J Vet Intern Med 2007;21:1203 1208
A High-Protein, High-Fiber Diet Designed for Weight Loss Improves
Satiety in Dogs
Micka�l Weber, Thomas Bissot, Eric Servet, Renaud Sergheraert, Vincent Biourge, and Alexander J. German
Background: Weight-loss programs for dogs are often hampered by increased begging and scavenging behavior that ensues
when food intake is restricted.
Hypothesis: A diet formulated to contain a high content of both protein and fiber is more satiating than diets that contain
only high fiber or high protein.
Animals: Six entire female adult dogs (2 Shetland Sheepdogs, 2 Brittany Spaniels, 2 Labrador Retrievers) participated in the
satiety studies; 105 adult female dogs of various breeds and ages were used for the palatability studies.
Methods: Three diets (high protein [103 g/1,000 kcal] high fiber [60 g/1,000 kcal] [HPHF]; high protein [104 g/1,000 kcal]
moderate fiber [35 g/1,000 kcal] [HP]; moderate protein [86 g/1,000 kcal] high fiber [87 g/1,000 kcal] [HF]) were tested.
Voluntary food intake was measured in 5 sequential crossover studies, and palatability was assessed with food preference
tests.
Results: Protein digestibility was significantly lower for HF (mean 6 SD; 77.7% 6 2.52%) than for both HPHF (81.1% 6
0.96%) and HP (81.1% 6 1.65%) (P , .001). Short-term food intake (food ingested when offered for 15 minutes every hour
for 4 hours) was lower for HPHF than for both HP and HF (P 5 .038). Medium-term intake (food ingested when offered
3 hours after first meal) was lower for both HPHF (27 6 22.2 kcal/kg0.73) and HF (41 6 6.8 kcal/kg0.73) than for HP (57 6 18.8
kcal/kg0.73) (P 5 .041). Voluntary food intake 3 hours after feeding a restricted meal (25% daily maintenance energy
requirements) was significantly lower on the HPHF diet than on either the HP(251%, P 5 .0051) or HF (247%, P 5 .014)
diets. However, there was no significant difference between the energy intake on the HP and HF diets (7%, P 5 .37). The
HPHF and HP diets had equivalent palatability, and both were more palatable than the HF diet (P , .001).
Conclusions and Clinical Importance: The HPHF diet had a satiating effect as evidenced by reduced voluntary intake
compared with HP and HF diets, and has the potential to lead to greater compliance in weight-loss programs.
Key words: Appetite; Canine; Obesity; Weight loss.
verweight and obesity are common in dogs, and protein,11 fiber,12,13 carbohydrates,14,15 or water7 are the
predispose to a variety of diseases and decreased most satiating.
O
longevity.1 Although pharmaceuticals recently received The results of many human studies showed that
approval for the treatment of weight loss,2 the conven- absorption of macronutrients is lower after consumption
tional strategy for managing obesity involves dietary of high-protein foods than after consumption of foods
energy restriction combined with increasing activity with a high carbohydrate or fat content.16 20 The amino
levels. Weight-loss programs are successful in experi- acids from the digestion of proteins are absorbed slowly,
mental trials3 5 but do not perform as well in practice.6 A and the main path of their metabolism is gluconeogenesis.
major hurdle is that energy restriction causes hunger, Therefore, proteins are sources of glucose that induce
leading to increased begging and scavenging activity. little insulin secretion and delay the appearance of
This puts increased strain on the owner-animal bond, hypoglycemia (which contributes to the feeling of
causing owner noncompliance or complete withdrawal hunger). The satiety effect of proteins is variable, because
from the program. Therefore, developing strategies to the speed of digestion varies among different proteins,
improve satiety would greatly assist in case manage- and different amino acids induce the secretion of insulin
ment. Satiety is defined as the feeling of fullness and to varying degrees. However, there is limited work in the
disappearance of appetite after a meal.7 Dietary factors dog on the effect of dietary proteins on satiety.
can influence satiety, and evidence in humans suggests Under certain conditions in humans, dietary fiber may
that some foods may be more effective than others in exert a satiety effect, although some studies failed to detect
reducing hunger, likely because of the influence of a significant reduction in appetite.20 There are similar
macronutrients in the diet.8 10 Foods high in either discrepancies in studies of dogs, with some21,22 but not all23
studies that suggested effects on satiety. Apparent
inconsistencies are likely the result of differing investiga-
tive methods and of the dose and type of fiber used. High
From the Royal Canin Research Center, Aimargues, France
dietary fiber might increase satiety in dogs, most likely by
(Weber, Bissot, Servet, Sergheraert, Biourge); and the Department
of Veterinary Clinical Sciences, University of Liverpool, Neston, causing gastric distension and cholecystokinin release and
Wirral, UK (German).
a subsequent slowing of gastric emptying.21,24
Reprint requests: Alex German BVSc PhD CertSAM DipEC
Diets currently available for weight management in
VIM-CA MRCVS, Department of Veterinary Clinical Sciences,
dogs include high fiber moderate protein diets and high
University of Liverpool, Chester High Road, Neston, Wirral, CH64
protein moderate fiber diets. Given the evidence that
7TE, UK; e-mail: [e-mail].
suggests that both protein content and fiber can
Submitted January 1, 2007; Revised March 8, 2007, April 11,
influence satiety, we were interested in examining the
2007, May 1, 2007; Accepted May 25, 2007.
effect of both components, alone or in conjunction, on
Copyright 2007 by the American College of Veterinary Internal
E
diet consumption in dogs. Our hypothesis was that a diet
Medicine
0891-6640/07/2106-0007/$3.00/0 formulated to contain a high content of both protein
1204 Weber et al
Table 1. Composition of the diets used to determine satiety in dogs.
Diet
HPHF HP HF
ME contenta 2,900 kcal/kg 3,275 kcal/kg 2,660 kcal/kg
g/100 gb g/1,000 kcalc g/100 gb g/1,000 kcalc g/100 gb g/1,000 kcalc
Moisture 8 28 9 27 9 34
Protein 30 103 34 104 22.8 86
Fat 10 34 10 31 7.5 28
Crude fiber 17.5 60 11.5 35 23.2 87
Total dietary fiber 28 97 18.5 56 35 132
Ash 5.3 18 7.9 24 4.9 18
Fiber sources Cellulose, beet pulp, FOS, psyllium husk Cellulose, beet pulp Mainly cellulose
List of Vegetable fibers, dehydrated poultry meat, Dehydrated poultry meat, Ground maize, ground peanut hulls,
ingredients maize, wheat gluten, hydrolyzed animal wheat, maize gluten, cellulose, chicken and turkey meal, soybean meal,
proteins, wheat, maize gluten, animal fats, beet pulp, poultry fat, poultry maize gluten meal, digest, soybean
beet pulp, minerals (Cl, K, Na, Zn, Mn, liver hydrolysates, minerals hulls, vegetable oil, cellulose, flaxseed,
Fe, Cu, I), fish oil, L-tyrosine, FOS, soya (Cl, Na, Ca, Zn, Mn, Fe, Cu, I, salt, L-carnitine supplement, taurine,
oil, psyllium husks and seeds, sodium Se), fish oil, psyllium, taurine, minerals (potassium chloride, calcium
polyphosphate, green tea and grape vitamins (choline, E, C, niacin, carbonate, zinc oxide, ferrous sulfate,
extracts, vitamins (choline, E, C, niacin, B2, calcium pantothenate, B1, copper, manganese), vitamins (choline
B2, calcium pantothenate, B1, B6, A, folic B6, A, folic acid, biotin, B12, chloride, D3, E, thiamine, niacin,
acid, biotin, B12, D3), hydrolyzed D3), antioxidants (BHA, calcium panthotenate, pyridoxine,
crustaceans, taurine, marigold extract, L- propyl gallate), preservatives riboflavin, folic acid, biotin, B12).
carnitine, hydrolyzed cartilage, (potassium sorbate). Contains EU approved antioxidants
antioxidants (BHA, propyl gallate), (BHA, propyl gallate).
preservatives (potassium sorbate).
HPHF, high-protein high-fiber diet; HP, high-protein moderate-fiber diet; HF, high-fiber moderate-protein diet; ME, metabolizable
energy content; FOS, Fructo-oligosaccharide.
a
Measured by bomb calorimetry (data not shown).
b
g/100 g 5 grams per 100 g diet on an as fed basis.
c
g/1,000 kcal 5 grams per 1,000 kcal metabolizable energy.
high in protein and contained a moderate amount of fiber (HP
and fiber would have a greater satiety effect than diets
diet),b whereas the third diet was high in fiber but contained
that contain only high fiber or high protein.
a moderate concentration of protein (HF diet)c (Table 2). Diets
were analyzed for ash, crude protein (calculated from Dumas
Materials and Methods
nitrogen values), and total lipid content by using the Association
Fran�aise de Normalisation methods.26 Total dietary fiber was
Animals
assayed by using methods that adhered to the Association of
Six female adult dogs of 3 different breeds were used for the
Analytical Chemists guidelines,27 whereas energy content was
satiety studies, including 2 Shetland Sheepdogs, 2 Brittany
measured by using an adiabatic bomb calorimeter.d
Spaniels, and 2 Labrador Retrievers. The median age was 7.8 years
(range, 5.4 12.7 years). The median weight before and after the
Experimental Study Protocols to Test Satiety
studies was 20.1 kg (range, 7.9 46.1 kg) and 20.3 kg (range, 8.1
Five sequential studies were performed where the dogs of the
47.2 kg), respectively. The median body condition score25 was 5 of 9
different breeds consumed the 3 test foods based upon a Latin square
(range, 4/9 to 6/9) both before and after the studies. The
design. For all studies, the outcome measure of interest was the
palatability test involved 105 adult female dogs of 22 breeds. All
amount of energy consumed (in kilocalories per kilogram metabolic
animals remained healthy throughout the studies, based on results
body weight [kg0.73]; kcal kg BW0.73) during a 15-minute period of ad
of the physical examination, blood chemistries, and CBC counts.
libitum access to food. However, in studies 1 to 4, the method by
Dogs were housed in closed indoor/outdoor runs and were
which food was offered depended upon the breed: Shetland
exercised outdoors once daily for 2 hours. Housing and treatment
Sheepdogs and Brittany Spaniels were offered an unlimited amount
protocols adhered to European regulatory rules for animal welfare;
of food for the 15-minute period; given the gluttonous nature of
all experimental protocols complied with European Union guide-
Labrador Retrievers and to limit weight gain during the studies, the
lines on animal welfare and were approved by the Royal Canin
amount of food offered at each meal corresponded to 60% of
Committee for Animal Ethics and Welfare.
maintenance energy requirements (MER), where MER 5 132 kcal/
kg0.73. At least 2 meals per day were given in all studies.
Diets
Three complete and balanced diets, purpose formulated for Study 1: Spontaneous Food Intake during the First Meal of
weight loss in obese adult dogs, were used (Table 1). The diets the Day. The first study assessed the spontaneous food intake of
mainly differed in their protein and fiber content: the first diet was each diet, for the first meal of the day, over a period of 10 days.
high in protein and high in fiber (HPHF diet),a the second diet was Dogs were fed 2 meals per day.
Satiety in Dogs 1205
8:00 AM (t0) and at 3:00 PM (t7). For each subject, this protocol was
Table 2. Energy intake (kcal/kg BW0.73) of 3 diets of
applied twice for 3 consecutive days.
differing protein and fiber composition.
Satiety Trial Mean SD Study 5: Satiety Effect of an Energy-Restricted Meal. The final
satiety study evaluated the satiety effect of the diet when fed an
1. Intake at first meal of day
initial amount equivalent to the amount fed a weight-loss protocol
HPHF 44a 21.2
(eg, approximately 50% MER at target weight, divided over 2
HP 69 20.4
meals). At 8:00 AM (t0), each animal was given a meal of 25% of
HF 49a 19.2
daily MER. At 11:00 AM (t3), Labrador Retrievers were fed 60% of
3. Medium-term satiety (0 hour and 3 hours) MER for 15 minutes, whereas Shetland Sheepdogs and Brittany
Spaniels were fed ad libitum at this time point. This protocol was
HPHF t0 44b 18.0
applied for 2 consecutive days.
HPHF t3 27c 22.2
HP t0 67 14.6
HP t3 57 18.8
Palatability Study
HF t0 49b 19.4
A panel of 105 dogs of different sizes participated in food
HF t3 41 6.8
preference tests between the 3 study diets (HPHF, HP, and HF).
4. Long-term satiety (0 hour and 7 hours)
Two diets were compared on each study day, with each test day
HPHF t0 150 78.9
being separated by a day. The order of the comparisons was not
HPHF t7 147 83.1
randomized. For each test, the 2 diets were served, side-by-side, in 2
HP t0 166 93.0
identical bowls. The amount provided in each bowl was equivalent
HP t7 165 94.5
to twice the energy requirements recommended for each dog. At
HF t0 138 70.7
the end of the 15-minute test period, the amount of each food
HF t7 109 50.9
consumed by all dogs was measured. The ratio of consumption was
calculated by the following equation:
5. Satiety after energy-restricted meald
HPHF t0 27 5.2
Ratio A (orB) (%)
HPHF t3 31 23.3
consumption of food A (or B)
HP t3 63e,f 10.2
~ | 100
(consumption of food A z consumption of food B)
HF t0 24 4.0
HF t3 59e,f 18
Protein and Dry Matter Digestibility
BW, body weight; SD, standard deviation; HPHF: High-protein
high-fiber diet; HP: high-protein diet; HF: high-fiber diet; t0, time
Digestibility Trials. Digestibility was assessed in the 3 diets over
5 0 hours; t3, t 5 3 hours; t7, time 5 7 hours.
5 days during satiety studies 3 and 4. Food was given twice daily
a
Energy intake significantly lower than energy intake on HP diet
(at 8:00 AM and 11:00 AM, or 8:00 AM and 3:00 PM, depending on the
(P , .05).
protocol) and water was available ad libitum. Feces were collected
b
At t0, energy intake significantly lower than energy intake on
and maintained at 4uC over 5 days. At the end of each period, the
HP diet (P , .05).
pooled wet feces were weighed, thoroughly mixed with an electric
c
At t3, energy intake significantly lower than intake on HP diet
blender, and aliquots of 100 g were frozen and stored (220uC)
(P 5 .024).
pending analyses.
d
Restricted meal (25% of daily maintenance energy requirement)
fed at t0, ad lib at t3.
e
Analysis. Dry matter (DM) content of food and feces was
At t3, energy intake significantly greater than energy intake on
determined after oven-drying to constant weight at 103uC, whereas
HPHF (P , .05).
f
crude protein was measured from Dumas nitrogen values.
At t3, energy intake significantly greater than for the same diet
Apparent digestibility percentage of DM and crude proteins was
at t0 (P , .05).
then calculated by using the formula:
Apparent digestibility (%)
Study 2: Satiety during Repeated Short-Term Food Exposure. DM=protein intake DM=protein in feces
~ | 100
The objective of this study was to assess the consumption kinetics
DM=protein intake
of each diet when fed hourly for 3 hours. Food was offered for
15 minutes at 8:00 AM (t0), then at 9:00 AM (t1), 10:00 AM (t2), and
11:00 AM (t3). This protocol was applied twice for each diet, on 2 Statistical Analysis
nonconsecutive days.
Statistical analysis was performed with a computer software
package.e Given that the main outcome of interest for weight-loss
Study 3: Medium-Term Satiety Effect. This study assessed the
programs is total amount energy consumed, all data are expressed
satiety effect of the 3 diets 3 hours after initial presentation of food.
as energy intake (kilocalories) per kilogram metabolic body weight
On the study days, each animal was fed for 15 minutes at 8:00 AM
(kg0.73). For the satiety studies, continuous data were first
(t0), then for a further 15 minutes at 11:00 AM (t3). This protocol
confirmed to have a Gaussian distribution. A repeated-measures
was applied for 2 consecutive days.
design was used to assess effects of variables, including diet type,
timing of feeding, and individual variation on total energy
Study 4: Long-Term Satiety Effect. The objective of this study consumed. A Bonferroni procedure was used for post hoc analysis.
was to assess the pattern of food intake when fed 2 meals per day, Satiety studies 2 through 5 were performed consecutively and each
mimicking a typical feeding pattern for many client-owned dogs. study was performed twice; therefore, for statistical purposes, each
On the study days, each animal was given food for 15 minutes at repeat constituted a repetition of the measure on the same
1206 Weber et al
individuals. To take account of this in the statistical analysis, the
results of the 2 repetitions were averaged before performing the
repeated measures design. In contrast, satiety study 1 involved 10
repetitions of the same study design (food intake at the first meal of
the day); therefore, the individual repetitions could be included as
separate points within the same statistical analysis, and   repeti-
tion  included as a separate factor. For the palatability study,
differences between diets were assessed by using a chi-square test.
Digestibility was assessed by one-way analysis of variance, and
Fisher least significant difference (LSD) procedure again was used
for post hoc analysis. Results are expressed as mean 6 standard
deviation , and the level of significance for all statistical tests was
set at P , .05.
Results
Effects on Satiety
Study 1: Spontaneous Food Intake during the First
Figure 1. Box plot of sequential energy intake on 3 diets (high
Meal of the Day. On a twice-daily meal pattern, the
protein high fiber [HPHF], high protein [HP], and high fiber [HF])
amount of food consumed during the first meal of the during 4 meals, each of 15-minute duration, offered at hourly
intervals (t 5 0, t 5 1, t 5 2, and t 5 3). The boxes depict median
day was significantly different among diets (HP 69 6
(horizontal line) and interquartile range (top and bottom of box).
20.4 kcal/kg0.73 versus HF 49 6 19.2 kcal/kg0.73 versus
Energy intake decreased over the 4 meals for all diets, (P , .05),
HPHF 44 6 21.2 kcal/kg0.73; P 5 .0057) (Table 2). There
with the HPHF diet having the greatest proportional decrease.
was significantly greater energy consumption on the HP
Further, at all meals, energy intake was lower on the HPHF diet
diet compared with both the HPHF and HF diets (P 5
than the HP diet at all meals (P , .05). Energy consumption was
.0025 and P 5 .016, respectively). Energy consumption
also lower on HPHF than HF at t2 and t3 (P , .05 for both).
on the HPHF and HF diets did not differ significantly
Energy intake on HF was significantly lower than HP at t0 (P
(P 5 .52).
5 .013).
Study 2: Satiety during Repeated Short-Term Food
HPHF diet at t3 than on either the HP (251%, P 5
Exposure. The second study assessed the short-term
.0051) or HF (247%, P 5 .014) diets. However, there
satiety effect of diets offered for 15 minutes on 4
was no significant difference at t3 between the energy
occasions over a 3-hour period (t0, t1, t2, t3). A
intake on the HP and HF diets (7%, P 5 .37).
significant overall diet effect was noted (P 5 .038), but
post hoc testing did not identify significant differences
Palatability Study
among individual time points.
There was a significant time trend evident for all
A greater number of the 105 dogs preferred the
diets, with energy intake decreasing over the 3 meals
HPHF and HP diets to the HF diet (amount of food
(Fig 1). Energy intake on the HPHF diet decreased by
consumed: 82% HPHF versus 18% HF diet, P , .001;
49% between t0 and t1 (P 5 .036), and by 77% between
71% HP versus 29% HF diet, P , .001), but there was
t1 and t2 (P 5 .047); the proportional decrease in energy
no significant difference in preference between HPHF
intake on the HP diet was 41% between t0 and t1 (P 5
and HP diets (amount of diet consumed 58% HPHF
.041), and 31% between t1 and t2 (P 5 .044); the
versus 42% HF diet, P 5 .11).
proportional decrease in the amount of HF diet
consumed was 28% between t0 and t1 (P 5 .027), and
Digestibility
33% between t1 and t2 (P 5 .045).
DM digestibility of HPHF (61% 6 3.4%) was
significantly lower than that of HP (65% 6 3.0%, P 5
Study 3: Medium-Term Satiety Effect. There was
.009). However, no difference was observed between the
a significant diet effect on food intake (P 5 .0028), and
HF diet (62.5% 6 4.36%) and either the HPHF (P 5
significantly less energy was consumed on the HPHF
.128) or HP (P 5 .074) diets. Protein digestibility was
than on the HP diet (P 5 .041) (Table 1).
significantly lower for the HF diet (78% 6 2.5%) than
for both the HPHF (81% 6 1.0%, P , .001) and HP
Study 4: Long-Term Satiety Effect. When dogs were
(81% 6 1.6%, P 5 .0025) diets.
offered food on a twice daily meal pattern (t0, t7), there
was no significant difference in energy intake between
Discussion
the 2 meals for any diet (P 5 .19) (Table 2).
The current study assessed the effect of 3 diets on the
Study 5: Satiety Effect of an Energy-Restricted Meal. voluntary food intake in dogs. Overall, our results
Energy intake increased significantly between t0 and t3 indicated that a diet formulated to contain high contents
for both the HF (146%, P , .001) and HP (75%, P , of both protein and fiber had a greater satiating effect
.001) diets but not for the HPHF diet (15%, P 5 .27). than did diets formulated to contain higher contents of
Further, significantly less energy was consumed on the either protein or fiber alone. Given that excessive hunger
Satiety in Dogs 1207
and begging behavior are common reasons for owners to standardized, it has the advantage that all of the
withdraw their dogs from weight-loss programs, im- current diets are commercially available and thus is
proved compliance would be expected. The fact that reflective of their use in a clinical setting.
none of the diets had a significant effect on intake over The final part of the satiety study demonstrated that
the longer term (7 hours) could still mean that there the HPHF diet had a satiating effect even when fed at an
might be signs of hunger a number of hours after a meal.
energy-restricted level; the other main study limitation
Thus, additional feeding strategies, such as splitting
was that satiety was not assessed in dogs on a weight-
daily ration over a number of meals, might still be
reduction program. It is not known whether the
necessary to maximize compliance with weight-reducing
satiating effect wanes when a restricted diet is fed
diets.
continually, and this will require a future prospective
Five associated studies were used to assess the dietary study. Nevertheless, the favorable satiety characteristics
effect on satiety. In all studies, the primary outcome
of this current diet suggest it would likely perform better
measure was energy consumption. Initially, voluntary
than if using diets only formulated to be high in protein
intake was assessed during the first meal of the day. The
or in fiber.
second study assessed short-term satiety when providing
A major question in studies on appetite and satiety is
repeated exposure to food in a 3-hour period. The next 2
the method by which satiety is assessed. In humans, this
studies assessed satiety over the medium (3 hours) and
is easy and usually involves rating perception of satiety,
long (7 hours) term, whereas the final study assessed the
with a visual analog scale, after various meals are
satiety effect after an energy-restricted meal (equivalent
consumed.5 However, given that such data cannot be
to the approximate amount that would be fed during
collected in dogs, we chose to monitor voluntary food
a weight-loss program). Overall, the HPHF diet led to
intake as an indirect measure of satiety. Nevertheless,
the greatest reduction in voluntary energy intake during
such an assumption is only valid if there is no difference
the short and medium term, suggesting that it had the
in palatability among diets assessed. Significant differ-
greatest satiating effect. The comparative difference was
ences in palatability were evident in this study, with the
greater between HPHF and HP diets than between
HF diet the least palatable, and the HP and HPHF diets
HPHF and HF diets. Further, the HF diet had a superior
were equivalent in palatability. Therefore, palatability is
effect on satiety than the HP diet.
unlikely to account for the observed differences in food
When taking these results together, it is tempting to
consumption observed, and, in fact, the improved satiety
speculate that both fiber and protein are exerting
effect of the HPHF diet over the HF diet may be more
satiating effects but that the effect of fiber is greater
pronounced given its superior palatability. Although
than that of protein. However, other effects may
a study with diets of identical palatability would have
explain the differences observed. First, the type of fiber
been a more scientific method of assessing the satiating
included in both of the fiber-supplemented diets is
effects of protein and fiber, the use of commercially
different; fiber in the HF diet was mainly derived from
available diets meant that the results of the current study
peanut hulls, soybean hulls, and cellulose; in the HPHF
are more readily applied to the clinic.
and HP diets, cellulose, beet pulp, and psyllium husks
One concern of using a diet high in fiber for weight
(HPHF only) were the main fiber sources. Different
loss is the potential for reduced digestibility, particularly
types of fiber may exert differing effects on satiety.
with regard to protein, because high protein concentra-
Most notably, the results of many studies conducted on
tions in the diet are essential to minimize lean tissue
humans showed that psyllium reduces caloric consump-
loss.32,33 Although there was a significant decrease in
tion while improving satiety.28 30 The action of psyllium
protein digestibility for the HF diet, no difference in
on caloric intake and satiety could result from its
protein digestibility was noted for the HPHF diet. The
capacity to increase chyme viscosity, which slows down
exact reason for this is not clear but may be the result of
gastric emptying, as shown previously in humans28 and
high ileal digestibility of its protein and, therefore, its
dogs.31 To assess the relative effects of both fiber and
low index for indigestible protein.
protein supplementation most appropriately, 4 similarly
In conclusion, the current study demonstrated that
formulated diets would have been needed, which only
a HPHF diet led to improved satiety over diets that were
differed in fiber and protein content (eg, HPHF, HP
supplemented in either HF or HP. This novel approach
only, HF only, and neither HP nor HF). A second
to tackling the problem of hunger may lead to greater
possibility for observed differences among diets is that
acceptance of conventional weight-loss programs in
other nutrient concentrations may also have differed.
companion animals. Further studies will be required to
For example, the contents of fat included were 34 g/
confirm that the favorable characteristics noted in the
1,000 kcal, 31 g/1,000 kcal, and 28 g/1,000 kcal for
current study are maintained when the same diet is fed
HPHF, HP, and HF, respectively. However, although
during a long-term weight-reduction program.
our observations could have been because of fat
content of the diet, all would still be classified as
having   low fat  content compared with standard
maintenance diets for dogs. Hence, the differences are
Footnotes
more likely to be the result of protein and fiber than
a
fat. Therefore, although the current study design was
Satiety Support diet, Royal Canin, Aimargues, France
b
limited because not all other dietary factors were Obesity Management diet, Royal Canin, Aimargues, France
1208 Weber et al
c
r/d; Hill s Pet Nutrition Inc, Topeka, KS 14. Blundell JE, Green S, Burley V. Carbohydrates and human
d
C2000 basic adiabatic bomb calorimeter, IKA, WERKE, Staufen, appetite. Am J Clin Nutr 1994;59(Suppl):728S 734S.
Germany 15. Stubbs RJ, Mazlan N, Whybrow S. Carbohydrates, appetite
e
Statgraphics Plus 5.0, Manugistics Inc, MD and feeding behavior in humans. J Nutr 2001;131:2775S 2781S.
16. Stubbs RJ. Macronutrient effects on appetite. Int J Obes
Relat Metab Disord 1995;19(Suppl):S11 19.
17. Louis-Sylvestre J. Toutes les prot�ines ont-elles le męme
pouvoir sati�togŁne? Cah Nutr Diet 2002;37:313 321.
Acknowledgments
18. Gerstein DE, Woodward-Lopez G, Evans AE, et al.
AJG s senior lectureship is funded by Royal Canin. Clarifying concepts about macronutrients effects on satiation
and satiety. J Am Diet Assoc 2004;104:1151 1153.
19. Bowen J, Noakes M, Clifton PM. Effect of calcium and
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