Sweet potato has a high starch content, and of course it will gain weight. It doesn't matter what you eat to gain weight. This is a question of how much you eat. No matter what you eat, you can lose weight as long as your calorie intake is lower than your calorie intake. I've lost weight before, but if you break your eating habits, unless you completely change them in your life, it will only be a month or two or a year or two, which is useless. As long as the original diet is restored, it will rebound. So as long as you eat relatively little and have low calories. Don't ask too many questions.