What is the most common cause of people gaining weight? Don't take this as an excuse, but... The problem of being overweight is 66% hereditary. Not all people with it become chubby, but it is much harder for them to maintain a normal weight. Excessively large portions or high-calorie meals, late large dinners, a passion for refined carbohydrates, carbonated drinks... All these things are very dangerous for them☝🏻