What is the opposite of "gain weight"? Could you tell me more expressions related to "weight" if you can think of any?

Rebecca

The expression "lose weight" here is the opposite of "gain weight". The process of losing weight is referred to as "weight loss", and the process of gaining weight is called "weight gain." If you lose too much weight, you may become "underweight", whereas if you gain too much weight you might become "overweight". Ex: The doctor said she is underweight, but no matter how much I feed her, she won't gain any more weight. Ex: My dog is very overweight, he needs to exercise more so he can lose weight.