The effectiveness of the diet depends on various factors. The food, the duration of the plan and meal composition are critical.

Food

This is the factor we know best today, because we know exactly what each food contains, close to the calorie.
Time is also a key factor

The distribution of meals during the day plays an important role and is not yet fully elucidated. It is likely that one can lose weight by changing the distribution of food and, especially, by giving more importance to breakfast. We know, for example, that equal quantities of food, laboratory mice fed once or twice during the day grow, while those who are fed four times keep the same weight.
The composition of meals has long been discussed

Should we encourage the carbohydrate in the diet as usual, or may otherwise be forced on fats and proteins as in some plans? In fact, when comparing long-term diets different, the results are almost identical. All plans are losing weight the first month and are followed by a rebound weight gain. Few people can control their weight throughout life.

The key to success lies not only on food. To lose weight, it is imperative to move and exercise.