Marketing claims and the nutritional balance of yogurt - 2011

[PEREZGONZALEZ Jose D (2011). Marketing claims and the nutritional balance of yogurt. Journal of Knowledge Advancement & Integration (ISSN 1177-4576), 2012, pages 184-199.] [Printer friendly]

Marketing claims and the BNI of yogurt

Perezgonzalez assessed the nutritional balance of yogurt in 2011 (see b2,c3,d4,e5,f6,g7,h8,i9). The same data can be analysed further, to ascertain whether marketing claims may (unintentionally) inform about the overall nutritional balance of above products. The claims of greatest interest are nutrition-related claims (such as low-sodium, low-sugar, high-fiber, and low-fat), as well as more generic claims related to health or wellbeing (such as wholegrain, heart-health -eg, the Heart Foundation's "Tick"-, and overall health -eg, Pams' "Pick Me sun" logo).

Illustration 1 collates descriptive information for each relevant claim grouped according to whether such claim is present or absent. Illustration 2 collates inferential information.

Illustration 1: Group size, median & interquartile range per claim group
Claims13 'No' 'Yes'
n median ( IQR ) n median ( IQR )
High fiber 331 90.50 ( 16.66 ) 11 76.93 ( 13.32 )
Low sugar 293 90.50 ( 16.78 ) 49 92.19 ( 30.06 )
Low fat 95 96.76 ( 9.64 ) 247 89.62 ( 16.31 )
Heart health 233 93.59 ( 19.51 ) 109 89.62 ( 12.32 )
(Medians closer to 0.0 indicate greater balance.)

According to these results, it can be concluded that:

  • Yogurts grouped according to 'high fiber' claims show ranked group distances so extreme that, by chance alone, they would occur less than 1 time in 1000. As these yogurts have a lower U (480) than otherwise (3161), it can be inferred that yogurts with a 'high fiber' claim are more balanced nutritionally. This can be easily observed as the median for yogurts with a 'high fiber' claim is lower (76.93) than that of yogurts without such claim (90.50). Such claim alone would identify some 23% of more nutritionally balanced yogurts (see rho values in illustration 3).
  • Yogurts grouped according to 'low sugar' claims show ranked group distances so extreme that, by chance alone, they would only occur about 1 time in 1000. As these yogurts have a lower U (4982) than otherwise (9375), it can be inferred that yogurts with a 'low sugar' claim are more balanced nutritionally. However, this is not so easily observed when looking at the medians, as the median for yogurts with a 'low sugar' claim is higher (92.19) than that for yogurts without such claim (90.5014). Such claim alone would identify some 19% of more nutritionally balanced yogurts.
  • Yogurts grouped according to 'low fat' claims show ranked group distances so extreme that, by chance alone, they would occur less than 1 time in 1000. As these yogurts have a lower U (8355.5) than otherwise (15109.5), it can be inferred that yogurts with a 'low fat' claim are more balanced nutritionally. This can be easily observed as the median for yogurts with a 'low fat' claim is lower (89.62) than that of yogurts without such claim (96.76). Such claim alone would identify some 22% of more nutritionally balanced yogurts.
  • Yogurts grouped according to 'heart health' claims (namely the Heart Foundation's 'Tick' logo) show ranked group distances so extreme that, by chance alone, they would occur less than 1 time in 1000. As these yogurts have a lower U (9374) than otherwise (16023), it can be inferred that yogurts with a 'heart health' claim are more balanced nutritionally. This can be easily observed as the median for yogurts with a 'heart health' claim is lower (89.62) than that of yogurts without such claim (93.59). Such claim alone would identify some 21% of more nutritionally balanced yogurts.
Illustration 2. Mann-Whitney U tests
Claims U 'no' U 'yes' Z ( p )
High fiber 3161.0 480.0 -4.16 ( .000 )
Low fat 15109.5 8355.5 -4.12 ( .000 )
Heart health 16023.0 9374.0 -3.90 ( .000 )
Low sugar 9375.0 4982.0 -3.43 ( .001 )
(Smaller Us indicate greater balance; sig < 0.05, 2-tailed.)

Illustration 3 collates information about three multiple regression models which explore combinations of claims. Overall, when considering all four claims at once (regression model 1, R1, 'enter' procedure), the nutritional balance of 35% of yogurts in the sample can be identified correctly (ie, more claims predict a more balanced product even if not all claims appear on the same product). The second regression model (R2, 'enter' procedure) is able to identify the nutritional balance of about 35% of yogurts in the sample by attending to just three claims: 'high fiber', 'low sugar' and 'low fat', after manually eliminating the less relevant claim from model 1. The third regression model (R3, 'stepwise' procedure) results in a solution similar to that of the second regression model. Thus, each model is able to predict the nutritional balance of yogurts in approximately the same proportion, but the latter models allow to do so by attending to a lesser number of claims, thus being more efficient. Indeed, the 'usability' of each regression model for predicting the nutritional balance of yogurts not in the sample is, approximately, 34%, and 35%, respectively (adjusted Rs).

Illustration 3. Multiple regression models on the ranked BNI
R1 R2 / R3
Claims rho ( p ) β ( p ) β ( p )
High fiber -.225 ( .000 ) -.213 ( .000 ) -.219 ( .000 )
Low fat -.223 ( .000 ) -.161 ( .004 ) -.180 ( .001 )
Heart health -.211 ( .000 ) -.048 ( .445 )
Low sugar -.186 ( .000 ) -.159 ( .007 ) -.176 ( .001 )
R1 = .352 ( .000 )
R2 = .349 ( .000 )
Adj.R1 = .336 Adj.R2 = .349
(Dependent variable = BNI; sig < 0.05, 2-tailed.)

Author

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

Want to know more?

BNI™ journal (2012, issue 1) - Yogurts galore
This issue of the Balanced Nutrition Index™ journal collates all BNI™ nutrition information about the original sample in a single book. You can also access information about individual yogurts on the BNI™ database and aggregated information on Wiki of Science (nutritional balance of food).
Wiki of Science - Nutrition topics
This Wiki of Science page provides access to a variety of nutrition topics, including research related to the one described above.

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