20130122 - Nutritional balance of wheat crisps (descriptive statistics) - 2012

[Data] [<Normal page] [PEREZGONZALEZ Jose D (2012). Nutritional balance of wheat crisps (descriptive statistics). Knowledge (ISSN 2324-1624), 2013, pages 22-25.] [DOI]

Wheat crisps' BNI (description)

Perezgonzalez assessed the nutritional balance of wheat crisps3 in 20122, as part of a research on the nutritional composition of snacks in New Zealand. This article provides descriptive information both about the sample of products under research (foodBNI) as well as about a hypothetical diet based on those products (dietBNI).


The distribution of nutritional balance, as shown in illustration 1, was rather flat, due to the small number of products under research. The median was located at BNI 86.69 and the middle 68% of products ranged between BNI 61 (P16) and BNI 98 (P84). There was a slight negative skewness (mean=81.94, zSkew=-0.84), although, given the size of the sample and the shape of the distribution, this may be of little practical importance.

The distribution of nutritional balance varied slightly according to the particular recommended dietary intakes (RDIs) of reference, although all followed a pattern similar to the one just described. Even so, this group of products appeared slightly less unbalanced under UK's, Australia's and, especially, US's RDIs than under WHO's RDIs.

Illustration 1: Food's nutritional balance distribution
International RDIs
≥40 1
≥50 1 2 1 2 2
≥60 1 1
≥70 1 1 1 2
≥80 2 1 2 2 1
≥90 2 2 1 1
Median 86.69 83.06 72.49 79.04 78.04
SPR 18.44 22.37 18.79 19.16 18.36
P16 60.76 52.90 46.40 53.86 53.46
P84 97.63 97.63 83.98 92.17 90.17
RSkew -7.50 -7.80 -7.30 -6.03 -6.23
Mean 81.94 78.08 68.38 75.26 73.71
StDev 14.98 18.55 15.35 15.75 15.52
zSkew -0.84 -0.68 -0.82 -0.64 -0.66
zKurt -0.66 -0.87 -0.61 -0.84 -0.98
Unstandardized small medium large ( Avg.StDev )
effect size4 3 8 13 ( 16 )

Correlations between indexes were high, thus supporting the idea of a common pattern in the distribution of nutritional balance across international indexes for this particular group of products.

Illustration 2: Correlations (Pearson and Spearman)
BNI .943 .943 .943 .943
WHO .991 1.000 1.000 1.000
US/CAN .988 .997 1.000 1.000
AUS/NZ .991 1.000 .997 1.000
UK .992 .997 .988 .997


As part of a hypothetical diet where all products contributed the same weight of crisps, the resulting nutritional unbalance would remain practically the same for most indexes, although WHO's index improves moderately and US's index improves slightly in comparison to the average food product (when attending to the unstandardized effect size for this group).

Illustration 3: Diet's nutritional balance
Protein Carbs Sugar Fat Sat.fat Fiber Sodium
9.5 65.6 3.7 15.6 5.7 0.0 1.352
(diet) 80.34 71.29 64.80 74.80 72.80
(Values per 100g)


Research approach

Exploratory study for mapping the nutritional balance of wheat crisps3 in New Zealand.


A sample of 6 wheat crisp products, including diverse brands and flavors, and other relevant categories (see Perezgonzalez, 20122). Notwithstanding this, the actual products were collected in a convenient manner from four major national supermarket chains. The final sample covered most of the population of wheat crisp products available at those supermarkets.


Variables of interest for this research were the following:

  • Weight contribution of seven nutrients (protein, carbohydrate, sugar, fat, saturated fat, fiber and sodium) to 100g of a food product.
  • The Balanced Nutrition Index (BNI) of each food product, as calculated from above variables.
  • Aggregated information for the sample of products (foodBNI).
  • Aggregated information about the individual nutrients for the simulation of hypothetical diets (dietBNI).

Materials & analysis

Relevant data were collated after purchasing the food products or by capturing such information from producers' websites if this information was available and was deemed reliable. The data were then assessed using the Balanced Nutrition Index™ (BNI™) technology (see Perezgonzalez, 20111).

SPSS-v18 was used for the computation of variables, including BNI and international indexes, and for descriptive statistical analyses.

Generalization potential

Although the research sample captured a large proportion of the wheat crisp products available at the time, the resulting sample is still too small as for inferring anything beyond the group of products here described. It is recommended to collate the data from this group with that of related groups of products if inferential analyses are intended.

1. PEREZGONZALEZ Jose D (2011). Balanced Nutrition Index™ (BNI™). Journal of Knowledge Advancement & Integration (ISSN 1177-4576), 2011, pages 20-21.
2. PEREZGONZALEZ Jose D (2012). Crispy crisps. The Balanced Nutrition Index (ISSN 1177-8849), 2012, issue 7.
+++ Notes +++
3. Snacks made from extruded wheat.
4. This is the estimated unstandardized effect size for group differences (Cohen's d and Glass's Δ) given an average standard deviation and following Cohen's d effect size interpretation. It can be used to ascertain the relative importance of descriptive data without the need to perform inferential tests.

Want to know more?

BNI analysis of individual mixed cereal crisp products
You can access either the BNI™ database or the 'BNI™ journal (2012, issue 7) - Crispy crisps' for individual nutrition analyses of each food product in the sample.
Wiki of Science - Nutritional balance of foods
This Wiki of Science page collates information about several foods on a single page and provides useful links to the appropriate files.
Wiki of Science - Nutritional balance of wheat crisps (introduction)
This Wiki of Science page provides an introductory descriptive analysis of the nutritional balance of wheat crisps.


Jose D PEREZGONZALEZ (2012). Massey University, Turitea Campus, Private Bag 11-222, Palmerston North 4442, New Zealand. (JDPerezgonzalezJDPerezgonzalez).


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