Fat. More calories =more heat=more energy.
The most energy rich nutrient is fat. There are two other nutrients that produce energy for the body and they are protein and carbohydrates.
In food, there are three macronutrients that provide energy. They are fat, carbohydrates, and protein. Fat is the nutrient that provides the greatest amount of energy at nine calories per gram. Protein and carbohydrates provide only four calories per gram.
protein protein
Protein and carbohydrates both contain 4 calories per gram and fats contain 9.2 calories per gram. If we are discussing fast energy transfer, simple carbohydrates and fats provide the most available energy
Fat with 9 calories per gram
Fat...
Lipids provide the most amount of energy per gram compared to carbohydrates and proteins. They contain twice as many calories per gram (9 kcal/g) as carbohydrates and proteins (4 kcal/g).
Gram for gram, fats store the most amount of energy in the body, approximately double the amount of energy carbohydrates store.
Fats
Most of Gram+ bacteria and for Gram- ones, Segnilliparus spp.
fats supply the most calories per gram
Carbohydrates provide the most energy in wholemeal bread. When consumed, carbohydrates are broken down into glucose which is the body's main source of energy.