Yogurt, kefir, butter, and hard cheeses (parmesan, etc) have a small percentage of the casein (cow milk protein) that milk does. My daughter had a really hard time with milk, but she loves yogurt, butter, and hard cheeses.
Pffft! Remember, the work of children (and toddlers) is play! As long as he's playing, he's fine.
I don't really "do" Montessori at home, but I like a lot of their ideas. For example, my daughter has only a few toys out at a time, and we try very hard to stay decluttered. I bought some tracing letters and did them a couple of times with her, but I think flashcards are stupid. She actually learned the entire uppercase alphabet from those 2 or 3 times we played...
From Positive Discipline: The First Three Years: From Infant to Toddler--Laying the Foundation for Raising a Capable, Confident Child
Instead of expecting your child to comprehend and "mind" when you say no, follow through with action. You might say "No biting" while gently cupping your hand over the child's mouth and removing him from biting range. You might say "No hitting" while removing him and showing him what he can do. The "no" may be more...
Mother Nature, by Sarah Blaffer Hrdy. Evolutionary biology is a pet interest of mine, but that is an awesome book. She's one of my favorite authors. There is good reason to suppose that those foraging mothers living the most arduous habitats, such as the !Kung San of the Kalahari Desert, gave birth only after very long, four- to five-year intervals. By the time a toddler was three years old, he would have been carried by his mother some four thousand miles....
Sources of fat:
fried food (a la homemade nuggets or fries)
But yea, if he's growing in height, I wouldn't worry too much about it. After 2, they grow very slowly. My daughter, who is disgustingly healthy, only gained 3 lbs between age 2 and 3. She grew 6" though.
Do you have someone who could take #1 out for an hour or two? Perhaps the friends who would otherwise come over and play? (assuming they're healthy). I would want to stay home too.
Montessori from the start
The Toddlers Busy Book
Art for twos and toddlers
Young at Art
The Encyclopedia of Infant and Toddler Activities: Written by Teachers for Teachers
The Complete Resource Book for Preschoolers: An Early Childhood Curriculum With Over...
My daughter is 38 months now, and we've had phases with both of us (husband and I) being chopped liver at different times. No worries - this too shall pass. It helps to have set, defined "Daddy" activities, and set, defined "Mommy" activities. Like, I always give her a bath, but he always reads her to sleep. etc.