Few more tidbits:
Energy is 'the capacity to do work.'
This definition is very specific. It is has nothing to do with some colloquial uses such as 'feeling' energetic or a person having 'positive' energy.
'Energy' drinks often contain little to no food energy but are instead stimulants. Stimulants may make stored energy more available but are not a source of energy themselves.
In the context of food, we use the 'Calorie' measurement for food energy. Spelled with a capital 'c" denotes a kilocalorie (amount of energy required to raise the temp of one kilogram of water by one kelvin/degree celsius). This is an older unit of measurement; the modern unit is the Joule. One kcal is equal to 4.19 kilojoule.
A pound of bodyfat contains about 3,500 Calories (kcal). A pound of pure fat contains 4,086 Calories. The difference is that bodyfat also contains some water.
Energy cannot be created or destroyed - only converted from one form to another at no more than 100% efficiency. Energy is also conserved. This is why you cannot lose weight by eating more calories or vice versa(all else being equal).
The human body can turn protein into carbs (glucose) and carbs into fat but cannot do the same in reverse. So protein is a more versatile macro.
Carbs themselves do not make people fat. It is the calories that carbs contain that contribute to excess energy intake that cause it.
Complex vs simple carbs is an outdated classification. Use GI instead.
Test on Monday. ?