Another thing worth knowing is that there are fats that have to jump through some hoops to get digested, and there are fats that get a priority pass straight into available energy.
The first kind you have to have insulin low enough for them to get into your cellular furnaces to be burned for energy. These are most of the fats you eat, and all the fat you store. In the early days your insulin level may not have gotten low enough - so on top of everything else new your body is dealing with … you probably have an energy shortage.
So the trick to know is those second kind of fats are short and medium chained fatty acids.
About 50% of butter is saturated fat, but in every 100g of butter, 11.3g are short and medium chained fatty acids. Butter is 3% butyric acid (4:0), 2% caproic acid (6:0), 1.2% caprylic acid (8:0), 2.5% capric acid (10:0), 2.6% lauric acid (12:0). So 10% of butter you can think of as instant energy.
Coconut oil is even better. in every 100g of coconut oil, 54.5g are short and medium chained fatty acids. 0.5% caproic acid (6:0), 6.8% caprylic acid (8:0), 5.4% capric acid (10:0), 41.8% lauric acid (12:0). So over half of coconut oil you can think of as immediate energy.