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Biomedical subjects

J M De Castro

Publications and source records attributed to J M De Castro.

18 recordsLinked to original sources
PubMed1999

Heritability of hunger relationships with food intake in free-living humans.

The heritability of the before and after meal self-ratings of hunger and thirst and their relationship to food intake was investigated with 110 identical and 102 fraternal same-sex and 53 fraternal mixed-gender adult twin pairs who were paid to maintain 7-day food intake diaries. From the diary reports, the total and meal intakes of food energy and the amounts of the macronutrients ingested were estimated. Subjects rated their subjective levels of hunger on a seven-point scale both before and after eating. Linear structural modeling was applied to investigate the nature and degree of genetic and environmental influences and revealed significant genetic influences on the self-rated levels of hunger both before and after the meals and the change in hunger over the meal. In addition, the relationship between hunger and intake was influenced by the genes. Significant heritabilities were found for the correlations, and the slopes of the regression lines relating before-meal hunger to meal size and also the change in hunger over the meal to intake. This indicates that hunger's effect on intake and, in turn, intake's effects on hunger are to some extent heritable. This suggests that the level of subjective experience and the individuals responses to them are influenced by the genes and become part of the total package of genetically determined physiological, socio/cultural, and psychological processes that regulate energy balance.

Adult↗
PubMed1997

Socio-cultural determinants of meal size and frequency.

Total energy intake and the frequency and size of meals are profoundly influenced by the socio-cultural context in which it occurs. Simply eating with one other person increases the average amount ingested in meals by 44% and with more people present the average meal size grows even larger. The impact of social facilitation of energy intake on the individual appears to result from genetic effects both on the individuals' sensitivity to the presence of other people and also on the number of other people an individual tends to eat with. Culture markedly affects the choice of foods in the diet and the pattern of meals over the day. However, many of the social, psychological and physical variables that influence intake are similar across cultures.

Cross-Cultural Comparison↗
PubMed1996

How can eating behavior be regulated in the complex environments of free-living humans?

The eating behavior of humans in their natural environments is complexly affected by a myriad of nutritional, physiological, psychological, sociological and cultural factors. We have employed the diet diary technique to document the influence of: the subjective states of hunger, the amount of food or fluid remaining in the stomach at the onset of ingestion, and its composition, the time of day, day of the week, phase of the moon, month of the year, the location, the number of people present, the relationship of eating companions to the subject, dietary restraint, and eating disorders. Recently we have demonstrated, with twins, significant heritabilities for the amounts of foods and fluids ingested, independent of body size. By viewing behavior in free-living conditions the relative importance of these factors in the determination of the amounts and timing of intake can be discerned and measured. The analysis indicates that immediate environmental, psychological, social, and cultural stimuli exert powerful but short-lived effects on intake. Physiological stimuli, on the other hand, appear to influence intake subtly but persistently. Their influences are difficult to document on the short-term, but clear over long periods of time. Short-term intake for the most part would appear to be unregulated and allow to vary spontaneously within a relatively wide range. Physiological variables appear to feed back after a delay of at least a day and usually longer to alter the overall level of intake of bias. The persistent bias continues to shift intake, producing a cumulative net alteration of intake, while the effects of random short-term influences average over tome, and result in no effect on intake.

Eating↗
PubMed1994

Methodology, correlational analysis, and interpretation of diet diary records of the food and fluid intake of free-living humans.

The diet diary technique can produce reliable and valid records of the food and fluid intake of free-living humans. Procedures to maximize accuracy by motivating subjects, verifying records and minimizing bias are described. Underestimation and random error may tend to obscure relationships but does not artifactually produce them. Meal pattern analysis of the diary records relates the meal size, composition and intermeal interval to preceding conditions with univariate and multivariate regression techniques. Although causation cannot be conclusively demonstrated, the analyses can test for potential causal influences. It is concluded that the diet diary technique is the method of choice for investigations of the ingestive behaviours of free-living humans.

Data Interpretation, Statistical↗
PubMed1993

Age-related changes in spontaneous food intake and hunger in humans.

Elderly people eat less than younger individuals. The nature of the changes in the meal pattern that occur with age were investigated by having 307 healthy adults, ages 20 to 80, maintain 7-day diaries of everything they ingested, the timing and conditions present, and subjective hunger, anxiety, depression, and activity. The lower intakes that occur with age were a consequence of the ingestion of smaller meals, eaten relatively slowly. The elderly were as responsive as younger subjects to a number of influences on intake, the time of day, the number of other people present, the subjective state of hunger, and the premeal contents of the stomach. These results suggest that the lower intakes in the elderly are a normal response to lower caloric expenditures. The state of hunger in the elderly affected intake equivalently to the young but intake did not affect hunger to the same extent as in younger subjects. This suggests that the internal state becomes less able to influence the subjective state as aging progresses and as a result the intake of the elderly may become primarily influenced by external factors.

Adult↗
PubMed1993

The effects of the spontaneous ingestion of particular foods or beverages on the meal pattern and overall nutrient intake of humans.

The influence of the ingestion of particular beverages and foods on the overall nutrient intakes and meal patterns of humans was investigated by paying 323 adults to maintain 7-day diaries of everything they ingested, time of ingestion, and subjective and social conditions. Ingestion of noncaloric beverages, diet sodas, and coffee or tea, were associated with low overall intakes but were not found to influence the amount eaten over the course of the day or in individual meals. Fifteen different caloric containing drink or food types were found, in general, to add to the total calories ingested in meals or over the day without displacing calories ingested in other forms. The results indicate that individual foods or beverages are ingested independent of other constituents and that intake within meals or over the entire day is elastic and readily influenced by nonregulatory factors.

Adolescent↗
PubMed1990

Social facilitation of duration and size but not rate of the spontaneous meal intake of humans.

The amount eaten by humans in spontaneously ingested meals is positively correlated with the number of other people present. In order to investigate whether this social facilitation of eating was due to an increase in arousal, emotionality, hunger, or social interactions, analyses were performed on the data obtained from 82 adult humans. They were paid to maintain 7-day diaries of everything they ingested, when and where they ingested it, the number of other people present, and their subjective states of hunger, elation, and anxiety. The presence of other people was found to be associated with the duration of meals and not the rate of intake, whereas self-rated hunger was found to be associated with the rate of intake and not the duration of meals. Self-rated anxiety was not found to be associated with the number of people present, whereas self-rated elation was positively correlated with the presence of others. Multiple regression analyses suggested that the presence of other people facilitates intake and increases elation independently. It also suggested that social facilitation operates by independently increasing the size and the duration of meals and that it operates independently of the subjective state of the individual. These results contradict the predictions of increased arousal, increased hunger, and increased emotionality models but support attentional, disinhibitory, and time extension models of social facilitation.

Adolescent↗
PubMed1990

Running addiction: measurement and associated psychological characteristics.

Runners frequently become addicted to running and continue to run even when it is detrimental to their health. In the present study a paper and pencil test to measure running addiction, the running addiction scale (RAS) was constructed and evaluated and used to investigate the psychological correlates of running addiction. The RAS, symptom check list, locus of control scale, commitment to running scale (CR), and a questionnaire about the individual's running habits and degree of addiction were administered to 32 male and 15 female runners. The results suggest that the RAS is reliable and valid, correlating with self-rated addiction. The CR score was correlated with self-rated addiction for males but not for females suggesting that the RAS and CR measure different characteristics and that for female runners commitment to running can occur without addiction. Large gender differences were found in the correlations between the RAS, CR, run frequency, and run duration with the personality, mood, and locus of control scores. Running addiction was found to be associated with high frequency of running and with positive personality characteristics but not with mood enhancement, while the duration of running was found to be associated with mood enhancement. These results suggest that the benefits of running to mood may be obtained without addiction.

Adult↗
PubMed1975

Meal pattern correlations: facts and artifacts.

The feeding behavior of 37 albino rats was used to demonstrate that significant postprandial correlations could be obtained from unordered raw data when actual intake was used as the measure of meal size. When meal duration was used instead, substantially lower correlations were obtained. It was further demonstrated that caution must be used when correlating ratio measures of feeding behavior. If the ratios are not independent then significant correlations can be obtained due to statistical bias alone. Implications and suggestions for the analysis of meal patterns were discussed.

Animals↗
PubMedDate not supplied

Food intake by brain-injured humans who are in the chronic phase of recovery.

This study examined whether survivors of traumatic brain injury differ from normal, non-injured controls in the regulation of food intake in their natural environment. Caregivers of 20 brain-injured subjects and 20 controls recorded in diaries: caloric intake, time of meals, subjective hunger ratings, and the number of persons present during meals for 7 consecutive days. Brain-injured subjects ate larger meals and more total (overall) calories per day compared with controls. In addition, the presence of other people during a meal, or social factor, was a significant predictor of meal size for the control subjects, but not for the brain-injured subjects. Brain-injured subjects also differed from control subjects in their response to pre-meal stomach content.

Activities of Daily Living↗