If you're staying in accommodation which sells food you may be restricted on where you can eat your own food, whether it's from a takeaway or the local supermarket makes no difference. If you have a pool then it's likely that there will be a pool bar selling drinks and snacks. It's common practice not to allow guests to consume their own food and drink in the pool area, you must buy it from the bar. It might sound unreasonable but the reality is that the holiday companys pay a relatively small amount for the rooms and income from selling food and drinks is essential to the business. If the pool bar closes in the evening then you shouldn't have a problem but otherwise you may have to consume your takeaway in your own room or balcony. If the accommodation you are staying in doesn't sell food then you shouldn't find any restrictions on where and when you can eat your takeaway.
Zante Takeaway 2019
It's like 'Just Eat' but for Zante