Most fad diets that are extremely strict about what you eat, e.g. paleo, keto, etc.

These diets do work if you want to lose weight, at least initially. But people don't lose weight because of the magic combination of fat dissolving foods. They lose weight because the foods on these lists are generally much healthier than what they were eating before and more satisfying than those processed and other junkier foods full of salt, sugar, and bad fats that make you want to eat more of them rather than be satisfied. They are generally a way to trick yourself into eating fewer calories, eat fewer calories, you will lose weight. The problem with this diets is that they are not sustainable. And when people "fall off the wagon," it's not into just eating some other forbidden foods, it's going right back to where they began. Even Opra yo-yo dieted for years, even whole staff of people to make her foods on her special diets so she never needed eat anything else.

The only way to lose weight and keep it off is to be more active and consume fewer calories. If you eat a healthy, balanced diet of lean protein and healthy fats and unprocessed starches including lots a lot of green vegetables plus a fair amount of fruit, and cutting out most of the sugar and processed foods, you will likely find it a lot easier to consume fewer calories because these foods are more satisfying. Anyone who tells you differently is trying t make money off you by showing fast but unsustainable weight loss.