PROTIENS
Fats (lipids) have the most highly concentrated energy of all organic compounds, providing 9 calories per gram when metabolized. This is more than double the energy content of carbohydrates and proteins, which provide 4 calories per gram when metabolized.
Fats provide approximately 9 calories (37.7 kJ) of energy per gram.
Ash itself contains no calories, as it is primarily composed of inorganic minerals left after the combustion of organic material. Since it does not provide energy, one gram of ash contributes zero calories to the diet.
Carbohydrates and proteins provide 4 calories per gram, while fats provide 9 calories per gram. Alcohol provides 7 calories per gram.
Lipids, specifically triglycerides, provide long-term energy storage in the form of fat in animals and oils in plants. These molecules are highly efficient at storing energy because they contain more energy per gram than carbohydrates or proteins.
carbohydrate
Fats have the most energy gram for gram. I think that lard (sometimes called shortening) is the highest calorie out of all fats (but it's not much different to all other fats really).
Hydrocarbons like gasoline or diesel generally provide the most energy when one gram is burnt, as they have high energy densities. Other fuels like hydrogen gas or methane can also provide a lot of energy per gram when burned.
The primary nutrients that yield energy are carbohydrates, proteins, and fats. Carbohydrates provide approximately 4 calories per gram, while proteins also yield about 4 calories per gram. Fats are the most energy-dense, delivering around 9 calories per gram. Alcohol can also provide energy, yielding about 7 calories per gram.
fats
One gram of fat equals 9 calories.
1 gram of fat provides 9 kcals......and 1 gram of protein/carbs provide 4 kcals...