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ABSTRACT This study investigated the effect on fat and
energy intakes of fat-free potato chips made with olestra com-
pared with regular potato chips. Ninety-five participants (unre-
strained and restrained males and females) were tested in 2 con-
ditions. In the information condition, participants were given
nutrition information about the chips and were aware that the
chips differed in fat and energy contents. In the no-information
condition, participants were not aware of the differences. In both
conditions, participants ate either regular or fat-free potato chips
ad libitum for an afternoon snack in a crossover design in two
10-d periods. To assess 24-h intake, participants completed food
diaries twice in each 10-d period. The results showed that all
groups significantly reduced their fat and energy intakes in the
snack when eating the fat-free chips compared with the regular
chips (P< 0.0001). Also, potato chip intake did not differ across
time for either type of chip. Over 24 h all participants had lower
fat intakes (P< 0.05) when eating the fat-free potato chips com-
pared with the regular chips, but 24-h energy intake was not
significantly different between groups. When information was
provided, restrained participants ate more of the fat-free chips
than the regular chips; however, this increase did not negate the
reductions in fat and energy associated with eating the fat-free
chips. This study showed that substituting fat-free (olestra-
containing) potato chips for regular-fat chips can help reduce fat
and energy intakes in short-term (within meal) situations and
reduce fat intake over 24 h. Am J Clin Nutr 1998;68:282–90.
KEY WORDS Sucrose polyester, olestra, fat intake, energy
intake, snacking
INTRODUCTION
Health organizations such as the National Research Council
(1) and the US Department of Health and Human Services (2)
recommend that no more than 30% of total energy be derived
from dietary fat. Diets high in fat have been associated with sev-
eral negative health outcomes such as cardiovascular disease,
type 2 diabetes, and some cancers. High-fat savory snacks have
been found to be a significant source of fat intake for Americans
(3). Two studies found that food consumed between meals is a
major source of energy intake in obese people (4, 5). Also,
because the foods craved most often are those that are energy
dense, such as chocolates, sweets, and high-fat, high-sodium
snacks such as potato chips (6, 7), it may be difficult for some
people to curtail their intake of snacks. It follows that the avail-
ability of highly palatable, fat-free alternatives to traditional
savory snacks may affect dietary fat intake.
Recently, olestra, a sucrose polyester, was approved by the US
Food and Drug Administration for use in savory snack products.
Olestra is a lipid that cannot be absorbed by the gut and con-
tributes neither fat nor energy to the diet. With the use of olestra,
the fat content of fried foods can be modified, opening up new
possibilities for reduced-fat snack foods. The effect on daily fat
intake of using olestra to modify the fat content of savory snack
foods is potentially large. Potato chips fried in olestra have no fat
and half of the energy content of regular snack foods while
retaining the sensory qualities of crunchiness and oiliness and
the flavor-carrying properties associated with frying in fat.
A recent survey indicated that 137 million Americans (75% of
adults) currently regularly consume reduced-fat foods with the
expectation that these foods will aid in reducing their fat and
energy intakes (8). Also, 93% of dieters in that survey stated that
they use reduced-fat and fat-free foods to help comply with
weight-reduction diets (8). However, despite this widespread use
of reduced-fat foods and the assumption that the use of these
products will be helpful in controlling body weight, there is lit-
tle information concerning the effect that reduced-fat and
reduced-energy foods will have on food intake.
There are some important issues regarding the actual usage of
these products that have not been investigated in a laboratory set-
ting. One such issue is whether these products will lead to a
reduction in fat and energy intakes, and, if so, whether such
reductions will be short-term (over the course of the snack or
meal) or whether they will persist over the course of a day.
Another important issue is whether people with different person-
al characteristics, such as sex and body weight, will respond to
fat-free products differently. In addition, it is important to con-
Effect of fat-free potato chips with and without nutrition labels on
fat and energy intakes
1–3
Debra L Miller, Victoria H Castellanos, David J Shide, John C Peters, and Barbara J Rolls
1
From The Pennsylvania State University, Nutrition Department, Univer-
sity Park, and the Procter & Gamble Company, Cincinnati.
2
Supported by the National Institute of Diabetes and Digestive and Kid-
ney Diseases (grants DK-39177 and DK-08926). Potato chips were con-
tributed by the Procter & Gamble Company.
3
Address reprint requests to BJ Rolls, 226 Henderson Building, Depart-
ment of Nutrition, The Pennsylvania State University, University Park, PA
16802-6501. E-mail: dbmiller@welchlink.welch.jhu.edu.
Received July 2, 1997.
Accepted February 9, 1998.
Am J Clin Nutr 1998;68:282–90. Printed in USA. © 1998 American Society for Clinical Nutrition
282
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sider the level of dietary restraint of participants when they consume
reduced-fat and reduced-energy foods. Dietary restraint refers to the
degree to which individuals restrain or restrict their food intake
because of concern about body weight. Alexander and Tepper (9)
found that young adult women and young adults with high dietary
restraint were more likely to use reduced-fat and reduced-energy
foods for weight control. Thus, it is likely that women and
restrained individuals may eat more of the fat-free potato chips than
the regular potato chips because a fat-free snack food may not rep-
resent a violation of self-imposed dietary restrictions.
Regulation of food intake involves a complex interplay of both
physiologic and cognitive mechanisms. One way that individuals
learn about the nutrient composition of foods is through package
labels. Although there is little information available regarding how
consumers use reduced-fat foods, there is even less information
about the effects of labeling on eating behavior. Recent research
showed that perceptions of the energy and nutrient composition of
foods can affect food intake. For example, Shide and Rolls (10) fed
women equienergetic preloads of yogurt labeled low fat and high
fat. They found that women ate more in a self-selected lunch after
eating the yogurt labeled low fat than after eating the yogurt labeled
high fat. Other studies found similar results, reporting that informa-
tion about foods affects food intake (11–15) and feelings of hunger
and fullness (14, 16, 17), but some studies found no such effects of
information (18, 19). One study looked at the effects of providing
information about foods manipulated with sucrose polyester and
reported no effects of this information on food intake in female par-
ticipants and a small effect in males, with male participants com-
pensating more for reductions in fat and energy, that is, eating addi-
tional energy- and fat-bearing foods when they knew the foods were
reduced in fat (20).
Information about the fat and energy contents of a product may
affect restrained eaters differently from those not restrained. Few
studies have investigated the effects of both restrained eating and
information about reduced-fat and reduced-energy products. Shide
and Rolls (10) found no differences related to restraint status in
intake after a high- or low-fat preload, and Aaron et al (21) found no
differences of restraint status on sensory evaluations of reduced-
fat spreads. However, most of these studies (10–19) did not
investigate ad libitum consumption of the actual reduced-fat and
reduced-energy products. Thus, it is unclear how information
about fat and energy contents affects food intake in individuals
with high dietary restraint.
This study investigated the effect of substituting fat-free pota-
to chips made with olestra for regular, full-fat potato chips in an
afternoon snack over two 10-d periods. This manipulation was
done both covertly (no-information condition), where partici-
pants were unaware that they received fat-free potato chips, and
overtly (information condition), where participants were given
nutrition information on the bags of potato chips. Because per-
sonal characteristics such as sex and dietary restraint have been
shown to affect the regulation of food intake, participants were
grouped by sex and dietary restraint status. We hypothesized that
persons in these groupings would respond differently to the sub-
stitution of the fat-free potato chips for the regular potato chips
and to the information provided about the potato chips.
SUBJECTS AND METHODS
Subjects
Participants in this experiment were 95 students, staff, and
community members from the University Park campus and State
College area. They were recruited via newspaper advertisements
and fliers distributed around the Pennsylvania State University
campus. All participants selected for this study were nonsmok-
ers, in good general health, aged 18–40 y, not dieting or engaged
in athletic training, and not currently taking medications that
affect appetite and had no history of or current problems with
food allergies, eating disorders [assessed by the Eating Attitudes
Tests (22)], or depression [assessed by the Zung Depression
Scale (23) and the Beck Depression Inventory (24)]. Participants
also consumed regular snacks and both liked and were willing to
eat potato chips. Fifty-one men and 44 women completed the
protocol. Subject characteristics are listed in Table 1. This pro-
tocol was approved by the Institutional Review Board of The
Pennsylvania State University.
Participants were categorized according to sex and restraint
status (restrained or unrestrained). Participants also represented
a range of body mass indexes. Restraint status was determined
EFFECT OF FAT-FREE POTATO CHIPS ON FAT AND ENERGY INTAKES 283
TABLE 1
Characteristics of participants
1
Cognitive
Age Weight Height BMI restraint
2
Disinhibition
3
y kg m kg/m
2
All participants (n = 95) 23.1 ± 0.6 78.8 ± 2.3 1.7 ± 0.0 26.5 ± 0.7 7.1 ± 0.5 4.8 ± 0.3
No information (n = 44)
Unrestrained males (n = 14) 24.0 ± 1.0 92.2 ± 7.4 1.8 ± 0.0 28.5 ± 1.8 2.6 ± 0.6 4.8 ± 1.0
Restrained males (n = 10) 25.9 ± 2.0 88.3 ± 6.1 1.8 ± 0.0 28.3 ± 1.9 10.2 ± 0.6 3.2 ± 0.6
Unrestrained females (n = 11) 25.5 ± 2.2 74.3 ± 5.7 1.7 ± 0.0 26.9 ± 2.1 4.0 ± 0.9 6.0 ± 1.5
Restrained females (n = 9) 23.4 ± 2.4 66.6 ± 3.3 1.6 ± 0.0 24.8 ± 1.4 12.6 ± 1.0 5.9 ± 0.8
Information (n = 51)
Unrestrained males (n = 14) 22.3 ± 1.2 83.8 ± 5.7 1.8 ± 0.0 26.3 ± 1.6 3.1 ± 0.3 4.4 ± 0.6
Restrained males (n = 13) 20.9 ± 0.5 86.3 ± 6.6 1.8 ± 0.0 27.6 ± 2.0 10.1 ± 0.6 4.4 ± 0.6
Unrestrained females (n = 14) 22.9 ± 1.8 67.8 ± 6.4 1.6 ± 0.0 25.5 ± 2.3 4.9 ± 0.8 5.0 ± 1.0
Restrained females (n = 10) 20.1 ± 0.6 64.8 ± 2.7 1.7 ± 0.0 23.5 ± 0.9 13.8 ± 0.6 4.6 ± 1.0
1
x
–
± SEM.
2
Cognitive restraint score (22).
3
Disinhibition score (22).
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by administration of the Three-Factor Eating Questionnaire
(TFEQ) (25). For women and men, cognitive restraint scores of
≥10 and ≥9, respectively, were considered to indicate restrained
status. Scores below these thresholds were considered to indicate
unrestrained status.
Foods
Both regular and fat-free potato chips were manufactured and
supplied by the Procter & Gamble Co (Cincinnati) (Table 2).
Because of the length of time of the experiment (9 mo), 2 batch-
es of potato chips were used. Both types of potato chips (regular
and fat free) were manufactured in both batches and were pack-
aged in bags containing 170 g potato chips. To ensure freshness,
the potato chips were stored by the Procter & Gamble Co at
258C and shipped every 2 wk to the test site, where they were
stored at room temperature. For the no-information condition,
both types of potato chips were presented in bags labeled “pota-
to chips.” Because the experimenters were blinded to the type of
chips being presented to the participants in the no-information
condition, the bags were identified by an inconspicuous code
number on the label. This code was not broken until the study
ended. In the information condition, the bags of fat-free potato
chips were labeled “fat-free potato chips” and had a correspond-
ing nutrition facts label. The regular potato chips said “potato
chips” and also had a corresponding nutrition facts label. One
liter of tap water at 48C was also provided.
Procedure
Orientation session
All participants in the study attended an orientation session in
which research personnel gave an overview of the experimental
procedure and demonstrated the participant’s role via a mock
session. Participants were told to eat a similar breakfast and
lunch and maintain a similar activity level on each of the days
before coming to the laboratory for their session. The partici-
pants were also taught proper methods for completing visual
analog scale (VAS) (26) booklets and daily habit and health
sheets (for recording any changes in health status or in eating or
activity routines). During the orientation session, participants
were also given detailed instructions (designed by Victoria H
Castellanos) on how to complete 24-h diet records with the use
of food models and measurement devices as examples.
Experimental facility and schedule
Participants came to the test site every afternoon between
1330 and 1630, Monday through Friday, for two 2-wk periods.
The testing area consisted of 3 long cafeteria-style tables parti-
tioned into 18 private cubicles. During a given 2-wk period, the
participants received the same type of chip (regular or fat free)
each day. After the first 2-wk period, there was a 1-wk washout
period in which no testing was performed. There was then anoth-
er 2-wk testing period in which the participants received the
alternate type of potato chip (regular or fat free) each day under
the same protocol. The order in which the chips were presented
was determined by random assignment within condition-sex-
restraint groupings.
Experimental sessions
Researchers logged the participants’ arrival times and hand-
ed them a shopping bag that contained two 170.0-g bags of
potato chips, one 1-L bottle of chilled water, one 237-mL paper
cup, and one napkin. At the beginning of each session, partici-
pants were asked to record on their daily habit-health sheet
whether they ate their usual lunch, maintained their usual activ-
ity level, and felt good or bad or had any change in health over
the past 24 h.
On each day of the experiment, the participants were asked to
rate their hunger, thirst, fullness, desire to eat, and nausea in the
VAS booklet both before and after consuming their snack. On
Tuesdays and Thursdays participants were given an additional
VAS booklet to rate attributes of the potato chips (taste, texture,
and desire to eat) and to estimate the amount of energy, carbo-
hydrate, and fat in the potato chips. Appetitive and hedonic rat-
ings were assessed with a VAS, which instructed the participant
to rate an attribute by asking a bipolar question (eg, How pleas-
ant is the taste of this food?) anchored with its extremes (eg, not
at all pleasant and extremely pleasant) at 0 and 100 mm, respec-
tively, on the linear display of the scale. The schedule for assess-
ment of appetitive (hunger, thirst, nausea, and fullness) and
hedonic (taste, fattiness, carbohydrate content, and saltiness) rat-
ings is summarized in Table 3.
After completing the VAS, participants consumed the potato
chips and water ad libitum. Participants were instructed to eat
the potato chips from a clear bowl (instead of directly from the
bag). They were permitted to stay as long as they liked to have
their snack (between 1330 and 1630). The University Park
campus newspaper was provided as reading material. Any sup-
plements that contained food pictures or food advertisements
were removed from the newspaper. Participants could also read
novels during their snack session; however, reading textbooks
or other newspapers or doing homework or professional work
was not permitted. Prerecorded music was played during the
snack session.
Participants were aware at the beginning of the study that they
would be asked to record their food and beverage intakes on
Wednesdays during the study. Three times during the 2-wk peri-
od the participants completed a sensory-specific satiety test (test
results available from DL Miller, VH Castellanos, DJ Shide, JC
Peters, and BJ Rolls, unpublished observations, 1997).
When participants were finished with their snack, their depar-
ture time was recorded. The remaining potato chips and water
were weighed and subtracted from the quantity presented to
determine the net amount consumed.
284 MILLER ET AL
TABLE 2
Nutrient content of the potato chips
1
Nutrient Regular chips Fat-free chips
Serving size (g) 30 30
Energy [kJ (kcal)] 686 (164) 318 (76)
Energy from fat (kJ) 360 0
Total fat (g) 9.5 0
Saturated fat (g) 1.9 0
Olestra (g) 0 10.2
Cholesterol (mg) 0 0
Sodium (mg) 144 156
Total carbohydrate (g) 19.1 18.5
Dietary fiber (g) 0.5 0.5
Potassium (mg) 50 50
Vitamin E (mg) 0 21.11
1
Analyses conducted by Procter & Gamble Co, Cinncinati.
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Data analyses
All data were analyzed by using SAS-PC for WINDOWS
(version 6.10; SAS Institute Inc, Cary, NC). Results were con-
sidered significant at a two-tailed significance of P< 0.05.
Daily intake
Daily intake data (both weight and energy) were analyzed
by using repeated-measures analysis of variance (ANOVA). In
these analyses, chip type (regular or fat free) and time (10 d of
measurements) were entered as within-subject repeated fac-
tors, and condition (information versus no information), sex,
and restraint status (unrestrained versus restrained) were
entered as between-subjects factors. The full model was ana-
lyzed for all possible main effects and all interactions with
chip type. In addition, the main effect of time (days 1–10 of
the experimental period) and the interaction of time and chip
type were analyzed. Initially, a 5-way, repeated-measures
ANOVA was conducted that included a body-weight grouping
(lean versus obese). Body weight was not related to any of the
outcome measures. Thus, to simplify this complex design, all
interactions with body weight were excluded from further
analyses.
When significant main effects and interactions were found,
the data were separated for further analyses, with careful con-
sideration of the significant findings and their interpretation in
this study and its hypotheses. Additional interactions were
tested to examine the a priori hypothesis that within-subject
differences would be found between the fat-free and regular
potato chips; thus, interactions with chip type were included in
these simpler models. Post hoc analyses were conducted by
using contrast statements with the appropriate within- or
between-subject error term specified, and Bonferroni adjust-
ments were made according to the number of variables and
group means being compared (27). Post hoc tests were used
only to determine where significant and meaningful group dif-
ferences existed when significant multifactor interactions were
found.
Appetitive and hedonic ratings
Changes in appetitive ratings were calculated by subtracting
the postconsumption from the preconsumption ratings. These
data and the hedonic ratings were analyzed by using a repeat-
ed-measures ANOVA with 2 levels of chip type and the appro-
priate number of times of measure as within-subject factors
and condition, sex, and restraint status as between-subject fac-
tors. The full model was analyzed.
24-h Diet record analysis
Diet records were analyzed by using Nutritionist 4 software
(N
2
Computing, San Bruno, CA) with a database supplemented
with regional, local, and other specialty foods as well as Penn-
sylvania State University food service menus (from dining halls
and student union restaurants). A multiple ANOVA was per-
formed in which energy, fat, carbohydrate, and protein intakes
were considered as dependent variables. The independent vari-
ables included condition, sex, and restraint status as between-
subject factors and chip type as a within-subject factor. These
analyses were performed with and without the intake values
from the potato chips eaten in the experimental session. Multi-
variate effects were considered for the within-subject factors
only (chip type and interactions with chip type). If significant
multivariate effects were found, univariate (with adjusted error
terms for a within-subject, repeated-measure design) analyses
were used to explain the effect. The univariate models included
main effects of the between-subject variables and chip type and
all interactions with chip type.
Post hoc regression analyses
To determine which characteristics were associated with the
tendency to consume more fat-free than regular chips, a differ-
ence score was calculated by subtracting the mean intake of reg-
ular chips from the mean intake of the fat-free chips. A positive
value indicated that more fat-free chips were consumed than reg-
ular chips whereas a negative value meant the reverse. A value of
0 indicated that equal amounts of both types of potato chips were
consumed. This difference score was tested as the dependent
variable with condition (no information or information), body
mass index, the Three-Factor Eating Questionnaire (dietary
restraint, disinhibition, and hunger) (25), nutrition knowledge,
and Zung and Beck Depression scores as independent variables
by using forward stepwise regression.
RESULTS
Discharge and debriefing
Participants given unlabeled chips were not aware that the
potato chips in either 10-d period were different from the other
period or that some of the potato chips in the experiment were
fat- or energy-reduced or contained the fat substitute olestra,
even though the consent form stated that a food additive would
be used in some of the food. In contrast, all of the participants
who received the potato chips with nutrition information indicat-
EFFECT OF FAT-FREE POTATO CHIPS ON FAT AND ENERGY INTAKES 285
TABLE 3
Experimental protocol
1
Monday, Tuesday, Wednesday, Thursday, Friday,
Measure days 1 and 6 days 2 and 7 days 3 and 8 days 4 and 9 days 5 and 10
Intake ✔✔✔✔✔
Appetite rating
2
✔✔✔✔✔
Test SSS test
3
Hedonic Food record
5
Hedonic SSS test
ratings
4
ratings
1
No testing was done on Saturday or Sunday.
2
Visual analog scale (VAS) ratings of hunger, thirst, nausea, amount desired to eat, and fullness, both before and after ad libitum consumption.
3
Sensory-specific satiety testing. Not done on day 6.
4
VAS ratings of taste, carbohydrate, fat, and amount desired to eat (before consumption).
5
Twenty-four–hour food diary record.
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ed that they were aware that they were given fat-free potato chips
for 10 d and regular potato chips for the other 10 d. Of the par-
ticipants who received information, 65% were able to accurately
recall the amount of fat and energy listed on the label for both
types of potato chips and 35% were not able to do this accurate-
ly; however, all subjects indicated that the fat-free potato chips
were lower in fat and energy than the regular potato chips.
Potato chip intake
The full model showed a main effect of sex (P< 0.0001).
Males consumed more potato chips (69 ± 1 g; x
–
± SEM) than did
females (40 ± 1 g). There was also a chip-type by condition by
restraint class interaction (P< 0.010). In the no-information con-
dition, there was a main effect of chip type (P< 0.018); partici-
pants ate significantly more regular potato chips than fat-free
potato chips (60 ± 4 g and 55 ± 5 g, respectively). There was no
difference in intake between the restrained and unrestrained par-
ticipants when no information was provided (Table 4).
In the information condition, there was an interaction of
restraint class by chip type (P< 0.011). Unrestrained participants
ate similar amounts of both the fat-free (49 ± 6 g) and regular
(54 ± 7 g) potato chips, whereas restrained participants ate signi-
ficantly more fat-free potato chips (60 ± 7 g) than regular chips
(50 ± 17 g) (Table 4).
There were no significant main effects of or interactions with
day of measure between the types of potato chips in the no-infor-
mation or information conditions. Also, there were no systemat-
ic trends in intake over the 10 d of measurement in either condi-
tion (Figure 1).
Energy intake
When potato chip intake was analyzed as energy intake, there
was a 4-way interaction of condition by chip type by sex by
restraint class (P < 0.0001). Post hoc analyses indicate that all
groups, regardless of condition, sex, or restraint class, consumed
significantly less energy in the snack when eating the fat-free
chips than when eating the regular chips (Table 4).
Twenty-four–hour fat and energy intakes
A main effect of chip type (P< 0.0001) was found in multi-
variate models for 24-h intake (including potato chip intake).
Univariate analyses showed that, on average, participants con-
sumed less fat (P< 0.0001) and protein (P< 0.0001) over 24 h
when they ate the fat-free chips than the regular chips (Table 5).
When potato chip intake was excluded from these analyses,
energy and fat intakes were not different.
Appetitive and hedonic ratings
Appetitive ratings
There were no significant differences in hunger satisfaction,
thirst satisfaction, fullness, or nausea indexes between the 2
conditions or chip types over the 10 measurements or between
any of the grouping variables.
Hedonic ratings
There were no significant differences in ratings of pleas-
antness of taste between the conditions or chip types or any
interactions between chip type and the other grouping vari-
ables. Furthermore, there were no systematic changes in
taste ratings over the 4 measurements for males or females.
There was a significant effect of condition (P< 0.0001) on
ratings of amount of fat and energy. Further analyses showed
that in the no-information condition there were no differ-
ences between chip types or any systematic changes over
time in ratings of saltiness, amount of carbohydrates, or
amount of energy. However, in the information condition,
participants rated the regular chips as having significantly
more fat and energy than the fat-free chips.
Post hoc regression analyses
The best model for predicting the difference in amount
consumed of the 2 types of potato chips included informa-
tion (condition), dietary restraint score, and scores from the
Beck Depression Index (R
2
= 0.17, P< 0.0001). In this
model, provision of information was associated with
increased consumption of fat-free chips compared with the
regular potato chips. Also, as the level of dietary restraint
increased so did the tendency to consume comparatively
more fat-free than regular chips. In contrast, rising scores on
the Beck Depression Index were related to increased intake
of the regular chips.
286 MILLER ET AL
TABLE 4
Potato chip intake during the laboratory snacking session
1
Regular chips Fat-free chips
Group Weight Fat Energy Weight Fat Energy
g g kJ g g kJ
All participants (n = 95) 56 ± 317± 1 1280 ± 78 54 ± 3 0 576 ± 35
2
No information
Unrestrained males (n = 14) 68 ± 521± 2 1554 ± 114 65 ± 6 0 689 ± 68
2
Restrained males (n = 10) 74 ± 14 23 ± 4 1692 ± 317 74 ± 13 0 784 ± 136
2
Unrestrained females (n = 11) 59 ± 719± 2 1349 ± 157 50 ± 6 0 530 ± 61
2
Restrained females (n = 9) 32 ± 10 10 ± 3 732 ± 182 25 ± 5 0 265 ± 56
2
Information
Unrestrained males (n = 14) 64 ± 922± 3 1577 ± 212 60 ± 9 0 636 ± 94
2
Restrained males (n = 13) 63 ± 11 20 ± 3 1311 ± 230 72 ± 11 0 763 ± 121
2
Unrestrained females (n = 14) 39 ± 10 12 ± 3 892 ± 223 38 ± 7 0 403 ± 73
2
Restrained females (n = 10) 35 ± 411± 1 800 ± 92 44 ± 6
3
0 466 ± 59
2
1
x
–
± SEM.
2
Significantly different from the energy intake of the regular chips within the respective group, P < 0.05.
3
Significantly different from the weight intake of the regular chips within the respective group, P < 0.05.
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Daily health
There were no significant differences in the occurrence of ill-
ness or malaise related to the consumption of the 2 types of pota-
to chips. Reported changes in health status included (for fat-free
and regular chips, respectively) cold and flu symptoms (4 and 7),
hangover symptoms (2 and 1), headache (4 and 4), menstrual
discomfort (5 and 0), vertigo and dizziness (8 and 0), nausea (3
and 2), diarrhea and gastrointestinal distress (4 and 9), kidney
infection (1 and 0), mouth ulcer (1 and 0), and ear ache (1 and
1). These reports were out of a possible 950 (95 participants who
completed the protocol 3 10 measurement times) episodes for
each type of potato chip, or 1900 total episodes. None of these
changes in health status affected participation in the study or the
results. No significant changes in body weight occurred in any
group as a result of consuming either type of potato chip over the
10-d periods.
DISCUSSION
This study provided an opportunity to look at 2 separate and
important questions regarding the use of reduced-fat foods. First,
will consumption of palatable fat-free snack chips made with
olestra be associated with a reduction in fat and energy intakes
during a snack and over 24 h? This question is meaningful today
when 137 million Americans (< 75% of adults) regularly con-
sume reduced-fat foods (8) and 49% of those reduced-fat food
consumers report eating reduced-fat snack foods (8). The rea-
sons many consumers give for choosing reduced-fat foods are
primarily related to health and include a desire to reduce fat and
energy intakes (8). In addition, many individuals who are
attempting to reduce weight expect reduced-fat and fat-free
foods to be useful in weight loss (9). Thus, it is important to sys-
tematically investigate the effect that reduced-fat and fat-free
foods have on short-term (during the meal or snack) and longer-
term (over 24 h) fat and energy intakes.
Results here indicate that when individuals ate the fat-free
potato chips made with olestra they consumed significantly less
fat and energy during a snack than when they ate the regular
potato chips. This short-term fat and energy reduction associated
with eating the fat-free potato chips was seen in all groups test-
ed regardless of restraint status or whether the subjects were pro-
vided with nutrition information. Furthermore, there was no sys-
tematic trend to increase or decrease intake of either the regular
or fat-free potato chips over the 10 d of measurement (ie, the
amount of potato chips consumed was stable over time and for
the 2 types of potato chips). Because the fat-free potato chips
contained 10.5 kJ/g (2.5 kcal/g) and the regular potato chips con-
tained 22.6 kJ/g (5.4 kcal/g), participants would have to have
eaten more than twice the amount of the fat-free potato chips to
equal the energy of the regular potato chips. No participant test-
ed ate enough fat-free potato chips to negate the energy reduc-
tion.
These results are consistent with other studies in which par-
ticipants were fed entire diets restricted to foods with certain
EFFECT OF FAT-FREE POTATO CHIPS ON FAT AND ENERGY INTAKES 287
FIGURE 1. Intake of regular (u) and fat-free (olestra-containing; s) potato chips during the no-information and information conditions. n = 95;
x
–
± SEM.
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amounts of fat and allowed to eat those foods ad libitum. In 2
studies conducted at Cornell University, participants were fed
diets that were either high in fat (45% of energy from fat) or low
in fat (25% of energy from fat); participants were free to eat
unlimited quantities of the available foods at the prescribed fat
level (28, 29). The results showed that participants ate similar
weights of food regardless of the fat or energy content of the
diet, which resulted in significant reductions in fat and energy
intakes when the low-fat diet compared with the high-fat diet
was eaten. Thus, these studies and the present study indicate that
individuals eat the same amount of food regardless of fat and
energy contents. Eating similar weights of foods that are lower
in fat and energy compared with the typical diet or food must
lead to reductions in fat and energy intakes.
In this study we also investigated the effect of consuming the
fat-free and regular potato chips on fat and energy intakes over
the subsequent 24-h period. No restrictions were placed on intake
by participants during this period. Participants recorded all foods
and beverages consumed in 24-h food diaries. Food diaries were
kept 1 day each week, and although participants were aware of
the days they would be keeping food diaries, they were asked to
not change their daily food intake or exercise patterns during the
study. The participants were properly trained in keeping the 24-h
food records and were encouraged to provide research personnel
with the food labels from foods consumed. Thus, these measures
provided us with a general picture of the effect of the fat-free
potato chips on daily intakes. Data from food diaries should be
interpreted cautiously because of the potential errors and biases
in using self-reported intake measures (30).
Participants consumed significantly less fat over 24 h when
they ate fat-free chips (68 ± 3 g) instead of regular potato chips
(91 ± 3 g) in their snack, resulting in an average reduction in fat
intake of 23 g over the course of the day. Because there were no
differences between the 24-h intakes when the potato chip intake
was excluded from the analyses, the differences in 24-h fat
intake were due largely to the potato chip intake during the
snack. Energy intake, however, was not different over the 24 h
even though the fat-free potato chips were also substantially
reduced in energy, indicating that the energy difference between
the potato chips was not large enough to significantly reduce
total 24-h energy intake. Thus, this study indicates that replacing
a high-fat snack food with a palatable fat-free alternative in a
single snack can have a significant effect on 24-h fat intake but
may not lead to significant 24-h energy reductions.
Fat reductions but not energy reductions were observed in
other studies in which the fat content of foods was manipulated
with olestra. A study in young men that used a preloading para-
digm in a breakfast meal showed that over 24 h the men reduced
their fat intake but their energy intake was unchanged (31). Sim-
ilar results were seen in a study that used olestra to reduce the fat
and energy content of the diet for children (32). Other studies
showed both fat and energy reductions when sucrose polyester
was substituted for fat (20, 33, 34). These studies, however,
either incorporated the fat substitute in multiple meals across the
day (33) or made manipulations that resulted in surfeits of fat
and energy rather than reductions (20, 34). These results suggest
that the effect of fat substitutes, such as olestra, on energy intake
may be different when substitutions are made in a number of
meals across the day instead of just one meal or snack.
The present study also investigated whether providing infor-
mation about the fat and energy content of palatable snack foods
would affect fat and energy intakes. To accomplish this, we con-
ducted this study in 2 conditions: information (nutrition labels
were provided on potato chip bags) and no information (no
labels were provided). Investigating the effect of such labeling is
important today when many products carry labels stating that
they are fat free or low fat, and people are often aware of the
energy and macronutrient contents of the foods that they choose
to eat. There is evidence that this awareness can affect how foods
are eaten (10–15). Although the laboratory setting in this exper-
iment was different from the natural environment, presenting the
fat-free potato chips with “Fat-Free Potato Chips” printed on the
bag and in the nutrition facts information is a more externally
valid method for assessing how such products will be consumed
in real-life situations than a covert substitution of fat-free potato
chips for regular potato chips.
The results showed that participants in the no-information
condition ate slightly (5 g) more regular potato chips than fat-
288 MILLER ET AL
TABLE 5
Twenty-four–hour fat and energy intakes including the laboratory potato chip consumption
1
Regular chips Fat-free chips
Group Fat Total energy Energy from fat Fat Total energy Energy from fat
gMJ%gMJ%
All participants (n = 95) 91.3 ± 3.2 11.0 ± 0.3 30.8 ± 0.7 67.5 ± 3.0
2
10.2 ± 0.3 24.0 ± 0.7
3
No information
Unrestrained males (n = 14) 112.6 ± 8.8 12.6 ± 0.7 34.0 ± 1.9 79.9 ± 8.4
2
11.4 ± 0.8 25.3 ± 1.9
3
Restrained males (n = 10) 102.2 ± 8.9 12.3 ± 0.7 31.4 ± 1.9 58.3 ± 7
2
11.6 ± 0.8 18.4 ± 1.5
3
Unrestrained females (n = 11) 93.2 ± 8.3 10.7 ± 0.9 32.9 ± 2.0 69.3 ± 7.0
2
9.3 ± 0.8 28.3 ± 2.3
3
Restrained females (n = 9) 79.6 ± 12 8.8 ± 0.9 32.8 ± 2.3 67.6 ± 9.3
2
8.8 ± 1.0 29.0 ± 2.4
3
Information
Unrestrained males (n = 14) 100.1 ± 8.9 12.1 ± 0.7 30.1 ± 1.6 70.2 ± 8.4
2
10.3 ± 0.6 24.3 ± 1.5
3
Restrained males (n = 13) 90.7 ± 8.7 11.4 ± 0.8 30.1 ± 1.2 78.3 ± 9.8
2
11.6 ± 0.6 23.5 ± 1.7
3
Unrestrained females (n = 14) 79.9 ± 7.2 9.9 ± 0.9 30.6 ± 1.7 69.2 ± 7.1 9.9 ± 0.9 26.2 ± 1.7
3
Restrained females (n = 10) 65.7 ± 8.9 9.9 ± 0.8 23.6 ± 1.5 41.6 ± 4.1
2
9.2 ± 1.0 17.7 ± 1.4
3
1
x
–
± SEM.
2
Significantly different from fat intake with the regular chip within the respective group, P < 0.05.
3
Significantly different from the percentage of energy from fat consumed with the regular chips within the respective group, P < 0.05.
by guest on July 13, 2011www.ajcn.orgDownloaded from
free potato chips (Table 4). This effect did not differ between the
restrained and unrestrained groups. Debriefing interviews at the
end of the study confirmed that participants in the no-informa-
tion condition were not aware that the potato chips differed in fat
and energy contents and believed that the potato chips used were
comparable in fat energy with typical full-fat, store-bought pota-
to chips. Hedonic measures also indicated that there were no dif-
ferences in pleasantness of taste or texture between the 2 types
of chips. In contrast with the results from the no-information
condition, restrained participants in the information condition,
who were aware of the fat and energy differences between the
potato chips (also confirmed by the debriefing interviews), con-
sumed significantly more fat-free chips (10 ± 3 g) than regular
chips (Table 4). Despite the increased consumption of fat-free
chips by the restrained participants, all groups significantly
reduced their energy consumption in the snack when they ate the
fat-free chips compared with the regular chips. Thus, the results
of the present study indicate that individuals who are most con-
cerned about body weight (restrained) are more likely to eat
increased quantities of reduced-fat foods. The prevalence of
restrained eating in the general population is unknown because
no large-scale, nutrition-related studies have investigated this
issue.
This relation between dietary restraint status and the effect of
providing nutrition information was confirmed by post hoc
regression analyses that indicated that individuals most likely to
eat comparatively more fat-free potato chips than regular chips
were those who had higher dietary restraint scores and who were
provided information about the product. Interestingly, body mass
index and classification as obese (>20% ideal body weight) were
not related to an increased intake of fat-free chips. Restrained
individuals may not perceive eating increased quantities of fat-
free food as a violation of their self-imposed dietary restrictions.
This increased consumption is a relatively small effect (10 ± 2
g); however, a larger effect may occur outside the laboratory set-
ting. This tendency of people who are concerned about their
body weight to eat increased amounts of reduced-fat and fat-free
foods needs further investigation.
Similar to the present study, most studies investigating the
effect of labeling on food intake found that exposure to a “fat
free” or “low fat” label resulted in increased food intake (10–17,
20). Other labeling studies that had contrasting results did not
consider restrained individuals separately (18, 19). Distinguish-
ing restrained eaters may be important in demonstrating the
effects of information on intakes of reduced-fat foods.
Health practitioners who provide dietary counseling to
patients should consider the personal characteristics of the
patient when recommending the use of foods made with olestra
or other reduced-fat foods as part of a dietary regimen. Such rec-
ommendations should be based on the goals of the patient (eg,
cardiovascular fitness and weight loss). Although people who
were actively dieting were excluded from this study, if weight
loss is a goal when using fat-reduced products, it is important to
note that weight loss is better achieved by reducing both fat and
energy than by restricting fat intake alone (35). To effectively
use fat-substituted foods for weight loss, individuals have to
choose reduced-fat foods that are also reduced in energy, con-
sume these fat- and energy-reduced foods in amounts equal to
those for regularly consumed high-fat foods (ie, not eat addi-
tional foods to make up for reductions in fat or energy), and
incorporate these behaviors into a regular, long-term diet.
Overall, this study indicates that fat-free chips made with
olestra are helpful in reducing fat intake. In addition, individuals
concerned about their body weight should be careful not to
overeat fat-free or reduced-fat foods. Studies are needed to deter-
mine the effects on fat and energy intakes of using fat-substitut-
ed foods in more naturalistic settings over an extended period of
time as well as the effects of using several fat-substituted foods
over the course of the day.
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