For the 1st year of life, breastmilk/formula is the PRIMARY source of nutrition for a baby. NOT solids, NOT juice.
And, per our Pediatrician, for the first year of life, you still need to nurse on demand. THIS is very important.
Right now, "solids" is just an INTRODUCTION. Not a feast. Not 3 meals a day. It is a "process" that is g-r-a-d-u-a-l-l-y worked up to.
And yes, at this age and for the next few months, a "serving size" IS in terms of "tablespoons" or "teaspoons." NOT jars. So, your son is on par.
Certainly also, a baby's taste buds are also STILL developing.. .their full-range of taste buds are not fully developed yet. Even in as a toddler. Thus they are being acclimated to everything, food wise. No worries. It's normal.
Food preferences is NOT static. It changes ALL time. You just have to not "force" it, and learn what makes him tic.... learn what he likes and can tolerate at this age. You must flex according to the child. THEY are the one's "learning" to eat, and learning about foods.
Their tastes will change all the time... heck, even teens and adults go through this. Right? So, it's NO surprise that a mere baby is too.
No, you DO NOT TAKE AWAY BREASTFEEDING IF HE DOES NOT EAT. THIS IS "PUNISHMENT" AND UN-CALLED FOR AND AT THIS AGE HE WILL NOT UNDERSTAND THIS. You do not use food as "punishment." It is NUTRITION... not a psychological "weapon" or "tool" to make a child eat. Much less a baby. You do NOT use food as a way to do this. It will only later create hang-ups for the child at meal-time. You do NOT want that. It is only harmful.
NOW, as for breastfeeding while introducing "solids." You should always offer breast FIRST. If you give breast after, he will be too full to nurse. AND, giving breast 'after' solids is only done to "wean" a baby from the breast. BUT AT THIS AGE HE STILL NEEDS BREASTMILK and he still needs to nurse. On demand.
This is per my Pediatrician, and per what I have done with my 2 children who were breastfed.
Baby's and children will "refuse" to eat at times. So what. This is their "learning" about foods and the world. Their eating and food likes will change ALL THE TIME. So be prepared for that. It's normal. ALL kids do this... no matter what age, no matter how old or young. This is just the beginning of it... of a child developing.
Whatever you do, it HAS TO BE "age appropriate." Taking away breastfeeding just because he does not eat the solids that "you" want him to...will just make things worse, and he will not understand that his breastfeeding is being taken away or why. He is JUST A BABY. Their cognitive development is NOT at that level. Your baby is not "challenging"... he is normal. ALL babies, ALL children go through this. Their food likes and dislikes will change all the time. So as a Parent, we must "learn" about what our child thrives with.
All the best,
Susan