A High-Protein, High-Fiber Diet Designed for Weight Loss Improves

Satiety in Dogs

Mickae¨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/kg

0.73

) and HF (41 6 6.8 kcal/kg

0.73

) than for HP (57 6 18.8

kcal/kg

0.73

) (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.

O

verweight and obesity are common in dogs, and

predispose to a variety of diseases and decreased

longevity.

1

Although pharmaceuticals recently received

approval for the treatment of weight loss,

2

the conven-

tional strategy for managing obesity involves dietary
energy restriction combined with increasing activity
levels. Weight-loss programs are successful in experi-
mental trials

3–5

but do not perform as well in practice.

6

A

major hurdle is that energy restriction causes hunger,
leading to increased begging and scavenging activity.
This puts increased strain on the owner-animal bond,
causing owner noncompliance or complete withdrawal
from the program. Therefore, developing strategies to
improve satiety would greatly assist in case manage-
ment. Satiety is defined as the feeling of fullness and
disappearance of appetite after a meal.

7

Dietary factors

can influence satiety, and evidence in humans suggests
that some foods may be more effective than others in
reducing hunger, likely because of the influence of
macronutrients in the diet.

8–10

Foods high in either

protein,

11

fiber,

12,13

carbohydrates,

14,15

or water

7

are the

most satiating.

The results of many human studies showed that

absorption of macronutrients is lower after consumption
of high-protein foods than after consumption of foods
with a high carbohydrate or fat content.

16–20

The amino

acids from the digestion of proteins are absorbed slowly,
and the main path of their metabolism is gluconeogenesis.
Therefore, proteins are sources of glucose that induce
little insulin secretion and delay the appearance of
hypoglycemia (which contributes to the feeling of
hunger). The satiety effect of proteins is variable, because
the speed of digestion varies among different proteins,
and different amino acids induce the secretion of insulin
to varying degrees. However, there is limited work in the
dog on the effect of dietary proteins on satiety.

Under certain conditions in humans, dietary fiber may

exert a satiety effect, although some studies failed to detect
a significant reduction in appetite.

20

There are similar

discrepancies in studies of dogs, with some

21,22

but not all

23

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
dietary fiber might increase satiety in dogs, most likely by
causing gastric distension and cholecystokinin release and
a subsequent slowing of gastric emptying.

21,24

Diets currently available for weight management in

dogs include high fiber–moderate protein diets and high
protein–moderate fiber diets. Given the evidence that
suggests that both protein content and fiber can
influence satiety, we were interested in examining the
effect of both components, alone or in conjunction, on
diet consumption in dogs. Our hypothesis was that a diet
formulated to contain a high content of both protein

From the Royal Canin Research Center, Aimargues, France

(Weber, Bissot, Servet, Sergheraert, Biourge); and the Department
of Veterinary Clinical Sciences, University of Liverpool, Neston,
Wirral, UK (German).

Reprint requests: Alex German BVSc PhD CertSAM DipEC

VIM-CA MRCVS, Department of Veterinary Clinical Sciences,
University of Liverpool, Chester High Road, Neston, Wirral, CH64
7TE, UK; e-mail: [e-mail].

Copyright

E

2007 by the American College of Veterinary Internal

Medicine

0891-6640/07/2106-0007/$3.00/0

Submitted January 1, 2007; Revised March 8, 2007, April 11,

2007, May 1, 2007; Accepted May 25, 2007.

J Vet Intern Med 2007;21:1203–1208

and fiber would have a greater satiety effect than diets
that contain only high fiber or high protein.

Materials and Methods

Animals

Six female adult dogs of 3 different breeds were used for the

satiety studies, including 2 Shetland Sheepdogs, 2 Brittany
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
studies was 20.1 kg (range, 7.9–46.1 kg) and 20.3 kg (range, 8.1–
47.2 kg), respectively. The median body condition score

25

was 5 of 9

(range, 4/9 to 6/9) both before and after the studies. The
palatability test involved 105 adult female dogs of 22 breeds. All
animals remained healthy throughout the studies, based on results
of the physical examination, blood chemistries, and CBC counts.
Dogs were housed in closed indoor/outdoor runs and were
exercised outdoors once daily for 2 hours. Housing and treatment
protocols adhered to European regulatory rules for animal welfare;
all experimental protocols complied with European Union guide-
lines on animal welfare and were approved by the Royal Canin
Committee for Animal Ethics and Welfare.

Diets

Three complete and balanced diets, purpose formulated for

weight loss in obese adult dogs, were used (Table 1). The diets
mainly differed in their protein and fiber content: the first diet was
high in protein and high in fiber (HPHF diet),

a

the second diet was

high in protein and contained a moderate amount of fiber (HP
diet),

b

whereas the third diet was high in fiber but contained

a moderate concentration of protein (HF diet)

c

(Table 2). Diets

were analyzed for ash, crude protein (calculated from Dumas
nitrogen values), and total lipid content by using the Association
Franc¸aise de Normalisation methods.

26

Total dietary fiber was

assayed by using methods that adhered to the Association of
Analytical Chemists guidelines,

27

whereas energy content was

measured by using an adiabatic bomb calorimeter.

d

Experimental Study Protocols to Test Satiety

Five sequential studies were performed where the dogs of the

different breeds consumed the 3 test foods based upon a Latin square
design. For all studies, the outcome measure of interest was the
amount of energy consumed (in kilocalories per kilogram metabolic
body weight [kg

0.73

]; kcal kg BW

0.73

) during a 15-minute period of ad

libitum access to food. However, in studies 1 to 4, the method by
which food was offered depended upon the breed: Shetland
Sheepdogs and Brittany Spaniels were offered an unlimited amount
of food for the 15-minute period; given the gluttonous nature of
Labrador Retrievers and to limit weight gain during the studies, the
amount of food offered at each meal corresponded to 60% of
maintenance energy requirements (MER), where MER 5 132 kcal/
kg

0.73

. At least 2 meals per day were given in all studies.

Study 1: Spontaneous Food Intake during the First Meal of

the Day. The first study assessed the spontaneous food intake of
each diet, for the first meal of the day, over a period of 10 days.
Dogs were fed 2 meals per day.

Table 1.

Composition of the diets used to determine satiety in dogs.

Diet

HPHF

HP

HF

ME content

a

2,900 kcal/kg

3,275 kcal/kg

2,660 kcal/kg

g/100 g

b

g/1,000 kcal

c

g/100 g

b

g/1,000 kcal

c

g/100 g

b

g/1,000 kcal

c

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

ingredients

Vegetable fibers, dehydrated poultry meat,

maize, wheat gluten, hydrolyzed animal
proteins, wheat, maize gluten, animal fats,
beet pulp, minerals (Cl, K, Na, Zn, Mn,
Fe, Cu, I), fish oil, L-tyrosine, FOS, soya
oil, psyllium husks and seeds, sodium
polyphosphate, green tea and grape
extracts, vitamins (choline, E, C, niacin,
B2, calcium pantothenate, B1, B6, A, folic
acid, biotin, B12, D3), hydrolyzed
crustaceans, taurine, marigold extract, L-
carnitine, hydrolyzed cartilage,
antioxidants (BHA, propyl gallate),
preservatives (potassium sorbate).

Dehydrated poultry meat,

wheat, maize gluten, cellulose,
beet pulp, poultry fat, poultry
liver hydrolysates, minerals
(Cl, Na, Ca, Zn, Mn, Fe, Cu, I,
Se), fish oil, psyllium, taurine,
vitamins (choline, E, C, niacin,
B2, calcium pantothenate, B1,
B6, A, folic acid, biotin, B12,
D3), antioxidants (BHA,
propyl gallate), preservatives
(potassium sorbate).

Ground maize, ground peanut hulls,

chicken and turkey meal, soybean meal,
maize gluten meal, digest, soybean
hulls, vegetable oil, cellulose, flaxseed,
salt, L-carnitine supplement, taurine,
minerals (potassium chloride, calcium
carbonate, zinc oxide, ferrous sulfate,
copper, manganese), vitamins (choline
chloride, D3, E, thiamine, niacin,
calcium panthotenate, pyridoxine,
riboflavin, folic acid, biotin, B12).
Contains EU approved antioxidants
(BHA, propyl gallate).

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.

1204

Weber et al

Study 2: Satiety during Repeated Short-Term Food Exposure.

The objective of this study was to assess the consumption kinetics
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

nonconsecutive days.

Study 3: Medium-Term Satiety Effect. This study assessed the

satiety effect of the 3 diets 3 hours after initial presentation of food.
On the study days, each animal was fed for 15 minutes at 8:00

AM

(t0), then for a further 15 minutes at 11:00

AM

(t3). This protocol

was applied for 2 consecutive days.

Study 4: Long-Term Satiety Effect. The objective of this study

was to assess the pattern of food intake when fed 2 meals per day,
mimicking a typical feeding pattern for many client-owned dogs.
On the study days, each animal was given food for 15 minutes at

8:00

AM

(t0) and at 3:00

PM

(t7). For each subject, this protocol was

applied twice for 3 consecutive days.

Study 5: Satiety Effect of an Energy-Restricted Meal. The final

satiety study evaluated the satiety effect of the diet when fed an
initial amount equivalent to the amount fed a weight-loss protocol
(eg, approximately 50% MER at target weight, divided over 2
meals). At 8:00

AM

(t0), each animal was given a meal of 25% of

daily MER. At 11:00

AM

(t3), Labrador Retrievers were fed 60% of

MER for 15 minutes, whereas Shetland Sheepdogs and Brittany
Spaniels were fed ad libitum at this time point. This protocol was
applied for 2 consecutive days.

Palatability Study

A panel of 105 dogs of different sizes participated in food

preference tests between the 3 study diets (HPHF, HP, and HF).
Two diets were compared on each study day, with each test day
being separated by a day. The order of the comparisons was not
randomized. For each test, the 2 diets were served, side-by-side, in 2
identical bowls. The amount provided in each bowl was equivalent
to twice the energy requirements recommended for each dog. At
the end of the 15-minute test period, the amount of each food
consumed by all dogs was measured. The ratio of consumption was
calculated by the following equation:

Ratio A (orB) (%)

~

consumption of food A (or B)

(consumption of food A z consumption of food B)

| 100

Protein and Dry Matter Digestibility

Digestibility Trials. Digestibility was assessed in the 3 diets over

5 days during satiety studies 3 and 4. Food was given twice daily
(at 8:00

AM

and 11:00

AM,

or 8:00

AM

and 3:00

PM

, depending on the

protocol) and water was available ad libitum. Feces were collected
and maintained at 4

uC over 5 days. At the end of each period, the

pooled wet feces were weighed, thoroughly mixed with an electric
blender, and aliquots of 100 g were frozen and stored (220

uC)

pending analyses.

Analysis. Dry matter (DM) content of food and feces was

determined after oven-drying to constant weight at 103

uC, whereas

crude protein was measured from Dumas nitrogen values.
Apparent digestibility percentage of DM and crude proteins was
then calculated by using the formula:

Apparent digestibility (%)

~

DM=protein intake

DM=protein in feces

DM=protein intake

| 100

Statistical Analysis

Statistical analysis was performed with a computer software

package.

e

Given that the main outcome of interest for weight-loss

programs is total amount energy consumed, all data are expressed
as energy intake (kilocalories) per kilogram metabolic body weight
(kg

0.73

). For the satiety studies, continuous data were first

confirmed to have a Gaussian distribution. A repeated-measures
design was used to assess effects of variables, including diet type,
timing of feeding, and individual variation on total energy
consumed. A Bonferroni procedure was used for post hoc analysis.
Satiety studies 2 through 5 were performed consecutively and each
study was performed twice; therefore, for statistical purposes, each
repeat constituted a repetition of the measure on the same

Table 2.

Energy intake (kcal/kg BW

0.73

) of 3 diets of

differing protein and fiber composition.

Satiety Trial

Mean

SD

1. Intake at first meal of day

HPHF

44

a

21.2

HP

69

20.4

HF

49

a

19.2

3. Medium-term satiety (0 hour and 3 hours)

HPHF t0

44

b

18.0

HPHF t3

27

c

22.2

HP t0

67

14.6

HP t3

57

18.8

HF t0

49

b

19.4

HF t3

41

6.8

4. Long-term satiety (0 hour and 7 hours)

HPHF t0

150

78.9

HPHF t7

147

83.1

HP t0

166

93.0

HP t7

165

94.5

HF t0

138

70.7

HF t7

109

50.9

5. Satiety after energy-restricted meal

d

HPHF t0

27

5.2

HPHF t3

31

23.3

HP t3

63

e,f

10.2

HF t0

24

4.0

HF t3

59

e,f

18

BW, body weight; SD, standard deviation; HPHF: High-protein

high-fiber diet; HP: high-protein diet; HF: high-fiber diet; t0, time
5

0 hours; t3, t 5 3 hours; t7, time 5 7 hours.

a

Energy intake significantly lower than energy intake on HP diet

(P , .05).

b

At t0, energy intake significantly lower than energy intake on

HP diet (P , .05).

c

At t3, energy intake significantly lower than intake on HP diet

(P 5 .024).

d

Restricted meal (25% of daily maintenance energy requirement)

fed at t0, ad lib at t3.

e

At t3, energy intake significantly greater than energy intake on

HPHF (P , .05).

f

At t3, energy intake significantly greater than for the same diet

at t0 (P , .05).

Satiety in Dogs

1205

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

Meal of the Day. On a twice-daily meal pattern, the
amount of food consumed during the first meal of the
day was significantly different among diets (HP 69 6
20.4 kcal/kg

0.73

versus HF 49 6 19.2 kcal/kg

0.73

versus

HPHF 44 6 21.2 kcal/kg

0.73

; P 5 .0057) (Table 2). There

was significantly greater energy consumption on the HP
diet compared with both the HPHF and HF diets (P 5
.0025 and P 5 .016, respectively). Energy consumption
on the HPHF and HF diets did not differ significantly
(P 5 .52).

Study 2: Satiety during Repeated Short-Term Food

Exposure. The second study assessed the short-term
satiety effect of diets offered for 15 minutes on 4
occasions over a 3-hour period (t0, t1, t2, t3). A
significant overall diet effect was noted (P 5 .038), but
post hoc testing did not identify significant differences
among individual time points.

There was a significant time trend evident for all

diets, with energy intake decreasing over the 3 meals
(Fig 1). Energy intake on the HPHF diet decreased by
49% between t0 and t1 (P 5 .036), and by 77% between
t1 and t2 (P 5 .047); the proportional decrease in energy
intake on the HP diet was 41% between t0 and t1 (P 5
.041), and 31% between t1 and t2 (P 5 .044); the
proportional decrease in the amount of HF diet
consumed was 28% between t0 and t1 (P 5 .027), and
33% between t1 and t2 (P 5 .045).

Study 3: Medium-Term Satiety Effect. There was

a significant diet effect on food intake (P 5 .0028), and
significantly less energy was consumed on the HPHF
than on the HP diet (P 5 .041) (Table 1).

Study 4: Long-Term Satiety Effect. When dogs were

offered food on a twice daily meal pattern (t0, t7), there
was no significant difference in energy intake between
the 2 meals for any diet (P 5 .19) (Table 2).

Study 5: Satiety Effect of an Energy-Restricted Meal.

Energy intake increased significantly between t0 and t3
for both the HF (146%, P , .001) and HP (75%, P ,
.001) diets but not for the HPHF diet (15%, P 5 .27).
Further, significantly less energy was consumed on the

HPHF diet at t3 than on either the HP (251%, P 5
.0051) or HF (247%, P 5 .014) diets. However, there
was no significant difference at t3 between the energy
intake on the HP and HF diets (7%, P 5 .37).

Palatability Study

A greater number of the 105 dogs preferred the

HPHF and HP diets to the HF diet (amount of food
consumed: 82% HPHF versus 18% HF diet, P , .001;
71% HP versus 29% HF diet, P , .001), but there was
no significant difference in preference between HPHF
and HP diets (amount of diet consumed 58% HPHF
versus 42% HF diet, P 5 .11).

Digestibility

DM digestibility of HPHF (61% 6 3.4%) was

significantly lower than that of HP (65% 6 3.0%, P 5
.009). However, no difference was observed between the
HF diet (62.5% 6 4.36%) and either the HPHF (P 5
.128) or HP (P 5 .074) diets. Protein digestibility was
significantly lower for the HF diet (78% 6 2.5%) than
for both the HPHF (81% 6 1.0%, P , .001) and HP
(81% 6 1.6%, P 5 .0025) diets.

Discussion

The current study assessed the effect of 3 diets on the

voluntary food intake in dogs. Overall, our results
indicated that a diet formulated to contain high contents
of both protein and fiber had a greater satiating effect
than did diets formulated to contain higher contents of
either protein or fiber alone. Given that excessive hunger

Figure 1.

Box plot of sequential energy intake on 3 diets (high

protein high fiber [HPHF], high protein [HP], and high fiber [HF])
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
(horizontal line) and interquartile range (top and bottom of box).
Energy intake decreased over the 4 meals for all diets, (P , .05),
with the HPHF diet having the greatest proportional decrease.
Further, at all meals, energy intake was lower on the HPHF diet
than the HP diet at all meals (P , .05). Energy consumption was
also lower on HPHF than HF at t2 and t3 (P , .05 for both).
Energy intake on HF was significantly lower than HP at t0 (P
5

.013).

1206

Weber et al

and begging behavior are common reasons for owners to
withdraw their dogs from weight-loss programs, im-
proved compliance would be expected. The fact that
none of the diets had a significant effect on intake over
the longer term (7 hours) could still mean that there
might be signs of hunger a number of hours after a meal.
Thus, additional feeding strategies, such as splitting
daily ration over a number of meals, might still be
necessary to maximize compliance with weight-reducing
diets.

Five associated studies were used to assess the dietary

effect on satiety. In all studies, the primary outcome
measure was energy consumption. Initially, voluntary
intake was assessed during the first meal of the day. The
second study assessed short-term satiety when providing
repeated exposure to food in a 3-hour period. The next 2
studies assessed satiety over the medium (3 hours) and
long (7 hours) term, whereas the final study assessed the
satiety effect after an energy-restricted meal (equivalent
to the approximate amount that would be fed during
a weight-loss program). Overall, the HPHF diet led to
the greatest reduction in voluntary energy intake during
the short and medium term, suggesting that it had the
greatest satiating effect. The comparative difference was
greater between HPHF and HP diets than between
HPHF and HF diets. Further, the HF diet had a superior
effect on satiety than the HP diet.

When taking these results together, it is tempting to

speculate that both fiber and protein are exerting
satiating effects but that the effect of fiber is greater
than that of protein. However, other effects may
explain the differences observed. First, the type of fiber
included in both of the fiber-supplemented diets is
different; fiber in the HF diet was mainly derived from
peanut hulls, soybean hulls, and cellulose; in the HPHF
and HP diets, cellulose, beet pulp, and psyllium husks
(HPHF only) were the main fiber sources. Different
types of fiber may exert differing effects on satiety.
Most notably, the results of many studies conducted on
humans showed that psyllium reduces caloric consump-
tion while improving satiety.

28–30

The action of psyllium

on caloric intake and satiety could result from its
capacity to increase chyme viscosity, which slows down
gastric emptying, as shown previously in humans

28

and

dogs.

31

To assess the relative effects of both fiber and

protein supplementation most appropriately, 4 similarly
formulated diets would have been needed, which only
differed in fiber and protein content (eg, HPHF, HP
only, HF only, and neither HP nor HF). A second
possibility for observed differences among diets is that
other nutrient concentrations may also have differed.
For example, the contents of fat included were 34 g/
1,000 kcal, 31 g/1,000 kcal, and 28 g/1,000 kcal for
HPHF, HP, and HF, respectively. However, although
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
more likely to be the result of protein and fiber than
fat. Therefore, although the current study design was
limited because not all other dietary factors were

standardized, it has the advantage that all of the
current diets are commercially available and thus is
reflective of their use in a clinical setting.

The final part of the satiety study demonstrated that

the HPHF diet had a satiating effect even when fed at an
energy-restricted level; the other main study limitation
was that satiety was not assessed in dogs on a weight-
reduction program. It is not known whether the
satiating effect wanes when a restricted diet is fed
continually, and this will require a future prospective
study. Nevertheless, the favorable satiety characteristics
of this current diet suggest it would likely perform better
than if using diets only formulated to be high in protein
or in fiber.

A major question in studies on appetite and satiety is

the method by which satiety is assessed. In humans, this
is easy and usually involves rating perception of satiety,
with a visual analog scale, after various meals are
consumed.

5

However, given that such data cannot be

collected in dogs, we chose to monitor voluntary food
intake as an indirect measure of satiety. Nevertheless,
such an assumption is only valid if there is no difference
in palatability among diets assessed. Significant differ-
ences in palatability were evident in this study, with the
HF diet the least palatable, and the HP and HPHF diets
were equivalent in palatability. Therefore, palatability is
unlikely to account for the observed differences in food
consumption observed, and, in fact, the improved satiety
effect of the HPHF diet over the HF diet may be more
pronounced given its superior palatability. Although
a study with diets of identical palatability would have
been a more scientific method of assessing the satiating
effects of protein and fiber, the use of commercially
available diets meant that the results of the current study
are more readily applied to the clinic.

One concern of using a diet high in fiber for weight

loss is the potential for reduced digestibility, particularly
with regard to protein, because high protein concentra-
tions in the diet are essential to minimize lean tissue
loss.

32,33

Although there was a significant decrease in

protein digestibility for the HF diet, no difference in
protein digestibility was noted for the HPHF diet. The
exact reason for this is not clear but may be the result of
high ileal digestibility of its protein and, therefore, its
low index for indigestible protein.

In conclusion, the current study demonstrated that

a HPHF diet led to improved satiety over diets that were
supplemented in either HF or HP. This novel approach
to tackling the problem of hunger may lead to greater
acceptance of conventional weight-loss programs in
companion animals. Further studies will be required to
confirm that the favorable characteristics noted in the
current study are maintained when the same diet is fed
during a long-term weight-reduction program.

Footnotes

a

Satiety Support diet, Royal Canin, Aimargues, France

b

Obesity Management diet, Royal Canin, Aimargues, France

Satiety in Dogs

1207

c

r/d; Hill’s Pet Nutrition Inc, Topeka, KS

d

C2000 basic adiabatic bomb calorimeter, IKA, WERKE, Staufen,
Germany

e

Statgraphics Plus 5.0, Manugistics Inc, MD

Acknowledgments

AJG’s senior lectureship is funded by Royal Canin.

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