My coworkers eat my lunch every day

I’m close with five other coworkers at my company, all of them are married, carefree, and chilled.

They are comfortable with using one another’s belongings, from nail clippers to lipsticks and eye drops. They especially like to share things they prepare for lunch with one another.

I was comfortable sharing my meal with them during my first working days, and thanks to that, I got a lot of help from them. But I didn’t expect that they would keep asking for food from me even after we got closer.

Every one of them asks for something from my lunch everyday, from meat to rice and vegetables. There was even one time when one of them texted asking me to bring more food than usual so that I could share my meal with her since she had not eaten at home the day before.

While I enjoy cooking, I am uncomfortable that they constantly ask for food from me.

What should I do?