I had the same happen with my oldest when he was about that age. Don't give milk until he's eating: meaning give veggies, fruit with his main course (you want him to be able to swallow). I worked with a women at a prek once who wouldn't give a kid milk and she was eating a peanut butter sandwich, she started to gag no kidding. I had to put my finger in her mouth and dig out the food. Kids go through wanting different food and they do change and not always eat as much as they once did. It's called growing spurts the entire first year all he did was grow like a little bean sprout. He's now a toddler he will now grow in little fazes.
Now I'm not so sure only eating 3 times a day will be a good idea. Small amounts of food for breakfast then small simple snack ex:
breakfast: cheerios, strawberries (cut in small pieces) then after he eats since strawberries will wet his mouth later his milk 6 oz
I think you might get some great ideas from the http://www.whattoexpect.com
it's like the book you may have read what to expect when your expecting
they have some great advise on toddlers how much they should be eating. If you little one is still on a bottle for milk you will find it easier to give less milk with a sippy cup.
Also the vitamins you might need to switch from the liquid see what your ped recommends. Rather then be upset pick your battles he's getting older and I found liquids best for infants when the doctor said my little one needs them as for toddlers our ped had us give a chewable.
As far as meat kids got through stages I have a meat lover now not wanting meat and he's 8. You will find stages from now on even as your little one get older like middle school.
