Hi J-
Although our K. can at times appear fussy about what they'll eat/drink, there are times that it's important to honor their choices. You concern points to a large myth- that myth is that our children need to drink cow's milk in order to be healthy/get enough calcium. Let me explain: Breast milk is the perfect food for our children, as most of us know. Breast milk also contains the highest amount of lactose of any other food. In the first year of life, our bodies make lactase, the enzyme necessary to break down lactose. As we approach a year old, a common time to be weaned from breast milk, we no longer make lactase. This may be why your son no longer wants cow's milk, which is high in lactose. His body may very likely be having a difficult time breaking it down.
As humans, we are the only mammals on the planet that consume another mammal's milk. It may not sound like a bad idea, however, we simply don't have the physiology to be able to handle it.
COW'S MILK IS THE #1 CAUSE OF FOOD ALLERGIES WHICH SHOW UP AS TUMMY ACHES, LOOSE STOOL, ECZEMA, LOWERED IMMUNE SYSTEMS AND EAR INFECTIONS.
I hear and respect your concern for your child getting the proper nutrients he needs.
As a physician who treats children holistically, I encourage you to explore "non-dairy sources of calcium".
And in regards to him getting enough fat- yes, you're right. He does need fat for his developing nervous system. The fat he specially needs are essential fatty acids, also known as omega 3. Nordic Naturals makes a great strawberry chewable.
Good luck and if you still have questions, I would encourage you to contact a local licensed Naturopathic Doctor in your area.
Dr. T. Fleck
Santa Cruz, CA
p.s. Any dairy products that you do feed your child should be Organic. Non-organic sources contain hormones & other chemicals that can be damaging to a developing system.
p.s.s. Soy is another common allergen in children. Try rice, almond, oat or hemp milk.