The main reasons for not being fat may be heredity and living habits. The basal metabolic rate of this body type is extremely high, and the leptin gene is active, which basically makes obese cells despair.
However, we should also carefully observe the details of some living habits, whether to do more exercise in places you can't see, don't wolf down when eating, or have our own principles in food selection to avoid some pits that are prone to obesity.
Moreover, eating fat is relative, not absolute. When I was young, I ate fat, and my metabolism decreased in my 40 s. Many people soon went bald and had a beer belly.
For example, even the thinnest person, if fed by the Japanese sumo training method, will certainly be able to achieve gorgeous transformation and fulfill the desire to eat fat!
Eat a balanced diet, exercise moderately and have a good rest. Fat and thin is a game between human metabolism and energy intake. Being born fat doesn't mean being a winner all your life. Good living habits will make you always have a beautiful and healthy weight and become an enviable object.