But there really is oil when you extracted it from the pork. CMIIW, it's coming from its belly and you can use that to fry as an alternative to the normal oil we use.
when fasting. your body is not ingesting/consuming glucose(sugars) so it burning off your bodies fat for energy.
if you are a thin person. after fasting you need to replenish your fats, because if you get too thin your body at the next fasting will start burning protein(muscles) into energy
if you are obese. then having sugary stuff but in moderation spread out over the day means your body just uses what you consume and doesnt refill your body fats. meaning you can lose weight
just dont go to excess in both cases. meaning if you skip 2 meals dont then binge eat 5 meals after fasting
I've heard stories that a person after fasting ate hard foods such as pork and it has an effect on his body and did no good. I think it depends on the person but that's what I've heard.
So after fasting, eat light to moderate foods that have those nutrients.