The Balanced Nutrition Index™
The Balanced Nutrition Index™ (BNI™)7 is a technological application (a formula) for assessing the nutritional balance of foods, recipes and diets. It uses dietary recommended intakes (RDIs) as the base for analysing the composition of foods and assessing their nutritional balance. Thus, it is able to index foods and diets according to such balance.
The BNI's underlying principle is quite simple: it subtracts actual macronutrients' contribution to foods from 'ideal' macronutrients' contribution, adds the differences and, in so doing, compiles a unique figure that allows for indexing a given food product according to its degree of nutritional unbalance. (See, for example, Perezgonzalez, 2007a1.)
Interpreting the BNI™
The BNI™ code
Oat breakfast cereal Corn chips Typical chocolate bar BNI™ 8.70c BNI™ 49.44f BNI™ 126.94-fb (Source: The Balanced Nutrition Index™ database)
The BNI™ appears as a numerical figure indicating relative degree of nutritional unbalance, and a trailing letter code indicating the main nutritional bias in the food.
- Balanced foods will show an index of 'zero' and no trailing letter code (ie, BNI™ 0.0).
- Unbalanced foods will show an index greater than 'zero' whereby the greater the numerical index the more unbalance the food is.
- The trailing letter, whenever used, identifies the most unbalanced macronutrient in the food. The possible trailing letters are the following:
|p||excess of protein|
|-p||deficiency in protein|
|c||excess of carbohydrate|
|-c||deficiency in carbohydrate|
|s||excess of sugar|
|f||excess of fat|
|-f||deficiency in fat|
|sf||excess of saturated fat|
|fb||excess of fiber|
|-fb||deficiency in fiber|
|na||excess of sodium|
The BNI™ scale (2012)
The BNI™ is sensitive enough as for allowing 'indexing' food products according to their nutritional balance8. But it provides little guidance regarding how to interpret the resulting scale. Since October 2012, the following 'qualitative' interpretation is used9:
|> 0||slightly unbalanced|
|≥ 10||moderately unbalanced|
|≥ 20||highly unbalanced|
|≥ 30||extremely unbalanced|
Types of BNI™
There are two types of BNI™, which occur as a consequence of using the BNI™ in statistical analyses: the foodBNI™ and the dietBNI™. A third type comes from using different sets of RDIs.
- The foodBNI™ is the BNI of finalised foods and ingredients. For example, each potato chip product in a supermarket will have its own BNI, which is particular to such brand and make. Such foodBNI can be used in statistical analyses, and will provide information about the group of foods being analysed (eg, about the average nutritional balance of all potato chips, irrespective of brand and make).
- The dietBNI™ is the BNI of meals (which combine different ingredients at once) and of diets (which combine diverse foods and meals over time). The dietBNI™ results from the combination of different foods in variable proportions and, thus, cannot be predicted from the particular BNI of foods (eg, eating potato chips from different brands and flavors, something not uncommon in a party, may result in a more balanced 'meal' than the average foodBNI of the potato chip products would suggest). Therefore, the calculation of both foodBNI and dietBNI is similar; the only difference between both indexes is that the former is more appropriate when describing group of products or individual foods, while the latter is more appropriate for assessing the combination of several foods into a meal or diet (for example, for simulation purposes).
- Related nutrition indexes are a third type of BNI™, which are obtained using the corresponding RDIs and are interpretable in the same manner than the BNI™. The concept of BNI™ is, however, avoided for these indexes so as to prevent confusion.
Properties of the BNI™
- The BNI™, as its name says, 'works' within the concept of balanced nutrition, rather than alternative concepts such as balanced diets, varied diets, healthy diets or healthy lifestyles (Perezgonzalez, 2011a5). It is, if you wish, a 'mathematical' approach to food indexing, not to dieting.
- The main "theoretical" background for the index are recommended dietary intakes (RDIs). In order to enhance standardization, however, the index works with a single set of RDIs, which is an average result obtained from other modern Western RDIs (Perezgonzalez, 2011b6). However, by changing the RDIs, it may be used for analyzing food products according to particular national standards.
- The index works with macronutrients only, although, given its social importance, it also includes sodium. Most of this nutritional information is readily available on nutrition labels, or commonly reported in food databases (such as USDA's). Protein, carbohydrate, sugars, fat, saturated fat, fiber and sodium are the nutrients that the index uses.
- The index works by calculating the percentage contribution of each nutrient to 100 grams of food. It then compares this against the percentage contribution expected from an 'ideal' balanced food ('ideal' meaning according to RDIs). Any macronutrient differences in excess or deficiency from this 'ideal' contribution is added up (as natural numbers) into a single figure, representing the accumulated macronutrient unbalance. Adequately balanced foods will show an index of 'zero' (BNI™ 0.0), while the greater the numerical index the more unbalance the food is (eg, a typical chocolate bar is around BNI™ 124.00).
- The numerical figure is further qualified with signs and letters, which identify the most important macronutrient. These signs and letters not only indicate the food's main nutritional bias, but also helps differentiate between foods with similar numerical results. The possible qualifications are the following: 'p', excess of protein, '-p' deficiency in protein, 'c' excess of carbohydrate, '-c' deficiency in carbohydrate, 's' excess of sugars, 'f' excess of fat, '-f' deficiency in fat, 'sf' excess of saturated fat, 'fb' excess of fiber, '-fb' deficiency in fiber, and 'na' excess of sodium.
- Therefore, the BNI™ appears as a numerical figure indicating relative degree of nutritional unbalance, and a letter code indicating the main nutritional bias in the food. This index is sensible enough as for allowing 'indexing' food products according to their nutritional balance8.
- The BNI™ was first formulated in 2007 and used a 'mid-point' calculation, resulting in larger numerical indexes and a subjective assessment of those indexes closer to 'zero' as 'balanced' (eg, Perezgonzalez, 2007a1, 2007b2). The formula was changed to a 'range' calculation in 2008. With this advanced formulation, only macronutrient contributions which fall outside an RDI range count towards unbalance, making the index more accurate, as it also eliminates any subjective assessments (ie, a balanced food is that with BNI™ 0.0) (See, for example, Perezgonzalez, 2008a3, 2008b4.)
Did you understand?
Want to know more?
- Balanced nutrition
- This Wiki of Science page deals with the meaning of balanced nutrition and how to differentiate it from related concepts, such as a balanced diet, a varied diet and a healthy diet.
- The Balanced Nutrition Index™
- You can find further information related to the index in the Balanced Nutrition Index™ database or the Balanced Nutrition Index™ journal.
Jose D PEREZGONZALEZ (2012). Massey University, Turitea Campus, Private Bag 11-222, Palmerston North 4442, New Zealand. (JDPerezgonzalez).