Not sure how to find my Why

I am finding it difficult to identify a compelling why for weight loss. A why powerful enough to motivate me to feel the urges and not act. Are there questions I can ask myself to uncover powerful whys? I’m at a healthy weight and really just want to lose 10lb to fit into certain things and prove to myself that I can do it- so it doesn’t seem wildly compelling. I’d like to identify authentic whys for a range of goals. Any advice? Thanks