Energy density

New research suggests that the fat content of the diet may not be the key to losing weight. Instead the key to weight loss may lie in the energy density of foods. High energy dense foods or dishes contain a large number of calories (from sugar and/or fat) for only a small amount of food, such as chocolate, cakes, biscuits, pies, soft drinks or pizza. However it is also possible to have an overall low energy dense diet on a high fat intake. How is this possible you may ask?

The traditional Mediterranean diet of the 1960's is a good example of a low energy dense diet, despite the high intake of olive oil, because it contains a large number of low energy dense fruits, vegetables and cereals which help to 'dilute' the fat and reduce the number of calories per gram of food. The oil is consumed in vegetable stews, legume soups, salads and
pastas rather than with animal foods and indulgences.

It has been suggested that the traditional Mediterranean diet of the 1960's was very bulky (2kg of plant food consumed daily) with a high intake of fat, mainly derived from olive oil (40% energy as fat or 4 tablespoons of olive oil per day). It has been estimated to have about half the energy density of the typical modern western diet which has less plant food (1kg per day) but paradoxically less fat (30-35% energy as fat). This means that much fewer calories can be consumed on the Mediterranean diet even though a greater volume of food and quantity of fat is eaten.

Due to the fact that total energy consumed is the major factor in weight gain, some fats may be eaten without the accompanying weight gain, but only if they are consumed within a low energy dense diet. In order to achieve a low energy density diet, you do not need to completely alter your eating habits. A food or diet is considered to be energy dense if it has
more than 5kj/gram. The energy density of dark cooking chocolate is 22kj/g. When it is used as an ingredient in Mexican dishes with chicken or vegetables (see above) the concentration of calories or energy density of the dish is more than halved.
Another example: vegetarian pizza has 5kj/g and the 'meat lovers' pizza has 8kj/g.

Studies have been conducted where volunteers were given a low energy dense diet but were given the freedom to snack as they chose. It was discovered that when given lower energy dense foods rather than lower fat foods, the subjects reduced their total energy intake even though they had quite a bit of leeway in regards to snacks. The study concluded that reducing the energy density of the diet may contribute to a significant reduction in energy intake, thus facilitating weight loss.

References

• Rolls, B.J. & Bell, E.A. Intake of fat and carbohydrate: role of energy density. European Journal of Clinical Nutrition, 1999; 53 (Suppl 1): S166-173.
• Jequier, E. Response to and range of acceptable fat intake in adults. European Journal of Clinical Nutrition, 1999; 53 (Suppl 1): S84-S93.
• Calorie density count more than fat. Choice Health Reader, Dec 1999; Vol5, No.10, p9.
• Is the fat message now defunct? Choice Health Reader, Sept-Oct 1999; Vol 5, No7p4.

 

Last Updated: April 5, 2001