I H.A.T.E. mealtimes

Even though I've taught the girls not to use the word 'hate' and instead use 'dislike', I really hate the girls' mealtimes with a vengeance. More of Lavigne's than Louisa's. You see, I have to keep telling them to 'eat', 'sit properly', 'get back on your chair', etc etc etc. Lavigne fidgets alot. She will have her legs up on her chair, or she'll face the back of the chair or worse still go onto her bicycle or scooter in the middle of mealtimes. I've tried many methods. Bribing - 'if you finish you meal, you will get to eat _____', stickers as housepoints, setting a reasonable time for her to finish (health visitor said 20min is more than enough, I give her 45min), no food/snacks threats or simply taking her food away. I get so stressed up at the dinner table. I'd have finished with my food and then just sit there and nag. A waste of my time and energy. I'd been asked before what's wrong with feeding them. Simple answer. One's 3 and the other's 5! They are no longer babies. No way am I going to feed them! If they fidget and are not interested in eating, then perhaps they are not hungry. Once we start spoon feeding them on a regular basis, they will rely on that and won't eat themselves. I worked so hard to get Lavigne to self feed eversince she turned one so I will not go back to those spoon feeding days. They don't get to snack much in between meals. I'd already reduced their snacks to just fruits or one or two biscuits. I don't know what's the problem. Apparently, I'm not alone. Some of my friends are facing the same problem.