I have never been a calorie counter until my son at 18 months old dropped to the bottom of the growth chart in weight. My daughter did the same thing at the same age. Needless to say I began watching calories a lot but in the opposite direction than most might be. I knew that a lot of their stature was attributed to genetics and when we went to the Nutritionist and they did a calorie count they were actually taking in more then they should have needed to grow correctly. So we worked and worked on adding as much good fat to the diet as possible and making meal time as much fun as we can.
One thing that shocked me a bit during this process is that it is actually some what difficult to find high calorie foods that do not have a ton of bad fats or sugar in them. For example most yogurt aimed towards children is low-fat and has tons of sugar in it. Children actually really need good healthly fat, it is very important to their proper growth (actually all of us do it helps brain functioning, skin health, and mood). Luckily I tend to make most of my own food anyway so I usually would just buy a whole fat item and do the rest myself. Whole fat plain yogurt with honey and frozen berries works like a charm.
Another way that I went about getting my little ones to eat more calories was to try and find new ways to eat the same old foods. Eating time is also great because there are many other developmental tasks that take place during this time. This particular recipe uses fine motor skills, gross motor skills, social interaction, imaginative play, learning about the five senses, and confidence building because this is something they can create and eat on their own (with the exception of cutting the apple).
The Apple Pizza Snack
One apple sliced into thin rounds (see picture below)
Nut butter or nut butter substitute (yogurt, sunflower seed butter)
Shredded coconut (we like unsweetened)
Any other "toppings"
Set up for you kid to spread the sauce (nut butter) and add the toppings (shredded coconut & dried fruit)