view health. There’s a lot more to a healthy diet than just losing weight - your body needs carbohydrates, in fact carbs should be your primary source of calories and foregoing all carbs isn’t a healthy way to lose weight.