the increasing prevalence of obesity represents a major public health concern in many countries , and healthy eating can play a predominant role in prevention strategies . in this context , it is important to identify effective nutritional strategies to help individuals achieve or maintain a healthy weight by making better food choices .
one of these strategies consists in the regulation of food labeling , which includes the use of nutrition claims intended to provide a quick and easy way to identify foods with nutritional features of interest [ 24 ] . in this
regard , satiating properties of foods induced by specific nutrients such as fibres or proteins are of particular interest [ 5 , 6 ] .
indeed , there is convincing evidence that appetite sensations are important determinants of long - term energy intake [ 7 , 8 ] and that satiety - enhancing foods may provide benefit to consumers by facilitating appetite control and compliance with weight - management efforts .
furthermore , the regulation of nutrition claims related to satiety is currently evaluated and developed by health organizations , which clearly recommend that such claims are supported by strong scientific evidence [ 10 , 11 ] .
while nutritional information related to the satiating effects of foods might be relevant for weight control , less is known about consumers ' perception and understanding of such nutrition claims and how these claims can affect perceived appetite sensations . indeed ,
nutritional information conveyed by food labeling can be difficult to understand for many consumers , particularly for older adults , adolescents , or those with less education [ 12 , 13 ] .
nutrition claims can also be misunderstood , which may lead to misleading inferences or unexpected eating behaviors .
for example , a recent study showed that a low - fat - labeled candy was perceived healthier than a regular - labeled candy , independent of caloric information .
healthy  was considered less fattening and that the amount eaten was 35% higher than when the snack was described as 
unhealthy  . with regard to appetite sensations , it has been demonstrated that a food considered as unhealthy is perceived to contribute more to weight gain and satiation , while imposed healthy eating can increase the sensation of hunger .
beliefs and expectations about the satiating power of a food can also affect perceived fullness , and this effect can persist as long as three hours after the meal .
another study showed that a meal presented as highly satiating , without having physiological satiating properties , can increase satiety potential more than a meal having physiological satiating properties , but presented as regular .
this suggests that the psychological effect of a satiety - related claim can be as effective as a physiological effect related to intrinsic satiety properties and highlights the need to better understand this possible psychological effect .
individual factors such as sex , weight , or restrained eating could also influence the perception of foods and modulate behavioral change .
as the perception of food can influence appetite sensations , it could be hypothesized that individual factors can also modulate the perception of appetite sensations .
since women generally consider themselves as being more knowledgeable about nutrition and having better eating habits   and tend to pay more attention to nutritional information , it could be suggested that women would be more readily influenced by nutrition claims .
overweight / obese individuals and restrained eaters might also be more sensitive to nutrition claims related to healthy eating or weight loss since they can use it as a tool for weight management .
interestingly , one study showed that food products carrying satiety - related claims were generally not seen as a magic bullet to weight loss , but that restrained eaters were more prone to overinterpretation of these claims , that is to interpret it as directly delivering weight loss .
individual factors can thus affect perception of foods and perceived appetite sensations , but they can also act in a physiological way . indeed ,
some studies have associated higher levels of restraint with an orexigenic hormonal profile [ 24 , 25 ] , suggesting that restrained individuals could more easily feel hunger .
it has also been proposed that overweight / obese individuals are less connected to their internal signals than normal - weight individuals , making the detection of hunger and satiation more complex .
sex , weight , and restrained eating are thus variables of interest when studying appetite sensations , alone or in combination with nutrition claims . in summary
, current literature suggests that nutrition claims may influence perception of foods and appetite sensations and that this influence could be modulated by individual factors such as sex , weight , or restrained eating . in that context
, there is an urgent need to better understand the way nutrition claims should be used , taking into account possible side effects , and evaluate the relevance of some claims in a public health nutrition context .
this study addresses this issue by evaluating combined and separated effects of nutrition claims and individual factors on appetite sensations .
the main purpose of this study was to evaluate the impact of nutrition claims and individual factors on perceived appetite sensations .
the specific objectives were ( 1 ) to evaluate the effects of  healthy ,   diet ,  or 
claims on appetite sensations , ( 2 ) to evaluate if sex , weight , or restrained eating influence appetite sensations , and ( 3 ) to investigate if sex , weight , and restrained eating can modulate the effects of nutrition claims on appetite sensations . note that the  hedonic 
condition refers to ingredients generally considered as highly palatable and that the  diet  condition refers to satiating properties ( see section 2.1 for a complete description ) .
our corresponding hypotheses are that ( 1 ) the snack in the  healthy  condition will be less satiating than in the  diet  or  hedonic  conditions , ( 2 ) individual factors such as sex , weight , and restrained eating will significantly influence appetite sensations , and ( 3 ) the satiating effects of the  diet  and  hedonic  conditions will be more important in overweight / obese restrained women .
the study was conducted among 164 men and 188 women ( aged 1865 ) from quebec city , canada , who were invited to taste and rate an oatmeal - raisin snack in a blinded and ad libitum context .
exclusion criteria were personal condition or history of diseases that could affect food intake ( unstable weight in the last two months , pregnancy , breastfeeding , eating disorders , type 1 or 2 diabetes , and uncontrolled hypo- or hyperthyroidism ) , use of medication that might interfere with appetite or food taste ( antidepressants , antipsychotic , or corticosteroids ) , and food allergies for safety reasons .
participants were randomly assigned to an experimental condition in a three (  healthy  versus  diet  versus  hedonic  ) by two ( restrained or not restrained ) by two ( normal - weight or overweight / obese ) by two ( men versus women ) factorial design , which means that the recruitment was based on these characteristics in order to obtain a balanced number of participants in each subgroup .
this design results in eight subgroups based on individual characteristics combined with the three experimental conditions tested , which leads to a total of 24 combinations for the analysis . the factorial distribution of participants is presented in table 1 .
initial randomization was performed according to self - reported weight and height and restraint score , but participants were reassigned according to their measured data if needed .
condition emphasized the favorable nutritional characteristics of the snack :  the snack product that you have to taste today is a new high - fiber oatmeal snack made with healthy ingredients .
you have certainly heard that whole oatmeal is good for your health because it contains soluble fibers .
so , this new oatmeal snack is high in soluble fibers , as well as low in saturated fat and free from trans - fat .
 the  diet  condition focused more on beneficial satiating properties for weight management :  the food product that you have to taste today is a new healthy high - fiber snack .
you must have probably heard that whole - grain foods , like those that contain oat soluble fibers , are composed of complex carbohydrates which are digested slowly and which can delay the appearance of hunger .
this new healthy snack has been especially designed to satiate , because it is a source of fibers , which make it an interesting choice for any persons concerned to reach and to maintain a healthy weight .  finally ,
condition underlined the sweet and pleasant taste of the snack using hedonic food words : 
( these are ) new gourmet cookies made with fresh butter and old - fashioned brown sugar .
so , these new cookies are a great treat with a pleasant , sweet taste .
cookie  was never mentioned in the two first conditions , and that we specifically chose to use an oatmeal - raisin rather than a chocolate snack in order to facilitate the blinded context of the experiment , as oatmeal and raisins can be considered as healthy ingredients or not depending on the food containing it .
indeed , this psychological manipulation was previously shown to be effective in changing the healthiness perception of food [ 16 , 28 ] . in spite of the description ,
the study was approved by the institutional review board of universit laval ( # 2009 - 117/26 - 05 - 2009 ) and was registered in the clinical-trials.gov registry ( nct01141140 ) .
participants came to the institute of nutrition and functional foods ( universit laval ) between 8:30 a.m. and 7 p.m. at a single occasion .
they had to be in a fasting state for at least two hours prior to their visit .
they were given a food description according to the experimental condition they were assigned and then had 10 minutes to taste the snack ad libitum in a private room .
participants stayed for approximately two hours after the taste - rating task to complete appetite sensations scales , questionnaires , and anthropometric measurements .
they were told the real goal of the study only at the end of the visit and were free to withdraw their participation at that moment .
appetite sensations are defined as follows : hunger refers to the physiological recognition of a need to eat , while desire to eat reflects the motivation to eat , fullness is a physical feeling that could be related to the degree of stomach filling , and satiety refers to the processes that inhibit further intake after an eating occasion has ended .
appetite sensations were evaluated with unipolar 150  mm visual analog scales ( vas ) ( adapted from hill and blundell ) .
these scales are anchored at the two ends with the extremes of the subjective feeling evaluated .
vas have been widely used in the past to evaluate appetite sensations and are considered reliable for single meal protocols [ 31 , 33 ] .
participants rated their appetite sensations before the test meal ( time = 10 ) as well as immediately after ( time = 0 ) and 20 , 40 , and 60 minutes later . the first measure ( time = 10 ) was taken immediately before the description of the snack .
four appetite sensations were measured : desire to eat (  how strong is your desire to eat ?  ;  very low desire  to  very high desire  ) , hunger (  how hungry do you feel ?  ;  not at all hungry  to  extremely hungry  ) , fullness (  how full do you feel ?  ;  not at all full  to  extremely full  ) , and prospective food consumption ( pfc ) (  how much food do you think you could eat ?  ;  none at all  to  a large amount  ) .
the vas values were calculated by measuring the distance in mm with a ruler from the left end of the scale to the mark drawn by the participant with a precision of 0.5  mm .
one - hour area under the curve ( auc ) was calculated from time zero to time 60 with the trapezoid method . as recommended by blundell et al .
the auc allows an overall view of the appetite sensation response , while the raw vas data allows comparisons at each time .
appreciation of the snack (  in general , how much do you appreciate the food you just tasted ?
 ) was evaluated with a unipolar 150  mm vas labeled from bottom to top with  not at all ,   moderately ,  and  enormously .  a validated food frequency questionnaire ( ffq )
the restraint scale allowed the distinction between restrained eaters ( score  12 for men and  15 for women ) and unrestrained eaters ( score < 12 for men and < 15 for women ) .
the validity of the restraint scale for the measurement of restrained eating has been previously reported [ 3739 ] .
the food pleasure scale ( fps ) was also used to evaluate the pleasure associated with eating .
body mass index ( bmi ) was calculated from weight and height measured after the completion of all questionnaires .
participants were classified as normal - weight if they had a bmi under or equal to 25  kg / m and as overweight / obese if they had a bmi higher than 25  kg / m .
energy needs were estimated from the mean of ffq data and the harris - benedict formula , as previously performed in our research institute . with a mean cohen 's d estimate of 0.35 ,
power analyses for anovas testing main effects and interactions indicated that a sample size of 180 males and 180 females would allow the detection of significant differences with an alpha level of 0.02 and a power ( 1   error probability ) of 0.90 .
one - way analyses of variance ( anovas ) were used to assess differences in initial characteristics between experimental conditions . in line with the factorial design of the study , factorial repeated measures anovas were performed with mixed procedures for the analysis of the appetite vas ( desire to eat , hunger , fullness , and pfc ) , with time , experimental condition , sex , bmi , and restrained eating used as independent variables and tested in interactions .
age and initial appetite sensations ( time = 10 ) were included in the models as potential confounding factors , as they may affect appetite sensations [ 29 , 44 ] .
adjustments for energy needs and total amount eaten were also made to palliate to the fact that the amount eaten was ad libitum and therefore not adjusted for energy requirements ( as the study also aimed to measure the effect of claims on food intake ) .
time of the day was also added as a covariate in case the two hours fasting period was not long enough to standardize initial appetite sensations .
finally , appreciation of the snack and pleasure associated with eating were added as covariates as hedonic eating indicators .
similar procedures without repeated measures were used for the analysis of auc for all appetite sensations .
the slice option was used to investigate significant experimental conditions effects in each of the eight predetermined subgroups ( based on sex , weight , and restrained eating ) .
the structure of covariance matrix was taken into consideration for all statistical models to ensure an optimal fit to the data .
a p value < 0.05 was considered statistically significant for all tests , with bonferroni corrections made for all multiple comparisons .
all analyses were performed with statistical analysis software version 9.3 ( sas institute , cary , nc , usa ) .
a total of 352 participants were recruited and completed the study . from these participants , 11 ( 4 men and 7 women ) were excluded from the analysis because of missing values in covariates .
the remaining total of 341 participants ( 160 men and 181 women ) were thus included in the present study .
one missing value was also observed for the initial pfc sensation ( time = 10 ) , which led to the exclusion of one participant from the pfc analysis because of the necessity of this covariate in the statistical model .
no significant differences were found between conditions for any initial characteristic . as explained previously in section 2.6 ,
all the following results are adjusted for age , time of the day , energy needs , amount eaten , and initial appetite sensations .
note that only initial appetite sensations and total amount eaten contributed significantly to the models .
no main experimental condition effect was observed for any of the four appetite sensations evaluated , when expressed in both vas means ( f(2,306 ) = 1.14 for desire to eat , f(2,306 ) = 1.54 for hunger , f(2,306 ) = 0.66 for fullness , and f(2,305 ) = 0.68 for pfc ; p = 1.00 ) and auc ( f(2,306 ) = 2.99 for desire to eat , f(2,306 ) = 3.20 for hunger , f(2,306 ) = 1.06 for fullness , and f(2,301 ) = 0.4440 for pfc ; p = 1.00 ) .
mean values for all vas at each time point ( 10 , 0 , 20 , 40 , and 60 minutes ) as well as their related auc are presented in table 3 for each experimental condition .
appetite sensations were affected neither by bmi ( p = 1.00 for all vas values and auc ) , nor by restrained eating ( p > 0.96 and p > 0.33 for all vas values and auc , resp . ) .
however , a main effect of sex was noted for all appetite sensations , with men reporting higher vas values than women for desire to eat , hunger , and pfc ( p < 0.004 ) and lower vas values than women for fullness ( p = 0.008 ) . as presented in table 4 ,
cohen 's d effect sizes ( ess ) ranged from 0.08 to 0.52 , which represents small to moderate effects .
an effect size comprised between 0.2 and 0.49 represents a small effect size , between 0.5 and 0.79 , a moderate effect size , and  0.8 a large effect size .
no sex differences were observed for desire to eat and hunger at baseline , but fullness was higher and pfc lower in women in comparison to men .
note that men had significantly higher energy needs and ate significantly more than women ( data not shown ) .
as previously explained in section 2.6 , adjustments were made for these covariates for all results presented .
significant effects of nutrition claims on appetite sensations were observed in specific subgroups ( based on combinations of individual factors ) . among normal - weight unrestrained women , lower auc values for desire to eat ( es = 0.76 ) ,
hunger ( es = 1.03 ) , and pfc ( es = 0.72 ) were observed in the  diet  condition compared with the  healthy  condition ( table 5 ) .
however , significant differences between these two conditions were not observed at each time point . some differences between  diet
 and  hedonic  conditions and also between  healthy  and  hedonic  conditions were also noted among normal - weight unrestrained women .
in fact , hunger was lower in the  diet  condition than in the  hedonic  condition at time 0 and was higher in the  healthy  condition than in the  hedonic  condition at time 20 ( table 5 ) . among overweight / obese unrestrained men , a higher auc value for fullness
was observed in the  diet  condition than in the  healthy  and  hedonic  conditions ( ess of 1.19 and 0.99 , resp . ) ( table 6 ) .
no significant differences were found between other subgroups for any of the four appetite sensations .
the aim of this study was to evaluate the impact of food labeling and individual factors on perceived appetite sensations and more precisely to ( 1 ) evaluate the effects of  healthy ,   diet ,  or 
claims on appetite sensations , ( 2 ) evaluate if sex , weight , or restrained eating influence appetite sensations , and ( 3 ) investigate if sex , weight , and restrained eating can modulate the effects of nutrition claims on appetite sensations . associated results are that ( 1 ) claims did not affect appetite sensations , ( 2 ) sex had a significant influence on appetite sensations , but not weight and restrained eating , and ( 3 ) a significant interaction between claims and individual factors has been observed in normal - weight unrestrained women and overweight / obese unrestrained men .
as previously reported , the psychological manipulation was effective in changing the  healthy  perception of the snack , as the  healthy  condition was considered to be healthier than the  diet  condition , itself considered healthier than the 
contrary to our first hypothesis , the three experimental conditions resulted in similar perceived appetite sensations , suggesting that a snack labeled with healthy characteristics is not necessarily perceived as less satiating than a snack labeled with satiating or hedonic properties .
this finding is in contradiction with finkelstein and fishbach   who demonstrated that participants felt hungrier after eating a 
healthy  chocolate - raspberry bar than after eating the same bar described as  yummy .
 however , few details are given in this study about the composition of experimental groups , and initial hunger sensation was not measured and then not used as a covariate , as performed in the present study . as our statistical models showed that initial sensations are important covariates to consider in the evaluation of appetite sensations , differences in statistical adjustments between studies may explain the different results obtained .
our finding is also in contradiction with arguin et al .   who demonstrated that highlighting the satiating properties of a meal increases satiety potential against a control condition .
the different types of food ( i.e. , snack versus meal ) used and the absence of a control condition ( i.e. , without any description ) in our study may explain why we did not observe such a difference .
it could also be explained by the fact that our  diet  condition was not only targeting satiating properties , but also weight control . as we did not measure the expected satiating power ( as performed previously for perceived healthiness )
in any case , the absence of an effect of nutrition claims on appetite sensations in our study implies neither a contraindication nor incentive to their use in a public health context . as hypothesized , sex had a significant influence on the perception of appetite sensations , regardless of nutrition claims , energy needs , and amount eaten ( men had significantly higher energy needs and ate significantly more than women ) .
indeed , men reported higher levels of desire to eat , hunger , and pfc and lower levels of fullness .
these results suggest that women could feel more easily satiated than men and could be less tempted to prospectively eat more food .
some studies have already reported similar findings [ 7 , 44 ] , while other studies found no sex differences   or mixed results depending on the appetite sensation observed and experimental conditions ( ad libitum versus controlled ) .
the fact that baseline fullness and pfc were , respectively , higher and lower in women than in men is also of interest .
it suggests that these two sensations could differ between men and women even before food consumption .
sex differences in the perception of appetite sensations could be explained by differences in hormonal profiles .
these observations involve that public health nutrition interventions may not have the same effects in men and women and that individual or group interventions should be adapted in consequence . according to our findings
, women could be more responsive to an intuitive or mindful eating approach than men , that is , to eat in response to physical sensations such as hunger and satiety signals [ 4951 ] .
health at every size ( haes ) programs , endorsed by the association for size diversity and health , are an example of interventions addressing the recognition of appetite sensations . 
other programs are also sex - specific , focusing more on body image for women and energy and body functions for men .
current literature shows that obese individuals have lower fasting ghrelin levels and that their ghrelin response to food intake is less pronounced than in normal - weight individuals .
this is in line with the proposition that overweight or obese individuals could be less sensitive to their internal appetite sensations .
however , we found no difference between normal - weight and overweight / obese individuals , which has been found in past literature .
another study proposes that hormonal response to food intake could be dependent of a bmi by sex interaction , suggesting that the study of bmi alone is not sufficient .
appetite - regulating hormones are not necessarily related to subjective appetite sensations , which could explain why we obtained different results as we only measured perceived appetite sensations and not appetite - regulating hormones .
also , we did not differentiate between overweight and obese individuals , our sample including more overweight ( n = 124 ) than obese ( n = 51 ) individuals . no main effect of restraint status on appetite sensations was observed .
this was unexpected as restrained eating has been previously associated with higher levels of perceived hunger .
it has also been already associated with higher levels of ghrelin [ 24 , 57 ] .
hooper et al .   also demonstrated that a high degree of weight cycling was associated with an appetite - stimulating hormonal profile .
as mentioned previously , however , appetite - regulating hormones are not necessarily well related to subjective appetite sensations . on the other hand , other studies found no effect of restrained eating on hunger [ 44 , 55 ] .
restrained eating can be measured either by the restraint scale ( as performed in the present study ) or by the restraint scales included in the three - factor eating questionnaire ( tfeq )   or the dutch eating behavior questionnaire ( debq ) .
the restraint scale combines the measure of concern with dieting and weight fluctuation , whereas both tfeq and debq measure attempt to restrict eating , independent of weight fluctuation .
the choice of the questionnaire used to classify participants as restrained or not could then explain differences in results obtained between studies . as proposed earlier , it is also possible that restrained eating needs to be considered in interaction with sex or bmi to reveal significant effects .
for example , martins et al .   showed that restrained eating in women could be associated with lower levels of hunger and higher levels of fullness .
even if weight status and restrained eating are important factors to consider in individual consultation , our results suggest that they do not necessarily need to be taken into account for the evaluation of appetite sensations . to our knowledge , this is the first study to explore the influence of nutrition claims on appetite sensations according to a combination of individual factors , namely , sex , weight , and restrained eating .
our hypothesis that overweight / obese restrained women would be more easily satiated in the  diet  and  hedonic  conditions in comparison with the  healthy  condition was not confirmed as a satiating effect of the  diet  condition was rather observed in normal - weight unrestrained women and overweight / obese unrestrained men , while no satiating effect of the  hedonic  condition was noted .
being more easily influenced by satiety - related claims could either indicate a greater susceptibility to external factors , or in contrary a better predisposition for the recognition of internal satiety signals .
an effect of nutrition claims was only noticed in individuals presenting a low level of cognitive restraint , which has already been associated with a lower susceptibility to external influences [ 20 , 56 ] . it is then more likely that the  diet
this observation highlights the relevance of considering individual factors in interaction when studying appetite sensations .
our results also suggest that nutrition claims emphasizing satiating properties could be more effective in reducing perceived hunger than claims focusing on hedonic properties .
more precisely , it suggests a potential benefit of satiety - related claims , at least in certain subgroups of individuals .
first , it might be argued that the  healthy  and  diet  labels were not congruent with the food tasted , which could explain the absence of a main effect on appetite sensations .
however , this argument is not supported as the manipulation effectively changed the perception of food . on the other hand ,
no control condition ( i.e. , without any description ) was used , and the  diet  condition was not only targeting satiating properties but also weight management .
also , the amount eaten was not standardized , which however allowed participants to eat according to their physiological and psychological needs .
the use of many multiple comparisons and bonferroni corrections could have led to a lack of power , but it can also be argued that the probability of committing type 1 errors is really small .
this study also has strengths , such as a high number of participants recruited on the basis of a factorial design .
this is also the first study to evaluate the role played by specific combinations of individual factors in the study of the effect of nutrition claims on appetite sensations .
we investigated the impact of nutrition claims and individual factors on the perception of appetite sensations .
women felt more satiated then men regardless of nutrition claims , while bmi and restrained eating alone did not influence appetite sensations .
no adverse effect of nutrition claims on appetite sensations was observed , which suggests no contraindication to their use .
positive effects of satiety - related claims have been observed only in specific subgroups of individual . in a real - world setting , foods labeled with satiety - related claims would possess demonstrated physiological satiating properties and therefore would probably induce a physiological effect ( as opposed to a psychological effect in this study ) . as enhanced satiety may benefit dietary control or weight - management , it may thus be useful to inform consumers about these specific properties . to conclude , nutrition claims do not generally affect appetite sensations and the evaluation of their relevance
sex is an important individual factor to consider when studying appetite sensations , while weight and restrained eating should be considered in interaction for a better understanding of their effects .
more studies are needed to assess a significant and beneficial effect of nutrition claims on appetite sensations and eating behavior , and to better understand the contribution of individual factors .
 nutrition claims may help people to adopt healthier eating habits , but little is known about the potential cognitive effects of such claims on appetite sensations . 
 the main purpose of this study was to evaluate the impact of nutrition claims and individual factors on perceived appetite sensations . according to a three (  healthy  versus  diet  
 ( i.e. , satiating ) versus  hedonic  ) by two ( restrained or not restrained ) by two ( normal - weight or overweight / obese ) by two ( men versus women ) factorial design , 164 males and 188 females aged 1865 were invited to taste an oatmeal - raisin snack in a blinded and ad libitum context . 
 visual analog scales ( 150  mm ) were used to evaluate appetite sensations before and over 1  h after consumption period . 
 bmi and restraint scale were used to categorize participants according to their weight and restraint status . 
 no main condition effect was observed for any of the four appetite sensations . 
 however , subgroups analysis revealed significant differences among specific subgroups . 
 a main effect of sex was also observed for all appetite sensations with men reporting higher levels of desire to eat , hunger and prospective food consumption , and lower levels of fullness than women . 
 these findings highlight the importance of considering individual characteristics in interaction when studying appetite sensations . 