Parenting help

I’ve been trying to keep TV, iPads, etc to a minimum at my house with my two kids (ages 4&2), but I wonder if it is backfiring. I take my kids to the gym everyday, and they always watch TV the entire time there (and they are frequently the only kids watching TV, which is what makes me wonder if I am being too restrictive, and it has increased their desire to watch it?).

This applies to eating as well. I’ve seen huge progress in my eating habits since I quit eating sugar and started eating only based on the hunger scale instead of eating emotionally. It has brought me so much joy although it isn’t always easy. My compelling reason to eat as you teach is that Eating this way gives me SO much more energy. However, my kids don’t understand or feel this same compelling reason. They could care less if they had more energy. I only keep healthy food in my house, but they get unhealthy food almost daily at school, with grandparents, and somehow they always walk out of the store with a lollipop the cashier gave them. Should I try to restrict these times, and tell grandparents/cashiers/etc that they can’t give my kids unhealthy food? I don’t want to increase their desire for it (like the TV), and I also realize that they don’t understand why eating healthily will benefit them. What is a parent’s role (especially of young children)?