One calorie is equivalent to 4.184 joules. People use large amounts of energy so nutritionists use larger units. The energy in the diet is provided by carbohydrate, protein, fat and alcohol. The amount of energy made available to the body by each of these varies . Fat is the most concentrated source of energy - weight for weight it provides just over twice as much as either protein or carbohydrate.
Alcohol provides almost as much energy as fat.
For some people alcoholic drinks form a large part of their energy intake. This can be harmful to health since a high alcohol consumption is a risk factor for several diseases. BMR is measured when a person is at complete rest, and varies from person to person both within a population group and between different groups. Infants and young children have a proportionately high BMR for their size due to their rapid growth and development. Men usually have a higher BMR than women since they tend to have more muscle.