He will eat when he is hungry. It's just a matter of how long you can hold on.

Also include them in the prep. Ask him before dinner what he would like. Ask him to measure out the pasta or rice into a bowl so he feels a part of the meal. Throw the biscuits in the bin. If he's not old enough to show restraint and he has more stamina than you then don't buy the biscuits. Buy foods that are always foods. Have a container of snacks in the fridge or pantry that he can eat at anytime. It doesn't sound like this is about food at all. It sounds like he feels he doesn't have much power in his choices. It might be time to start offering him more choices in all aspects of his life. We only fight against authority when we feel we have no control. So maybe offer him some more control in other areas of his life and you might find meal times are less stressful. Try and watch your interactions during the day. See how often you tell him what you are doing, wearing, going etc. and see if you can change it around so that he can feel a part of the process. Rather than a passenger in your life. It's a hard balance but getting that balance helps for a happier child and household