Do "reduced fat" chocolate chip cookies have less chocolate per serving (48 g) than "regular" chocolate chip cookies? Two comparable brands ofcookies [Keebler Chips Deluxe and Nabisco Chips Ahoy], each offering a "regular" and "reduced fat" variety of chocolate chip cookie, were tested. Chocolate was extracted and weighed from ten samples of each type and brand of cookie. Descriptive techniques as well as t-tests and a two-way ANOVA indicate that, on average, "reduced fat" cookies contain significantly fewer grams of chocolate, per serving, than do their "regular" counterparts, regardless of the brand chosen.
Do cookie companies reduce the amount of fat in chocolate chip cookies by using less chocolate chips in the "reduced fat"cookies? Since chocolate contains a high proportion of fat, cookie manufacturers may use the reduction of chocolate in cookies as one way to significantly reduce the overall fat content in cookies. Two comparable and competing cookie brands, Keebler Chips Deluxe and Nabisco Chips Ahoy, were examined to determine the number of grams of chocolate in one 48 g serving of cookies.
An experiment was designed to answer the following questions:
The following data assumptions were made:
After defining the questions, three local grocery stores were surveyed to determine the number of brands of chocolate chip cookies which have both regular and "reduced fat" cookies. Four (4) brands with comparable products in both "fat types" were identified: Keebler Deluxe Chips; Nabisco Chips Ahoy; Pepperidge Farm; and Entenmann's. In addition, Nabisco Mini Chips Ahoy and SnackWell's Reduced Fat Chocolate Chip Cookies were determined to be comparable in serving size, weight and product ingredients. One bag (or box) of each cookie brand and type was purchased. Given time constraints, however, this study focused on the two most similar brands, Keebler Chips Deluxe and Nabisco Chips Ahoy.
Ten 48 g cookie servings from each brand and type were pulverized by hand to extract all chocolate content. Using a kitchen scale, the chocolate content was weighed and recorded.
The resulting data was explored graphically using several descriptive analysis techniques available through Minitab. Two sample t-tests, with pooled variances, were employed to answer the questions regarding the differences in the mean number of grams of choclate content in "regular" and "reduced fat" cookies "within each brand" and "regardless of brand or "fat type" (i.e. questions 1 through 3 above). A Two-Way ANOVA was used to investigate the effects of brand and "fat type" on the mean number of grams of chocolate, per serving, in the chocolate chip cookies (i.e. question 4 above).
The following notation is used on the data plots and Minitab output.
Symbol Meaning K Keebler Chips Deluxe Brand CA Nabisco Chips Ahoy Brand Low Reduced Fat type of cookie Reg Regular type of cookie
Descriptive Statistics included:
A visual examination of four character dotplots, one for each sample set (brand-type combination), [Fig. **] and the four related boxplots [Fig **] revealed that the two "reduced fat" data sets were, on average, lower in chocolate chip weight content than the two "regular" sets. Examination of means and variances and related graphs [Fig **] seemed to reasonably support the assumptions of equal variances and normal populations.
Two-Sample t-tests and confidence intervals were computed (and graphed) for the following comparisons:
(1A) H0: MU[KLow] => MU[KReg] vs. H1: MU[KLow] < MU[KReg]
Reject the null hypothesis (t=-4.90; p=0.0001). On average, Keebler "reduced fat" cookies contain significantly fewer grams of chocolate than Keebler "regular" cookies.
(1B) H0: MU[CALow] => MU[CAReg] vs. H1: MU[CALow] < MU[CAReg]
Reject the null hypothesis (t=-4.71; p=0.0001). On average, Chips Ahoy "reduced fat" cookies contain significantly fewer grams of chocolate than Chips Ahoy "regular" cookies.
Reject the null hypothesis (t=-6.18; p=0.0000). On average, "reduced fat" cookies contain significantly fewer grams of chocolate than "regular" cookies, regardless of brand (Keebler or Chips Ahoy).
Fail to Reject the null hypothesis (t=0.72; p=0.47). On average, Keebler chocolate chip cookies do not contain significantly different amounts of chocolate per 48 g serving than Chips Ahoy.
Statistics and Graphs included:
The Two-Way ANOVA produced an F-value of 1.14 (p=0.293). Fail to reject the null hypothesis. On average, there is no significant interaction between Brand and "Fat Type" on mean number of grams of chocolate per serving (48 g) in chocolate chip cookies.
The Two-Way ANOVA produced an F-value of 1.14 (p=0.293). Fail to reject the null hypothesis. On average, there is no significant difference in mean number of grams of chocolate per serving (48 g) between the two brands.
The Two-Way ANOVA produced an F-value of 45.61 (p=0.0000). Reject the null hypothesis. On average, there is a significant difference in mean number of grams of chocolate per serving (48 g) between "reduced fat" and "regular" cookies.
The appropriately scattered pattern in the related "Residual vs. Fits" plot supported the hypothesis that the two-way ANOVA model was appropriate.
A plot of the means shows approximately parallel lines (no crossover effect); hence the main effects of brand and "fat type" on number of grams of chocolate per serving (48 g) can be interpreted independently since there is no significant interaction between brands and "fat type."
Based on the results of this study, on average, "reduced fat" chocolate chip cookies do contain fewer grams of chocolate per serving (48 g) than "regular" chocolate chip cookies.
It appears that one method used by cookie manufacturers to reduce fat content in chocolate chip cookies is to reduce the amount of chocolate per serving. Based on observations made during the chocolate extraction process, another possible source of difference in fat content may be attributable to differences in the amount of fat in the cookie dough.
This study could be improved by employing a random sampling technique, using a more accurate scale, and a more climate controlled storage and chocolate extraction environment. Recommendations for extentions of this study as well as future studies include:
Questions for future investigation include:
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