The energy % scheme provides a measure of nutrition that is linked to real-world meal structures and food combinations.
The energy % scheme is based on Government nutrition guidelines (Dietary Reference Values http://www.nutrition.org.uk/home.asp?siteId=43§ionId=414&parentSection=320&which=1) and ‘food structuralism’ http://www.uwm.edu/~wash/food.htm
Energy percentages can be used to assess the energy-nutrient profile of a meal or snack and demonstrate the changes in energy-nutrient profile that accompany different food combinations.
The concept of energy percentages was first described in the publication of Dietary Reference Values in 1991. Energy percentages provide a way to think about nutrient intake that can be related to calories, one of the best known, and used by consumers, elements of dietary labelling. In DRV, target percentages are provided for the macronutrients as follows:
Fat max 35%, sat fat max 10%
Carbs min 50%, sugar max 10%
Protein min 15%
The energy percentage is obtained through the following calculation (for each macronutrient – fat, carb and protein):
Cals per gram (protein and carb = 4; fat = 9) x gram weight / Total Cals x 100
Energy percentages can be used to compare individual foods. This approach can then be extended to the comparison of processed and branded food products, allowing for recognition of healthier products. Currently all processed food is considered ‘bad’ but in fact products on the market vary widely in their fat, protein and nutrient content between products (and between different brands of the same product):
|
|
DRV | Pasty | Sausage | Pizza | Vegeburger |
| Sat fat | 10 | 19 | 28 | 16 | 9 |
| Non-sat fat | 25 | 38 | 47 | 20 | 22 |
| Sugars | 10 | 1 | 3 | 3 | 9 |
| Non-sugar carb | 40 | 34 | 6 | 40 | 46 |
| Protein | 15 | 8 | 16 | 21 | 14 |
But foods are rarely eaten on their own, and this is where the second element of the e% scheme comes in – the theory of food structuralism, originated by Levi-Strauss and proliferated by Mary Douglas. Food structuralism depicts diets as a series of different cultural rules for combining foods. Rather than focusing on the consumption of individual foods, food structuralism examines the ways foods are combined into dishes, for which occasions, and to be eaten where and with whom – the ‘food event’.
Energy percentages are especially useful for assessing total energy profile at a ‘food event’ (meal or snack). What is particulalry striking about this approach is that by changing discrete food items in a food event, the overall energy profile of the whole food event can change dramatically. When I taught nutrition, this was an exercise that thoroughly engaged students and very often they discovered that the simple addition of an apple could shift the balance of energy intake to a more positive profile. In this way, energy percentages can be used to demonstrate changes in nutritional profile related to meal structures.
|
|
DRV | a | b | c | d | e |
| Fat | 35 | 53 | 42 | 52 | 6 | 7 |
| Carb | 50 | 31 | 40 | 32 | 73 | 72 |
| Protein | 15 | 16 | 18 | 16 | 21 | 21 |
a = Sausage + slice of bread;
b = Sausage, bread + beans;
c = Sausage, bread + chunk of fresh pepper;
d = Beans + bread;
e = Beans, bread + pepper
