Nutritional balance of chips, crisps & cravers (inferential statistics) - 2012

Table of Contents

Chips, crisps & cravers' BNI (inferences)

foodBNI

Materials and procedure

Data analysis

Generalization potential

Chips, crisps & cravers' BNI (inferences)

This article is a meta-analysis done on nine samples of chips⁷, crisps⁸ and cravers⁹ described individually in other articles (see Perezgonzalez, 2012a¹_d⁴) but here combined for the purpose of such meta-analysis. This article provides inferential information both about the sample of products under research (foodBNI) as well as about a hypothetical diet based on those products (dietBNI).

foodBNI

The population of chips, crisps & cravers appears as nutritionally unbalanced¹⁰ (illustration 1). Indeed, it can be inferred, with a 95% degree of confidence, that the median nutritional balance is located somewhere between BNI 70.40 and BNI 78.76, and the mean somewhere between BNI 69.21 and BNI 75.94.

Illustration 1: Food's nutritional balance
Non-parametric	BNI	WHO	US/CAN	AUS/NZ	UK
Median CI₉₅ lower	70.40	69.77	55.72	58.60	57.00
Median CI₉₅ upper	78.76	79.07	63.54	65.76	64.66
SPR lower	17.34	15.74	17.61	16.81	17.69
SPR upper	25.70	25.03	25.43	23.96	25.35

Parametric	BNI	WHO	US/CAN	AUS/NZ	UK
Mean CI₉₅ lower	69.21	66.12	55.81	59.05	57.31
Mean CI₉₅ upper	75.94	73.60	62.10	64.81	63.48
SD CI₉₅ lower	21.02	23.37	19.66	18.00	19.27
SD CI₉₅ upper	25.76	28.65	24.10	22.06	23.63
(95% confidence interval's lower and upper bounds)

Similar nutritional profiles appear when using other international recommended dietary intakes (RDIs), as well. Indeed, the correlation between indexes is very high (illustration 2). These correlations would occur by chance less than one in 1000, thus it can be inferred that they truly reflect an underlying relationship between international indexes.

Illustration 2: Correlations between international RDIs
r / rho	BNI	WHO	US/CAN	AUS/NZ	UK
BNI CI₉₅ lower		.968	.966	.960	.951
BNI CI₉₅ upper		1.000	1.000	1.000	1.000
WHO CI₉₅ lower	.962		.960	.923	.926
WHO CI₉₅ upper	1.000		1.000	1.000	1.000
US/CAN CI₉₅ lower	.976	.970		.955	.946
US/CAN CI₉₅ upper	1.000	1.000		1.000	1.000
AUS/NZ CI₉₅ lower	.968	.923	.957		.970
AUS/NZ CI₉₅ upper	1.000	1.000	1.000		1.000
UK CI₉₅ lower	.958	.930	.950	.970
UK CI₉₅ upper	1.000	1.000	1.000	1.000
(95% confidence interval's lower and upper bounds)

dietBNI

As part of a hypothetical diet in which all products contributed the same weight of chips, crisps and cravers, the resulting nutritional composition would improve somehow although it would still be unbalanced, with 95% confidence of it ranging somewhere between BNI 62.73 and BNI 71.46. However, differences in international RDIs become more apparent at this level, as this diet would "benefit" more under certain international RDIs than under others. For example, it would be less unbalanced under US', Australia's and UK's RDIs, than under WHO's RDIs.

Illustration 3: Diet's nutritional balance
CI₉₅	Protein	Carbs	Sugar	Fat	Sat.fat	Fiber	Sodium
lower	6.2	59.6	2.7	23.9	7.5	0.5	0.689
upper	6.8	56.9	3.5	26.4	9.2	1.2	0.779
CI₉₅	International RDIs		BNI	WHO	US/CAN	AUS/NZ	UK
lower	(diet)		62.73	62.39	48.31	48.38	47.12
upper	(diet)		71.46	70.66	56.57	56.74	53.71
(Values per 100g; carbs upper and lower bounds are reversed)*

In any case, the most visible differences between the lower and upper bounds of this confidence interval are the levels of fat and sodium that these products provide to the diet (illustrations 4 and 5).

Illustration 4: dietBNI CI₉₅ lower bound

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ideal % = grey cells; actual % = asterisk (*)

Illustration 5: dietBNI CI₉₅ upper bound

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ideal % = grey cells; actual % = asterisk (*)

Methods

Research approach

Exploratory study for mapping the nutritional balance of chips, crisps and cravers in New Zealand.

Design

Quantitative (fixed) in nature, including a mix of a descriptive design and a relational design.

Sample

Stratified sample of 188 chip, crisp and craver products, including generic and proprietary brands, diverse flavors and other relevant categories. The relevant data were collated from previous research after visually ascertaining they shared a similar nutritional profile (see Perezgonzalez, 2012a¹_d⁴). Collating these related samples into one and performing further exploratory analyses will help gain an overall view of the nutritional balance of these foods without being too affected by the small numbers of some of the subsamples.

Variables

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 the 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 and procedure

Relevant data were collected in person by purchasing the food products or by capturing such information from the 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, 2012e⁵).

Data analysis

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Generalization potential

The sample was fairly representative of the population of chips, crisps and cravers in New Zealand. Furthermore, most of the products were either produced locally or imported from Australia. The results of this study may, thus, be generalizable to the following populations (in order of decreasing generalization power):

New Zealand, nationwide.
Australia.
Internationally, if one assumes chip, crisp and craver products to be of approximately similar nutritional composition anywhere.

The results of this study may also be of interest to the following populations:

food researchers
dietitians
food policy makers
consumers

References

1. PEREZGONZALEZ Jose D (2012a). Corn utopia. The Balanced Nutrition Index (ISSN 1177-8849), 2012, issue 6.

2. PEREZGONZALEZ Jose D (2012b). Tasty taytos. The Balanced Nutrition Index (ISSN 1177-8849), 2012, issue 5.

3. PEREZGONZALEZ Jose D (2012c). Crispy crisps. The Balanced Nutrition Index (ISSN 1177-8849), 2012, issue 7.

4. PEREZGONZALEZ Jose D (2012d). Yummy cravers. The Balanced Nutrition Index (ISSN 1177-8849), 2013, issue 1.

5. PEREZGONZALEZ Jose D (2012e). Balanced Nutrition Index™ (BNI™) (2e). Knowledge (ISSN 2324-1624), 2013, pages 38-40.

6. TABACHNICK Barbara G & Linda S FIDELL (2001). Using multivariate statistics (4^th ed). Allyn & Bacon (Boston, USA), 2001.

+++ Notes +++

7. They include both corn chips and potato chips.

8. Snacks made from extruded cereal or potato flour.

9. Savory crackers manufactured so as to compete in the same niche than chips and crisps.

10. When interpreting the BNI as 0 = balanced, 1-9 = slightly unbalanced, 10-19 = moderately unbalanced, 20-29 = highly unbalanced, ≥30 = extremely unbalanced.

11. The lower and upper bounds for carbohydrates are reverse in order to keep the total energy count of the resulting profiles as similar as possible. Carbohydrates were selected for this reversal as they are the nutrient typically set by difference, after estimating proteins and fats.

Want to know more?

WikiofScience - Chips, crisps & cravers (index): This WikiofScience page contains the full list of topics for chips, crisps and cravers, with links to the appropriate files.
WikiofScience - Nutritional balance of chips, crisps and cravers (further knowledge): Two WikiofScience pages provide further introductory and descriptive information about the nutritional balance of chips, crisps and cravers.
WikiofScience - Nutritional balance of foods: This WikiofScience page collates information about several foods on a single page and provides useful links to the appropriate files.