Reevaluating cases of trait-dependent diversification in primates.

OBJECTIVES: Previous investigations have identified several ecological traits that may have shaped differences in species richness among primate clades by influencing speciation and extinction probabilities. In this study, I reevaluate these cases in light of concerns about high false-positive rates of the methods used to detect trait-dependent diversification. MATERIALS AND METHODS: Data for six traits were taken from the literature: activity pattern, sociality, mating system, terrestriality, frugivory, and mutualistic interactions with angiosperms (i.e., seed dispersal and pollination). These traits were treated as binary variables and analyzed in a phylogenetic framework using likelihood-based and nonparametric methods for estimating trait-specific diversification rates. RESULTS: Of the traits analyzed here, only activity pattern was found by all methods to be correlated with diversification: diurnal primates diversify at higher rates than nocturnal primates. Solitary foragers have a lower rate of diversification than group-living primates, but this link is driven by the association between solitariness and nocturnality. DISCUSSION: These results indicate that ecological traits have had a more limited influence on primate diversification than suggested by previous studies. The false positives detected here can be linked with heterogeneity in diversification caused by sources other than the focal traits. One of these sources is the very high rate of diversification in Cercopithecoidea found in previous investigations. Another is the correlation between activity patterns and diversification. The underlying causal mechanism for the contrast in diversification dynamics between diurnal and nocturnal primates is unclear, but this correlation highlights the important role of activity pattern in shaping primate evolutionary history.

Food group consumption in an Italian population using the updated food classification system FoodEx2: Results from the Italian Nutrition & HEalth Survey (INHES) study.

BACKGROUND AND AIM: Dietary habits evolve over time, being influenced by many factors and complex interactions. This work aimed at evaluating the updated information on food group consumption in Italy. METHODS AND RESULTS: A total of 8944 (4768 women and 4176 men) participants aged >18 years from all over Italy recruited in 2010-13 (Italian Nutrition & HEalth Survey, INHES) was analyzed. The recruitment was performed using computer-assisted-telephone-interviewing and one-day 24-h dietary recall retrieved from all participants. The updated, second version, of FoodEx2 food classification system was applied to extract data on food group consumption. The participation rate was 53%; 6.2% of the participants declared to follow a special diet, the most prevalent being hypo-caloric diets (55.7% of special diets). Men compared to women presented significantly higher intakes of "grains and grain-based products", "meat and meat products", "animal and vegetable fats and oils and primary derivatives" and "alcoholic beverages" (P for all<0.001); moreover, men had lower intakes of "milk and dairy products", "water and water-based beverages" and "products for non-standard diets, food imitates and food supplements" (P for all<0.001). Differences in food group intake among age groups, geographical regions and educational level groups were also identified (P for all<0.05). CONCLUSIONS: Data on the consumption of more than 70 food groups and sub-groups were illustrated in different strata. The present analysis could be considered as an updated source of information for future nutrition research in Italy and in the EU.

Integrating feeding behavior, ecological data, and DNA barcoding to identify developmental differences in invertebrate foraging strategies in wild white-faced capuchins (Cebus capucinus).

OBJECTIVES: Invertebrate foraging strategies in nonhuman primates often require complex extractive foraging or prey detection techniques. As these skills take time to master, juveniles may have reduced foraging efficiency or concentrate their foraging efforts on easier to acquire prey than adults. MATERIALS AND METHODS: We use DNA barcoding, behavioral observations, and ecological data to assess age-based differences in invertebrate prey foraging strategies in a group of white-faced capuchins (Cebus capucinus) in northeastern Costa Rica. Invertebrate availability was monitored using canopy traps and sweep netting. Fecal samples were collected from adult female, adult male, and juvenile white-faced capuchins (n = 225). COI mtDNA sequences were compared with known sequences in GenBank and the Barcode of Life Database. RESULTS: Frequencies of Lepidoptera and Hymenoptera consumption were higher in juveniles than in adults. A significantly smaller proportion of juvenile fecal samples contained Gryllidae and Cercopidae sequences, compared with adults (0% and 4.2% vs. 4.6% and 12.5%), and a significantly larger proportion contained Tenthredinidae, Culicidae, and Crambidae (5.6%, 9.7%, and 5.6% vs. 1.3%, 0.7%, and 1.3%). Juveniles spent significantly more time feeding and foraging than adults, and focused their foraging efforts on prey that require different skills to capture or extract. Arthropod availability was not correlated with foraging efficiency, and the rate of consumption of specific orders of invertebrates was not correlated with the availability of those same taxa. DISCUSSION: Our data support the hypothesis that juveniles are concentrating their foraging efforts on different prey than adults, potentially focusing their foraging efforts on more easily acquired types of prey.

Roots rather than shoot residues drive soil arthropod communities of arable fields.

Soil food webs are driven by plant-derived carbon (C) entering the soil belowground as rhizodeposits or aboveground via leaf litter, with recent research pointing to a higher importance of the former for driving forest soil food webs. Using natural abundance stable isotopes of wheat (C3 plant) and maize (C4 plant), we followed and quantified the incorporation of shoot residue- and root-derived maize C into the soil animal food web of an arable field for 1 year, thereby disentangling the importance of shoot residue- versus root-derived resources for arable soil food webs. On average, shoot residue-derived resources only contributed less than 12% to soil arthropod body C, while incorporation of root-derived resources averaged 26% after 2 months of maize crop and increased to 32% after 1 year. However, incorporation of root-derived maize C did not consistently increase with time: rather, it increased, decreased or remained constant depending on species. Further, preference of shoot residue- or root-derived resources was also species-specific with about half the species incorporating mainly root-derived C, while only a few species preferentially incorporated shoot residue-derived C, and about 40% incorporated both shoot residue- as well as root-derived C. The results highlight the predominant importance of root-derived resources for arable soil food webs and suggest that shoot residues only form an additional resource of minor importance. Variation in the use of plant-derived C between soil arthropod species suggests that the flux of C through soil food webs of arable systems can only be disentangled by adopting a species-specific approach.

In Vivo Pattern Classification of Ingestive Behavior in Ruminants Using FBG Sensors and Machine Learning.

Pattern classification of ingestive behavior in grazing animals has extreme importance in studies related to animal nutrition, growth and health. In this paper, a system to classify chewing patterns of ruminants in in vivo experiments is developed. The proposal is based on data collected by optical fiber Bragg grating sensors (FBG) that are processed by machine learning techniques. The FBG sensors measure the biomechanical strain during jaw movements, and a decision tree is responsible for the classification of the associated chewing pattern. In this study, patterns associated with food intake of dietary supplement, hay and ryegrass were considered. Additionally, two other important events for ingestive behavior were monitored: rumination and idleness. Experimental results show that the proposed approach for pattern classification is capable of differentiating the five patterns involved in the chewing process with an overall accuracy of 94%.

Habitual eating of breakfast, consumption frequency of selected food and overweight prevalence in adolescents from various age groups.

AIM: To assess the influence of eating breakfast on the consumption of selected food and overweight prevalence among adolescents from different age groups. MATERIAL AND METHODS: The study group consisted of students aged 13-18.9 (n=1700). Their height and weight measurements were used to calculate their body mass index and interpreted according to international standards for adolescents. Food consumption was assessed via the frequency method and involved the consumption of breakfast, dietary "bre and sweetened beverages. We used Block's validated questionnaire to assess the intake of dietary "bre and its sources. Analysis of the results was carried out in three age groups: 13-14.9, 15-16.9 and 17-18.9 years old. We used one-factor logistic regression adjusted by gender. RESULTS: The percentage of adolescents with a regular habit of eating breakfast dropped by 5.7 percentage points when compared to adolescents aged 13-14.9 and 17-18.9 (from 54.2% to 48.5%), which was a phenomenon accompanied by an increase in the percentage of adolescents who ate breakfast irregularly or hardly ever (by 3.7 and 1.9 percentage points, respectively). Eating breakfast infrequently was related to a more frequent consumption of sweetened beverages (the odds ratio: from 2.32 to 2.67 depending on the age group) and a higher prevalence of a "bre-poor diet (from 1.49 to 2.23). Among adolescents aged 13-14.9 who hardly ever ate breakfast, the chance of being overweight increased by 83% in comparison to adolescents with regular habits of eating breakfast. CONCLUSIONS: The frequency of eating breakfast decreased with the adolescents' age, especially among girls. Eating breakfast infrequently was associated with unhealthy nutrition, typical examples of which are lower intake of dietary "bre and more frequent consumption of sweetened beverages, and in the youngest group of adolescents caused a higher prevalence of overweight.

A preliminary investigation into diet adequacy in senior residents of Newfoundland and Labrador, Canada: a cross-sectional study.

BACKGROUND: Adequate dietary intake is essential to maintain good health. This is particularly true for the elderly. This study investigated the dietary intakes of seniors residing in Newfoundland and Labrador (NL) and assessed the adequacy of nutrients which they consumed as food. METHODS: Between November 2012 and January 2013, we recruited senior residents in NL, aged 65 years or older Participants were required to complete two questionnaires, one food-frequency questionnaire (FFQ) and one general health questionnaire (GHQ). Macro- and micro- nutrients in foods consumed were estimated using the Elizabeth Stewart Hands and Associations (ESHA) nutrient analysis software. The nutrient intakes were compared with appropriate components of the dietary reference intakes (DRIs) adopted by Health Canada to determine adequacy. Various descriptive statistical analyses were performed using SPSS. RESULTS: One hundred-and-eleven participants (69 females and 42 males) completed the surveys and were included in the analysis. A considerable portion of subjects were overweight (41.7%) or obese (25%), and had at least one chronic illness (86.5%). Many seniors studied did not meet the daily recommendations for dietary intakes of nutrients supported by Health Canada, notably vitamin E (84.7%) and vitamin D (68.5%). Our study also suggests that about 40% of participants consumed more dietary energy as fat than is recommended. CONCLUSION: The present study revealed an inadequate consumption of essential nutrients from foods in a noninstitutionalized senior population of NL.

Diet and niche breadth and overlap in fish communities within the area affected by an Amazonian reservoir (Amapá, Brazil).

We investigated the niche breadth and overlap of the fish species occurring in four environments affected by the Coaracy Nunes reservoir, in the Amapá Brazilian State. Seasonal samples of fishes were taken using a standard configuration of gillnets, as well as dragnets, lines, and cast-nets. Five hundred and forty stomach contents, representing 47 fish species were analyzed and quantified. Niche breadth and overlap were estimated using indexes of Levins and Pianka, respectively, while interspecific competition was evaluated using a null model (RA3). ANOVA and the Kruskal-Wallis test were used, respectively, to evaluate differences in niche breadth and overlap between areas. The data indicate that the majority of the fish species belong to the piscivore, omnivore, and detritivore guilds. These species have likely colonized the environments due to the availability of suitable feeding resources, and the favorable physical conditions created by the river damming. Overall, few species have ample niches, but most of them are highly specialized. Resources seasonal variation had little effect on the feeding behavior of most species in the study areas. The null models indicated that competition was not a factor determining on community structure.

Eating and rumination behaviour of Scottish Highland cattle on pasture and in loose housing during the winter.

This study examined eating and rumination behaviour in 13 Scottish Highland cattle for 13 days on a winter pasture and then for 13 days in a loose housing barn during winter. The cows were fed hay ad libitum and each was fitted with a pressure-sensitive transducer integrated into the noseband of the halter. The endpoints for each cow at both locations were calculated per day and included eating and rumination times, number of chewing cycles related to eating and rumination, number of regurgitated cuds and number of chewing cycles per cud. Air temperature, wind speed, relative humidity, barometric pressure and precipitation were recorded. Pastured cows had significantly longer eating and rumination times, more chewing cycles related to eating and rumination, more regurgitated cuds and more chewing cycles per cud than housed cows. Meteorological conditions were very similar at both locations.

Dans le présent travail, on étudie l'alimentation et la rumination de vaches Highland dans des conditions hivernales. Les vaches ont tout d'abord été détenues à l'extérieur durant 13 jours puis durant 13 jours également dans une stabulation ouverte; du foin était dans les deux cas affouragé ad libitum. L'enregistrement de l'alimentation et de la rumination était effectué au moyen d'un détecteur de pression intégré à la muserole du licol. On a analysé pour chaque animal et dans les deux endroits la durée journalière d'alimentation et de rumination, le nombre de mouvement de mastication lors de l'alimentation et de la rumination, le nombre de boli ruminatoires et le nombre de mouvement de mastication par bolus. On a également enregistré la température de l'air, la vitesse du vent, l'humidité relative, la pression atmosphérique et les précipitations. Dans la garde à l'extérieur, les durées d'alimentation et de rumination, le nombre de mouvements masticatoires, le nombre de boli ruminatoires et le nombre de mouvement masticatoire par bolus étaient tous significativement plus longs respectivement plus grands que lors de la garde en écurie ouverte. Les conditions climatiques étaient très similaires aux deux endroits.

Influence of diet on oral health in young adults--pilot study.

INTRODUCTION: Diet is a factor that can modify, among others, the course of caries, dental erosive lesions and periodontal disease. It is important to know the influence of diet on the clinical oral condition in young adults. MATERIAL AND METHODS: 20 women and 20 men aged 19-21 participated in the study. During a clinical examination of the patients the following clinical indices were estimated: Ap- proximal Plaque Index (API), Bleeding on Probing (BOP) and DMFT indices. The frequency and quality of food products consumed were noted in a special questionnaire. Results with p ≤ 0.05 were considered statistically significant. RESULTS: The average API value for the female participants was 77.37%, BOP--23.84% and DMFT--9.9. The t-test results for independent samples showed that women who consumed meat and meat products two times a week or more, had statistically higher API (p = 0.01) and BOP (p = 0.05) values, than the mean value for these indexes. Women who consumed grain products and grain-based products two times a week or more, had higher API values compared to the mean value for this index (p = 0.02). The average API value for the male participants was 34.25%, BOP--10.15% and DMFT--9.05, respectively. Men who consumed milk and dairy products three times a week or less had statistically lower API (p = 0.05) and BOP values (p = 0.02), relative to the mean index values. CONCLUSIONS: The chemical composition and texture of the food intake can affect oral health. Besides instruction in oral hygiene, doctors and dentists should also assess the eating habits of their patients.

Comparing diabetic with non-diabetic overweight subjects through assessing dietary intakes and key parameters of blood biochemistry and haematology.

INTRODUCTION: An important way of preventing type 2 diabetes is by adopting a proper diet by which means appropriate control over blood glycaemia and lipids can be achieved. OBJECTIVES: To assess selected biochemical and haematological markers in overweight subjects or those suffering from type 2 diabetes in relation to their estimated dietary intake. MATERIAL AND METHODS: The study was conducted in 2012 on n = 86 overweight or obese subjects living in Warsaw or its environs, of whom n = 43 had type 2 diabetes. Dietary intakes were compared between non-diabetics (control group) and diabetics (test group) by 3 day records, whilst the relevant blood biochemistry and haematology results were obtained from medical records; with patient consent. RESULTS: Diabetic subjects had significantly higher serum glucose and CRP levels than controls, respectively; 190 vs 98 mg/ dl and 1.4 vs 1.1 mg/dl. Lipid profiles were however more significantly abnormal in controls, compared to diabetics with respectively; total cholesterol 220 vs 194 mg/dl, LDL-cholesterol 131 vs 107 mg/dl and triglycerides 206 vs 157 mg/dl. There were no significant differences in HDL-cholesterol; respectively 55 vs 51 mg/dl. In the diabetics, calorific intakes from carbohydrates, especially sugars, were significantly lower than controls i.e. 9% vs 13%. The proportional share of calories derived from dietary fats did not differ between groups, nevertheless a positive correlation was observed between dietary fat content with blood cholesterol concentrations in diabetics. CONCLUSIONS: Disorders of carbohydrate metabolism were confirmed in both overweight and diabetic (type 2) subjects. In addition, both groups demonstrated untoward lipid profiles that correlated with their improper nutrition.

Infant feeding survival and Markov transition probabilities among children under age 6 months in Uganda.

Infant feeding studies are typically presented as single-event models, without considering the dynamic nature of feeding. We analyzed the determinants of infant feeding duration using both single- and multiple-event Cox regression models. The Cox model was compared with parametric survival models, which were used to estimate feeding-state transition probabilities. Data were taken from a community randomized trial promoting exclusive breastfeeding (EBF) in Uganda from 2005 to 2008. Peer counselors visited intervention mothers once antenatally and 4 times after birth. Results showed that children in the control group were more likely to be switched from exclusive breastfeeding (EBF)/predominant breastfeeding (PBF) to mixed feeding (MF)/replacement feeding (RF). Children in intervention clusters (hazard ratio = 0.33, 95% confidence interval: 0.26, 0.42) and rural areas (hazard ratio = 0.79, 95% confidence interval: 0.63, 0.99) had a lower risk of EBF/PBF cessation. Based on the Akaike Information Criterion, parametric models were better fitted than the Cox model. The analytical approach to assessing infant feeding duration used in this study takes into account transitions between feeding categories, allowing for multiple events. This will enhance understanding of infant feeding practices and give policy-makers a better picture of the versatility of infant feeding.

Classification of main meal patterns--a latent class approach.

Relatively little examination of the meals that are prepared in households has been conducted, despite their well-defined properties and widespread community interest in their preparation. The purpose of the present study was to identify the patterns of main meal preparation among Australian adult household meal preparers aged 44 years and younger and 45 years and over, and the relationships between these patterns and likely socio-demographic and psychological predictors. An online cross-sectional survey was conducted by Meat and Livestock Australia among a representative sample of people aged 18­65 years in Australia in 2011. A total of 1076 usable questionnaires were obtained, which included categorical information about the main meal dishes that participants had prepared during the previous 6 months along with demographic information, the presence or absence of children at home, confidence in seasonal food knowledge and personal values. Latent class analysis was applied and four types of usage patterns of thirty-three popular dishes were identified for both age groups, namely, high variety, moderate variety, high protein but low beef and low variety. The meal patterns were associated differentially with the covariates between the age groups. For example, younger women were more likely to prepare a high or moderate variety of meals than younger men, while younger people who had higher levels of education were more likely to prepare high-protein but low-beef meals. Moreover, young respondents with higher BMI were less likely to prepare meals with high protein but low beef content. Among the older age group, married people were more likely to prepare a high or moderate variety of meals than people without partners. Older people who held strong universalist values were more likely to prepare a wide variety of meals with high protein but low beef content. For both age groups, people who had children living at home and those with better seasonal food knowledge were more likely to prepare a high variety of dishes. The identification of classes of meal users would enable health communication to be tailored to improve meal patterns. Moreover, the concept of meals may be useful for health promotion, because people may find it easier to change their consumption of meals rather than individual foods.

Access to excess: how do adolescents deal with unhealthy foods in their environment?

PURPOSE: Easy access to unhealthy foods is believed to contribute to the current overweight epidemic. It remains unclear, however, how access to unhealthy foods is related to self-regulation of food intake. This study tests the hypothesis that using self-regulation strategies buffers the negative influences of easy access to unhealthy foods. METHODS: Cross-sectional survey data from 2764 adolescents aged 10-17 years from four European countries (The Netherlands, UK, Poland and Portugal) about use of self-regulation strategies, access to unhealthy foods and intake of unhealthy foods (sweet and salty snacks and sugar-sweetened beverages) were used. RESULTS: Both access to unhealthy foods and use of self-regulation strategies were independently, but in opposing directions, related to intake of unhealthy foods. Easy access to unhealthy food products was associated with higher consumption, but this effect could be attenuated by use of self-regulation strategies to facilitate healthy eating even when the food environment tempts one to do otherwise. CONCLUSIONS: Health promotion policy and programs should not only address the food environment but could also teach young people better strategies to deal with it.

The Eating Identity Type Inventory (EITI). Development and associations with diet.

People with healthy eating identities report healthier diets and demonstrate greater receptivity to nutrition interventions, but other types of eating identity are likely important. We developed the Eating Identity Type Inventory (EITI) to assess affinity with four eating identity types; healthy, meat, picky, and emotional. This study assessed factorial validity, using confirmatory factor analysis (CFA) and established reliability and convergent validity of the EITI. In a telephone survey, 968 primary household food shoppers completed the EITI and a dietary questionnaire; 101 repeated the EITI approximately 1month later.CFA revealed that an 11-item model provided acceptable fit (χ(2)=206; df=38), CFI=.938, NNFI=.925, RMSEA=.070; SRMR=.059). The EITI demonstrated acceptable internal consistencies with Cronbach alpha's ranging from .61 to .82 and good test-retest reliability for healthy, emotional, and picky types (Pearson's correlations ranging from .78 to .84). Ordinary Least Squares (OLS) used to assess relationships between eating identity type and diet analyses demonstrated significant hypothesized relationships between healthy eating identity and healthier dietary intake and meat and picky eating identities and less healthy dietary intake. The EITI could facilitate behavioral and cognitive research to yield important insights for ways to more effectively design messages, interventions, and policies to promote healthy dietary behaviors.

[Feeding of two amphibian species (Anura: Hylidae) during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina]. / Alimentación de dos especies de anfibios (Anura: Hylidae) en la estaci6n de bajas temperaturas y su relación con la acumulación de energía en Santa Fe, Argentina.

Feeding of two amphibian species (Anura: Hylidae) during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina. In environments with thermal and pluvial seasonality such as those of the Middle Paraná River floodplain (Province of Santa Fe, Argentina), most amphibian species reproduce during the warm season and drastically diminish their activity during winter. Even though, a few species remain active during the cold season, such as Hypsiboas pulchellus that has its reproductive peak during the autumn-winter period (and the consequent energy demand). The objective of this study was to analyze and compare the feeding and development of fat bodies during the low temperature season for H. pulchellus and Dendropsophus nanus. We analyzed entire gastrointestinal tract contents of both species (H. pulchellus = 110 specimens; D. nanus = 114 specimens) and applied an index (IRI%) that combines prey abundance, volume and frequency to describe frogs diets; we used fat bodies weights as indicators of stored energy reserves. We compared diet between species with a niche overlap index (Ojk: 0-1) and used null models to ascribe statistical significance to evaluate overlap; and we analyzed variation in empty guts proportions through months and between species. Also, using ANCOVAs we explored differences in fat bodies, number and volume of prey consumed along months, between species and sexes. The most important preys in H. pulchellus diet during the cold season were Araneae (IRI% = 34.96), Chironomidae (IRI% = 33.08), Tipulidae (IRI% = 11.44) and Gryllidae (IR1% = 7.31); while for D. nanus, Chironomidae (IR1% = 48.14), Tipulidae (IRI% = 18.41), Psychodidae (IRI% = 7.44) and Araneae (IRI% = 7.34). Diet overlap between species was elevated (Ojk=0.78) and higher than expected by chance (mean simulated indices: Ojk = 0.04; p[observed > or = expected]<0.01; p[observed < or = expected] = 1). In H. pulchellus there was a monthly variation in number of prey per gut, while in D. nanus there was a difference in fat bodies development between sexes. Fat bodies development, number of prey per gut and preys volume also varied between species. Despite diet similarity between H. pulchellus and D. nanus, each species showed a different strategy to accumulate energy and support their activity during the cold season. The low rate of gastrointestinal emptiness in H. pulchellus (< 10% in any analyzed month) together with the poor development of their fat bodies, allows us to point out that, to sustain the breeding elevated energy demands, this species continues with a high feeding rate even at the low temperatures of cold season. On the other hand, the rate of gastrointestinal emptiness of D. nanus was higher than that of H. pulchellus (May = 17.24%, July = 22.22% and August = 35.71%), while their fat bodies were well developed. Thus, D. nanus would depend more on their stored reserves to sustain the energy demands of being active during the low temperatures season and hence would reach the reproductive season in spring-summer in good body condition.

Categorization of foods as "snack" and "meal" by college students.

The cognitive representation of a food as being a "snack" or a "meal" influences eating behavior. We found previously that subjects who considered a particular food to be a 'snack' ate significantly more calories when tested later than subjects who considered the same foods as a 'meal'. We conducted two surveys to determine the categorization of foods as "snacks" or "meals". Survey 2 included a larger variety of foods with detailed descriptions and a response option of "never tried". Both surveys found that potato chips, crackers, cookies, and nuts were consistently viewed as snacks, while soups, burritos, pizza, and pancakes were consistently viewed as meals. Useful for future research are foods we found that students varied in considering a snack or meal. Survey 1 found that half the respondents viewed toast, cheese on toast, muffins, and French fries as snacks and the other half as meals. Similarly, in Survey 2 potato salad, toast with jam, English muffin, cinnamon rolls, and nachos were categorized almost equally as snack and meal. These foods can be used in studies looking at the effects of categorizing a food as a meal or snack on other behaviors or categorization, while controlling for the food item.

[Orthorexia--a new diagnosis?]. / Ortoreksja--nowe rozpoznanie?

INTRODUCTION: Orthorexia nervosa (Greek: ortho--correct, right; orexis--appetite, desire) is a term introduced in 1997 by the American doctor Steven Bratman and is defined as a pathological fixation with righteous and healthy eating. Clear classification criteria oforthorexia have not been developed yet and there has been an on-going discussion whether it belongs to the group of eating disorders or the obsessive-compulsive disorders. AIM: The aim of this paper is to summarise briefly the current state of knowledge regarding orthorexia and to point out the difficulties connected with an attempt to classify it in a given disorders group as well as with the attempt to establish the classification criteria. DISCUSSION: Despite the fact that the problem of orthorexia has been signalled in the Polish media, it has neither been discussed nor published in the Polish medical literature yet. Orthorexia starts when a diet becomes an escape from life--everyday activities are dominated by planning, buying and preparing "proper" meals. Each departure from this regime causes anxiety and guilty conscience and leads to even further tightening of the dietary habits. According to Bratmann, orthorexia is connected with an illusory feeling of safety (preventing from diseases), the urge to exercise a full control over one's life (elimination of the unpredictable), "a hidden conformism" (eating philosophy helps in a subconscious way to achieve a culturally accepted model of a beautiful body), a search for spirituality and identity, and a desire for self-deprivation. CONCLUSIONS: The arguments presented in this paper substantiate the expediency of implementing the epidemiological studies which will show the scale of the problem, its prevalence and conditionings. Data obtained in this way should facilitate the verification of classification criteria and will also help to formulate the diagnostic criteria of orthorexia.