Bran,. Rice Krispies, and Special-K,. Kellog's,. Battle. Creek,. MI; green pepper steak,. Lean. Cuisine,. Stouffer,. Solon,. OH; spaghetti with meat sauce,. Healthy.
Caloric, but not macronutrient, compensation by humans for required-eating occasions with meals and snack varying in fat and carbohydrate13 Richard W Foltin, Barbara J Rolls, Timothy Amy L McNelis, and Marian W Fischman ABSTRACT assessing
ulations during and afternoon Overall,
participated
ofcovert
macronutrient
three snack)
energy
7000
compensated
and
required-eating occasions on total macronutrient
content
ofthe
kJ (o700
the differential Each condition low CHO; and
in a residential
and
occasions
varied
1700
with
kcal)
study
energy
content
of required
occasions
(breakfast, and energy
lunch, intakes.
effects
o3000
postulate
between majority
required
(high-CHO
condition:
evidence
ential
effects
The
± 2686
Id).
compensation,
ofcondition
no macronutrient
1 356
occasions
U).
± 3314 in the
Only
In
total
contrast
there
on macronutrient
were
intake,
compensation.
Am
J Clin
to the
ie, there
was
feeding
WORDS
Fat, carbohydrate,
compensation,
humans,
caloric
intake,
food
preloads
(6-9). slow
food
with
the
effects
Recently,
a study
even when by > 1674
meals
have
subjects
intake
from
researchers have
example,
to
different
because
of its
emptying,
higher
fat has been proposed CHO, eg, joule-for-joule than
in
mixed
this
will CHO
differential
fat
laboratory
to fat
loads
Subjects of foods and
CHO
with
(10).
contents
respect
to this
demonstrated stable
daily
that energy
ofa mandatory lunch Caloric compensation was derived
was little
and
results
a relatively
the energy intake Id (400 kcal) (18). there
postabsorptive
led
of gastric
more
varying
yielded
maintained
the energy
ma-
the diverse theoretical arguments pertaining regulation ( 1 1 - 1 3), short-term studies assess-
of
on food choice issue (14-17).
and have
For rate
preloads
reduce
of low-fat
macronutrients
slow absorption, efficacy than
compensation. wide range
intake,
these
effects,
will
success
(CHO)
behavior
In accordance to macronutrient
the
in the preabsorptive
carbohydrate
of osmotic
Furthermore, KEY
limit
energy density, and have higher satiating
when
331-42.
differences
would
that joule-for-joule, on
man
1992;55:
of items
of fat and
absence
ing
no differ-
Nutr
large
effects
of
condition ( 12 326 ± 2548 kJ) its matched CHO condition
14 665
for caloric
±
fat content
nipulations.
the
of the
(1 3 297
energy intake under the high-fat was significantly different from clear
the
manip-
derived from either fat or carbohydrate (CHO). (high, medium, and low fat; high, medium, and no required eating) was examined for 2 d. Subjects for the
H Kelly,
energy
such that only under the low-CHO condition (1 1 297 Id) was total daily energy intake lower than that observed absence
Thomas
evidence
from
either
hu-
intake
meal varied was similar fat or CHO.
of macronutrient-specific
had relatively unrestricted access to a the study of food intake was embedded
in the measurement of many behaviors (eg, work performance, social activity), so that the principal interest in food intake was
Introduction In accordance ciation
between
obesity
and
with
cancer
recommending daily addition,
the
of fat intake
from
growing
experts
of a positive disease,
to the
and
in the United
of fat be reduced the
public
led
evidence coronary
nutrition
intake
intake has
growing
fat and
(1), that
energy
the
dietary
current concern
about
development
asso-
States
are
of total
of 35-37%
(2).
the
effects
adverse
of many
ical and
between
to zo30%
total
not readily apparent. Under similar living conditions in other previous research, subjects were sensitive to both pharmacolog-
In
increase for the
from
sources
dieting intake content
several
individuals even when
their intake of fat from other sources to reduction due to the low-fat items. Data indicate maintain provided
(4, 5). Similar
specific
that
under
certain
a relatively with some
conditions
consistent total foods of lower
fat compensation in USA.
creased
MW amines
manipulations
smoked food
intake
Fischman,
that
marijuana, (4,
19, 20; TH
unpublished
decreased
food
and
intake
affect
eating
diazepam Kelly,
observations,
behavior: taken
RW
Foltin,
199 1) and
caloric orally
in-
L King,
amphet-
(21).
commercial
products proclaiming reduced fat, cholesterol, and/or low-density-lipoprotein contents (3). A question that arises from the availability of such products is whether, when presented with numerous low-fat foods, individuals will reduce their fat intake or will they compensate
energy
dilution,
nonenergy energy
for changes © 1992 American
in Society
I From the Division ofBehavioral Biology, Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore. 2 Supported by National Institute ofDiabetes and Digestive and Kidney Diseases grant 39 177 (to BJR). 3 Address reprint requests to RW Foltin, Department of Psychiatry and Behavioral Sciences, The Johns Hopkins School of Medicine, 600 North Wolfe Street, Houck E-2, Baltimore, MD 21205. Received February 1 1, 1991. Accepted for publication May 16, 1991.
for Clinical
Nutrition
331
Downloaded from www.ajcn.org by guest on April 26, 2012
and
Six subjects the effects
H Moran,
FOLTIN
332 The present experiment further relative influence of caloric and
investigated macronutrient
normal-weight
no history
residing
male
subjects,
continuously
observation signed
of human
to test
regulation
the
(1674
study that
the
restraint,
for the long-term
Specifically, that
1(J), and
ofdietary
designed
behavior.
hypothesis
in the previous
differential
with
in a laboratory
the issue of the regulation in
this
absence
study
was
(18) was due to the small with
de-
of macronutrient
a larger
energy
differential
there
would be evidence for macronutrient the maximum differential between with this differential being derived
regulation. In this study conditions was > 4000 Id, predominantly from fat or CHO. As in the earlier study (18), the foods used in this research were commercially available and subjects had experience with them. Thus, the research addressed fat and CHO intakes in the general sense and did not investigate possible differences among various fats or CHOs.
Subjects
and methods
were
paid
for participation.
that they were participating performance stability over nutrition would
They
in a study prolonged
occasions
Johns
Hopkins
each
day.
This
Joint
Committee
in groups
of three,
were
instructed
on the effects of computerperiods of time. Because
can affect performance, they be given food to be consumed
eating
were also told during three
research
was
on Clinical
that they required-
approved
by The
Investigation.
Laboratory Subjects, designed
for
continuous
lived
observation
in a residential of human
laboratory behavior
over
extended periods oftime (25). The facility consisted ofsix rooms connected by a common corridor and was housed within a wing of The Johns Hopkins Hospital. Three identical private rooms were similar to small efficiency apartments with a kitchen, a bathroom, desks, and sleeping areas. The common social area had a recreation room, an exercise room, and a bathroom. The recreation room contained kitchen facilities, lounge furniture, a variety cassette
of games, recorder
puzzles, with
a video
monitor. scale with
tamed an electronic the daily weighing
of subjects.
ercise
(stationary
equipment
The
game
system,
recreation
and room
a videoalso
read-out in the control room The exercise room contained bicycle,
free-weights,
etc.)
con-
for cxand
laundry facilities. Two-way cabinets in each room of the laboratory allowed the transfer of items between subjects and cxperimenters without direct contact. Each private room had an Apple lIe microcomputer (Cupertino, CA) located on the subject’s
desk,
and
room
of the
social
Output from a video and audio monitoring system terminated in an adjacent control room. Subjects were observed continuously except when they were in private dressing areas and toilet facilities. Communication between subjects and experimenters was kept to a minimum and was accomplished by using a networked computer system consisting of the computers in each room of the laboratory and in the main control room. This networked
a similar area.
computer
was
located
in the
main
communication
system
allowed
for continuous
on-
line interaction between subjects and experimenters. Once a day, however, a staff member met with each subject individually to discuss issues related to study participation. Subjects were provided a newspaper each morning and had access to a telephone for making local calls during the evening social-access period. Standard
day
Subjects were awakened at 0900 by a tone that sounded until the subject signaled that he was awake, and the day ended with lights out at 2400. Subjects were weighed each morning in stockfeet
after
voiding.
There
were
two
3-h
work
periods
each
day: 1000- 1 300 and I 330- 1630. During these periods subjects were instructed to remain in their private rooms and engage in one of four computerized work tasks. Subjects selected a task from a list ofoptions presented on each private-room computer monitor. The other options available during these periods were engaging
in eating
or toileting
activities.
Work
tasks
lasted
3
mm
and subjects were given a small bonus at the end of the study on the basis of their performance during each work period (one to four dollars per period, or two to eight dollars per day). At 0930 subjects were provided with a breakfast meal in their private rooms and were given 30 mm to consume the entire meal, and at 1300 subjects were provided with a lunch meal in their private rooms and given 30 mm to consume the entire meal. A final required-eating occasion occurred at 1630, when subjects were given a snack to be consumed within 1 5 mm. A staff member visited each subject individually in his private room at 1645. Beginning at 1700, subjects had access to the activities in the social rooms, ie, a social-access period. Two videotaped films were shown beginning at 1800 and 2 100. Clocks or watches were not permitted but the time appeared on the computers at each activity transition, eg, 0900, 0930, 1000, 1300. During the periods when subjects had access to the social areas, a timesampled record was kept oftheir activity. Once every 2 mm the activity of each subject was recorded as lying, sitting, standing, walking,
exercising,
or being
in the
collected to assess the possibility fat and CHO consumption. Food
bathroom.
These
of activity
changes
data
related
were
to
monitoring
access was controlled. After weighing in each morning, a box of food was placed in the food drawer ofeach ofthe three private rooms. This box contained a wide variety of foods including some meal items, and conventional snack-food items including liquid items (see Appendix A for a complete list of foods), that could be consumed at any time during the experimental day (from 0900 to 0900 the next morning). Snack-item portion sizes were designed to contain a roughly equivalent energy content. Subjects were free to request additional units of any items ad libitum. Frozen meal items were available by request throughout the experimental day. To facilitate choice of frozen meal items, subjects were provided with a book containing the pictures from the front of a box of each of the available Food
Downloaded from www.ajcn.org by guest on April 26, 2012
Six (two groups of three) healthy, adult, male, research volunteers ranging in age from 22 to 32 y [26.8 ± 1.3 y (1 ± SE)] participated in l4-d experiments. All subjects were within accepted weight ranges [77.9 ± 5.7 kg, (22)], had low dietary restraint [self-report score of < 10, (23)1, and had no self-reported eating abnormalities [abnormality score of < 15, (24)]. Four of the six subjects reported smoking between 10 and 20 tobacco cigarettes/d (12.5 ± 2.5) and continued to do so during the cxperiment. Subjects received complete medical and psychiatric evaluations, signed consent forms detailing all aspects of the and
AL
ing
Subjects
research,
ET
FAT, TABLE 1 Characteristics
of the three-planned
eating
CARBOHYDRATE, occasions
under
AND
CALORIC
REGULATION
333
each condition Percent weight
Condition
Low fat Medium
Energy
Protein
g
%
g
%
kJ/g
kJ/g
3092 5158 7051
13.9 60.2 107.8
16.9 43.9 57.6
103.4 111.2 111.7
56.0 36.1 26.5
48.1 59.1 61.1
26.0 19.2 14.5
1032 1107 1244
63 58 59
6.09 10.08 12.17
0.63 0.75 1.21
2939
21.0
26.9
107.1
60.9
29.6
16.8
1383
55
4.56
0.14
5076
21.5
16.0
233.7
76.9
30.3
10.0
1472
52
5.06
1.92
6969
19.6
10.6
346.5
83.2
33.5
8.0
1770
47
5.69
1.92
density
of solid items. of fluid items.
in macronutrient
content
macronutrient
to increase
intake
the
opportunity
as a function
of experi-
condition. were
told
that
their
food
intake
was
continuously
monitored by independent observers and were instructed to inform the research monitors via the computerized communication system whenever they ate or drank something, specifying substance and portion. Wrappers for each food were color coded by subject
to facilitate
data
collection.
Trash
was
removed
and
measured daily to validate verbal reports and observer records offood intake and to control for the possibility offood hoarding. Previous studies indicated that these procedures have no significant effect on total daily intake, and subjects under these conditions are sensitive to manipulations affecting daily amount and patterning of food intake (4, 18-20, 21). A snack was defined as the between-meals consumption of any item contained within the box of food not requiring preparation time. The energy derived from coffee or tea in combination with milk and sugar was classified as snack joules. A meal was defined as the consumption ofany ofthe items that required preparation time, including frozen foods and sandwiches, alone or in combination with any ofthe snack food items. For example, cookies consumed individually were a snack item, but when cookies were consumed with any item requiring preparation time, the combination was classified as a meal. Procedures
foods Also,
occasions
and
rated
as acceptable
all ofthe
frozen
and the items contained in the required-eating occasions. subjects received a day of training on the computerized-
performance
before
tasks.
Subjects
reported
to the
laboratory
on
the
the
study,
were
slept
in the laboratory begin at 0900. Subjects pating
in a study
oriented
to living
in the
so that the first experimental were instructed that they
on the effects
facility, day
were
ofcomputer-performance
and
could particistability
over prolonged periods oftime and because nutrition can affect performance they were required to consume all of the food in the required-eating occasions each day. Subjects had access to all other
available
and
allowed
were
ditional
food.
would
vary
foods
during
to supplement
They over
were
the
told
course
the
required-eating
the
eating
that
occasions
occasions
the required-eating
of the
with
ad-
occasions
experiment.
1 provides
a description ofthe macronutrient and energy contents of the required-eating occasions and Appendix B provides a complete description of the foods presented in these required-eating occasions. The required breakfast meals that varied in fat consisted ofeggs, sausages, and a cake item. The required breakfast meals that varied in CHO consisted ofpancakes, syrup, and fruit. The energy content of breakfast was 850 Id (200 kcal) for the low, 1 700 Id (400 kcal) for the medium, and 2450 Id (600 kcal) for the high conditions. The required lunches conTable
sisted
of a sandwich
energy 500,
content
and
700
respectively. consisted afternoon
required
chocolate
snacks
a carbonated was
1300,
for the low,
kcal) The
ofa
and
of lunch
that
medium,
afternoon cupcake
varied
orange 2150,
and
in CHO
beverage.
and
and
snacks milk,
that whereas
consisted
The
1900 Id (300, high conditions,
ofa
varied
in fat
the required savory
snack
mix and carbonated beverage. The energy content of the afternoon snack was 820,J260, and 1650 Id (200, 300, and 400 kcal) for the low, medium, and high conditions, respectively. The three required-eating occasions contained 30#{174} kJ (700 kcal) under the low-calorie condition, 5l00 Id (1200 kcal) under
A list of possible foods was presented to the subjects before the study and they rated the acceptability of each item and whether they had previously consumed that item. All subjects reported having previously eaten the foods contained in the required-eating
day
the medium-calorie
condition,
and
7000
U (1700
kcal)
under the high-calorie condition. The energy differential was accomplished by manipulating the energy derived from either fat or CHO, resulting in six conditions (low CHO, med CHO, high CHO, low fat, med fat, and high fat). The low-CHO and low-fat conditions were similar with respect to fat and CHO contents. In addition, on the first and last day of each study there were no required-eating occasions, ie, subjects self-selected food during the entire day. Table 2 indicates the order of testing
Downloaded from www.ajcn.org by guest on April 26, 2012
frozen items. In addition, subjects had free access to instant coffee, tea, and water at all times. Both meal and snack items were chosen to provide items varying in fat and CHO contents, and to have a similar number of items high in CHO or high in fat. Such conditions provided subjects with a variety of items
Subjects
Fluid densityt
density*
%
density
mental
Solid
fluid
g
Energy
for differential
from
%
t Energy
varying
Weight
g
Highfat
S
Carbohydrate
U
fat
Low carbohydrate Medium carbohydrate High carbohydrate
Fat
FOLTIN
334
ET
AL
TABLE
2 Experimental
design
ondays
1-14
I Group 1 Condition*
Macronutrient Group 2 Condition Macronutrient S
The low-CHO
5158
2
3
4
5
6
None
Medium
Medium
Low
Low
High
High
None
CHO
CHO
Fat
Fat
CHO
CHO
None None
Medium Fat
Medium Fat
High CHO
High CHO
Low Fat
Low Fat
condition
kJ, the high-CHO
contained
condition
6969
2939 kJ, the low-fat condition Id, and the high-fat
condition
analysis
Experimental days began at 0900 and food intake over the next 24 h was analyzed. Intake during the 2 d when there were no required-eating occasions served as the control condition. The data used in the analyses were based on the subjects’ reports offood intake (verified by weighing oftrash). Data were analyzed by using three series ofplanned comparisons involving repeated measures. In the first series ofcomparisons, data obtained under the low-CHO and low-fat conditions were compared with each of the other conditions. In the second set of comparisons, data obtained under the control condition were compared with each of the other conditions. In the third set of comparisons, data obtained under the med-fat, med-CHO, high-fat, and high-CHO conditions were compared. Total energy intake and energy intake of CHO, fat, and protein [estimated as kilocalories from gram intake by using Atwater factors (26)] were analyzed with and without the caloric content of the items in the required-eating occasions. between
Specifically, either
the
the
following
low-CHO
and
comparisons low-fat
and
the
were
made
control
con-
1) total daily intake; 2) intake during the private condition, ie, when the planned occasions occurred, and social condition; 3) intake derived from snacks and meals; and 4) the interaction between condition and private and social-access period intake. The percent of energy intake derived from each ofthe three macronutrients (with and without the required-eating occasions) were analyzed by using comparisons based only on total daily intake. The proportion of time that subjects spent in the resting categories (ie, lying, sitting, standing, and being in the bathroom) under each condition was ditions
with
each
other
8
9
Medium
Medium
Fat
Fat
Medium CHO
Id. None
indicates
12
13
14
Low
Low
High
High
None
CHO
Fat
Fat
None
High Fat
High Fat
Low CHO
Low CHO
None None
condition
control
11
CHO
Medium CHO
3092 Id, the medium-CHO 7051
10
5076 kJ, the medium-fat
condition
condition.
compared with the low-CHO and low-fat conditions and the control condition. Body weight before the first residential day was compared with body weight on the morning after the last day by using a paired t test. The results for each of the four questions answered during the debriefing taste session for each of the eight food groups were compared by using separate repeated-measures analyses of variance (27). Results were considered statistically significant if P < 0.05.
Results Energy
intake
Table 3 summarizes the total energy content of the plannedoccasions and relates this to the energy intake under the
food
control
conditions.
The
tamed,
respectively,
23%,
under
the control
intake,
including
low,
medium,
39%,
and
and 53%
high
ofthe
conditions energy
con-
consumed
condition. Also listed is the total daily energy the planned occasions compared with intake under the control condition. Figure 1 presents daily energy intake with and without the energy contained in the required-eating occasions as a function ofcondition. Under the control condition subjects consumed 13 297 kJ (3200 kcal)/d. When the energy content of the required-eating occasions was included in the data analysis, only under the low-CHO condition was intake significantly less than under the control condition (F1151 = 9.63, P < 0.027). When compared with energy intake under the low-
TABLE 3 Energy content
of the planned
occasions
and energy intake under
each
condition
Condition
Energy
Percent of control
Total energy intake*
Percent of control
U
%
Ici
%
0 2939
0 22
13297± 1356 11297±3314
100 85t
5076
38
13640±3916
103
6969
52 23 39 53
14665±2686 12401 ±4243 14 364 ± 2761 12326±2548
110 93 108 93
condition:
Control LowCHO
MediumCHO HighCHO Lowfat Medium fat Highfat *
I
3092 5158
7051
± SE.
t Significantly
different
from the control
condition,
P
1
0) C) C LU
intake
3 presents
condition (top),
with
quired-food condition,
derived
6276
Id
similar
intake
during
the
pattern
social-access significantly dition
P
