Energy Density and Weight Loss

Energy Density refers to the amount of Energy or kilojoules per 100 grams of food intake. Foods of equal size can have 2, 5 or 10 times the energy content of other foods. Energy Density is usually measured per 100 grams of food content.

What Determines the Energy Density of Food?

The Energy content per 100 grams of a food is determined by the amount of Carbohydrates, Fats, Proteins and Alcohol in that food. Foods containing high amounts of any of these energy sources will contain high energy densities. Fats and Alcohol have the highest energy content per gram, as a result foods high in either will contain the largest energy densities.  

Foods containing high water or fibre contents will contain lower energy densities. This is because the water and fibre content makes up the majority of the foods size, resulting in lower concentrations of fats, proteins and carbohydrates.

Energy Density Classifications

Knowing the energy density of the foods you consume is important. Studies show food intake is affected by the weight or size of the food. When two identical looking meals are provided to two different groups of people, one meal containing low energy density and the other high energy density what is found is that both groups eat similar amounts of food. What this means is those consuming the low energy density foods eat less kilojoules or energy by the end of the meal. This in the long term will have the effect of reducing body fat (1,2).

Learning which foods contain higher energy contents is a simple educational process that will produce weight loss. Changing your diet to include lower energy density foods is a sustainable way to create weight maintenance.

Foods containing a high content of water have lower energy densities. Similarly higher fibre foods have lower energy densities. The fibre content particularly soluble fibre, slows the absorption of food, resulting in decreased hunger.

A lot of appetite and food intake is psychological and as social beings people tend eat food socially and also by site. Eating larger bulkier foods can lower total energy consumption resulting in weight loss. The below table highlights the importance of energy density in relation to total daily intake. The table shows the how much of each food must be eaten to provide a 2500kj meal. Notice the number sandwhiches compared to Big Mac burgurs required to produce a meal.

How to Snack Correctly

Snack choice is extremely important for weight loss. Snacks help to stabilize blood glucose between meals and provide satiety. When snacking choose low energy density foods. Notice one 62.5g mars bar provides approximately the same energy as 3 pears or 12 small carrots. Eating one pear and one carrot as snack would see you consuming around half the kilojoule or energy intake of the mars bar.

Learning the Energy Density of Food

Finding out the energy density of your food is very easy. It can be done by reading the nutritional label of the product. Look at the energy content, (kilojoule value) per 100grams of the food

For foods which do not have lables check the website  http://www.nal.usda.gov/fnic/foodcomp/search/ This database contains a comprehensive list of foods along with their energy contents, vitamins, fibre levels and much more. Be sure to select a 100 gram portion of the food when searching the database. Also view