Answer : 1. "alter"
Explanation :

• "Alter" means to make changes or modifications. In this context, it's used to convey the idea of adjusting or changing the outfit to accommodate the person's change in weight.
• "Altar" refers to a raised structure or platform used for religious or ceremonial purposes.
• "Ultra" means beyond, extreme, or excessive, and it doesn't fit the context.
• "Utter" means to speak or express, and it doesn't convey the idea of making changes to an outfit in this context.