Is my 3-year-old just going through a phase now, when he refuses to eat?
Your job is to offer your son kid-friendly, nutritious meals and snacks and his job is to eat them. You can't force him to eat, and you can never win a food battle, so don't try. At this age, most children are picky, erratic, skimpy eaters, and drive their parents nuts. Their rate of growth is slower than earlier and it's more important for them to be in control of something (i.e. food) to exercise their own autonomy and independence. The real criterion here should not be what is he eating but whether he is maintaining a steady growth rate. Your health care provider can tell you that, or you can plot his growth on the charts
on this site.
Stop making it exciting for him to wage a food battle. Back off. The ability to upset the whole household is too much power for a 3-year-old. It may be that the family stress is contributing to his need to push the limits in this area. If the dinner table is the situation when he gets the most attention, he'll continue to raise a fuss. Give him attention elsewhere. Spend evening times with him, on his own terms. Go for a messier house and simpler meals. Most 3-year-olds do very well in day care, but if his day is very long, you might explore how one of you might pick him up earlier - 4 pm instead of 6, for example. That little change might make a big difference.