7 year old daughter is losing weight

My 7 year old daughter has lost some weight this summer. She was 55.7 pounds the last time she was weighed at home and that was on 5/18. Tonight I noticed she looked like she was thinning out a bit so I decided to weigh her again and she was 53.7 so she’s lost 2 pounds since May and I’m not sure if it was gradual or more rapid/recent.

Should I be worried about this? She has definitely been more active this summer than she was during the school year. She laid around a lot during the school year. This summer she had spent more time running around outside, riding her bike and scooter. We also took two vacations in June/July and walked, hiked and swam A LOT. Her diet hasn’t changed much and she hasn’t shown any signs of medical issues like fatigue, change in appetite or pain/stomachaches, etc.