Answer:
This energy comes from fats, specifically lipids.
Step-by-step explanation:
Lipids are fat molecules that, in the organism of living beings, perform a series of biological functions, mainly the long-term storage of energy.
One of its characteristics is that they are easily stored by the body, but they are difficult to consume. This explains why foods rich in lipids are usually the ones that contribute the most to those unwanted fats!
In fact, when ingested in excess, they are stored in adipose tissue. The organism normally only starts to consume these molecules when there is a deprivation of other energy sources.