Fats are quite difficult for the body to break down. But carbs, especially sugars, are really easy to digest. If one eats a lot of fat, it may actually make its way out unchanged.*
*I'm not a nutritionist, I just drank 250ml of olive oil after loosing a bet.
Probably springtails. They are not harmful, but may indicate overwatering (unless the plant needs constantly wet soil). They eat fungi and float in water, which is cool.