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Biomedical subjects

D J Mela

Publications and source records attributed to D J Mela.

At least 19 recordsLinked to original sources
PubMed2006

Metabolically active functional food ingredients for weight control.

The scale of the obesity epidemic creates a pressing consumer need as well as an enormous business opportunity for successful development and marketing of food products with added benefits for weight control. A number of proposed functional food ingredients have been shown to act post-absorptively to influence substrate utilization or thermogenesis. Characteristics and supporting data on conjugated linoleic acid, diglycerides, medium-chain triglycerides, green tea, ephedrine, caffeine, capsaicin and calcium, are reviewed here, giving examples of how these could act to alter energy expenditure or appetite control. Consideration is also given to other factors, in addition to efficacy, which must be satisfied to get such ingredients into foods. We conclude that, for each of the safe, putatively metabolically active agents, there remain gaps in clinical evidence or knowledge of mechanisms, which need to be addressed in order to specify the dietary conditions and food product compositions where these ingredients could be of most benefit for weight control.

Adipose Tissue↗
PubMed2001

Differences in health and taste attitudes and reported behaviour among Finnish, Dutch and British consumers: a cross-national validation of the Health and Taste Attitude Scales (HTAS).

The Health and Taste Attitude Scales (HTAS) developed by Roininen, Lähteenmäki and Tuorila in 1999 measure the importance of health and taste aspects of foods in the food choice process. These multi-item scales consist of sets of statements, ranging from "strongly disagree" to "strongly agree", which further divide into three Health (General health interest, Light product interest and Natural product interest) and three Taste (Craving for sweet foods, Using food as a reward and Pleasure) sub-scales. Finnish (N=467), Dutch (N=477), and British (N=361) respondents completed a questionnaire which contained four components: the HTAS, a separate "paper and pencil task" of choosing a food for a snack; pleasantness, healthiness and frequency of consumption of eight foods; and the Restraint Eating Scale of the Dutch Eating Behaviour Questionnaire (DEBQ). The latter three components were included in order to validate various aspects of the HTAS. The factor structure of HTAS was found to be equal in all three countries. However, there were some minor differences in factor loadings among countries, e.g. the Natural product interest and Pleasure sub-scale items had lower factor loadings in the UK than in Finland and The Netherlands. Finnish respondents had the most positive attitude towards light products. Dutch and British respondents scored higher on all Taste sub-scales than their Finnish counterparts. Respondents' health-related attitudes were good predictors of their "healthy food choices" in the snack task and self-reported consumption. Two of the Taste sub-scales (Craving for sweet foods and Using food as a reward) predicted well respondents' self-reported consumption of, for example, full-fat chocolate bars. All the Health and two of the Taste sub-scales proved to be useful tools for characterizing consumer attitudes within and between countries.

Adolescent↗
PubMed2001

Determinants of food choice: relationships with obesity and weight control.

The decision to eat, and to eat particular foods, varies for different individuals and situations. Individual differences in food likes and desires develop throughout life because of differing food experiences and attitudes. There are many internal and external cues, not just stimulation from foods or hunger, which can trigger the immediate desire to eat or orient eating toward certain foods. Food desires and intake are an outcome of interactions between these cues and more stable individual physiological and psychological characteristics. Overweight and obese individuals show a tendency toward greater liking and selection of energy-dense foods, which may contribute to development and maintenance of these conditions. However, although liking (pleasure from eating) is an important part of food choice, it may make only a modest contribution to overall variation in food choice and eating behaviors. Indeed, difficulties of weight control may reflect problems with cues and motivations to eat, rather than with heightened pleasure derived from eating. Paradoxically, individuals highly concerned with food intake and weight control may be particularly susceptible to thoughts, emotions, and situational cues that can prompt overeating and undermine their attempts to restrain eating. Repeat dieting, high day-to-day fluctuations in intakes, and attempts to enforce highly rigid control over eating all seem to be counterproductive to weight control efforts and may disrupt more appropriate food choice behaviors. Longer-term weight maintenance solutions and programs that offer a degree of structuring of the personal food environment, while retaining flexibility in choices, therefore, may be particularly beneficial in weight management.

Body Weight↗
PubMed2000

Short- and long-term effects of changes in pleasantness on food intake.

This study concerns the effects of pleasantness on ad libitum food intake, liking and appetite over 5 successive days. Pleasantness was manipulated by varying the salt level in bread. Thirty-five students consumed ad libitum sandwiches for lunch, made with bread individually perceived as low, medium or high in pleasantness, in a balanced cross-over design. Pleasantness and desire-to-eat the sandwich were rated at first bite, after the consumption of each sandwich and at the end of the lunch. Fullness was rated just before and at several intervals after lunch. On the first day, the students ate less of the least pleasant bread than of the medium and most pleasant bread. On the fifth day, however, consumption of all breads was similar. For the least pleasant bread, energy intake at lunch, desire-to-eat and fullness, all increased over days, whereas these variables remained constant for the medium and most pleasant bread. Mean pleasantness ratings for all breads remained unaltered across the days. We conclude that, with repeated exposure, the desire-to-eat, fullness and intake of a less preferred food can increase over time. Thus, the relationship between pleasantness and food intake changes over this period.

Adult↗
PubMed2000

UK consumer perceptions of starchy foods.

To gain an understanding of UK consumer attitudes and beliefs regarding starchy foods and their dietary role, a questionnaire based on the theory of planned behaviour was developed and sent out to a UK consumer sample (n 800). The content focused on attitudes and beliefs towards starchy foods, perceived barriers towards increasing their intake (e.g. cost, habit, social influences), perceptions of personal and recommended starchy food intake, intention to increase starchy food intakes in the future and socio-demographic information. Responses (n 414) indicated that consumers have highly divergent attitudes and beliefs regarding starchy foods. These foods are seen as nutritious and good for one's health, but also as high in energy and not helping to control weight, and the overall intention to increase starchy food intake was extremely low. Possible barriers towards increasing starchy food intake were the perceptions that personal starchy food intakes were already high, beliefs that starchy food intakes should be reduced to achieve a healthier diet, and the view that personal starchy food intakes did not need to be changed any further, because (depending on attitude) individual's intakes had already been increased or reduced. The model including attitude and subjective norm had the best fit for predicting reported intention to increase starchy food consumption, with attitude being the strongest contributor. Addition of the factor 'family's liking of starchy foods' significantly improved the model. For reported starch intake, the model including attitude had the best fit, and addition of other factors did not improve the model. These findings indicate that health promotion strategies aimed at increasing complex carbohydrate intakes should take these perceptions into consideration; however, further work is required to examine how these potential barriers can best be addressed in practice.

Attitude to Health↗
PubMed2000

Determination of energy density of freely selected diets: methodological issues and implications.

BACKGROUND: There is increasing evidence that dietary energy density (ED, kJ/g) may be an important dietary characteristic, particularly in respect to control of energy intake; however, there are no agreed methods for deriving the ED of freely selected diets, and ED values may be markedly affected by the inclusion or exclusion of specific dietary items, particularly beverages. OBJECTIVE: To highlight the consequences of using six different methods of ED calculation, and their implications for characterizing differences between weight status groups and identifying associations of ED with macronutrient intakes. DESIGN: ED was calculated using six defined methods: (1) all food and beverages; (2) all food and energy beverages; (3) food, milk and alcohol; (4) food only; (5) all dry matter; (6) protein, carbohydrate and fat only, of varying exclusions of different beverages and water. For illustrative purposes, data from 41 lean (LE, body mass index (BMI) 20-25 kg/m2) and 34 obese (OB, BMI>/=30 kg/m2) adults who kept 4-day weighed dietary intake records are described. RESULTS: ED values (and coefficient of variation, CV) differed substantially by methods of calculation. OB reported significantly greater mean ED compared with LE by one method (all food, milk and alcohol, excluding other non-alcoholic beverages); however, the opposite was found using another method (dry weight). For most calculation methods, ED was negatively associated with percentage energy from carbohydrate for LE, in contrast to OB. All methods found positive correlations for ED and fat (g) among LE, but only one method found such a correlation among OB. Similarly, three methods produced positive correlations between ED and percentage energy fat amongst LE; however, this was only observed amongst OB with one method. CONCLUSIONS: Methods of calculating ED of freely selected diets must be carefully defined, and can markedly influence apparent relationships of ED with other dietary measures and subject characteristics. International Journal of Obesity (2000)24, 49-54

Adult↗
PubMed1999

Food choice and intake: the human factor.

Human perceptions and selection of food are derived from the prevailing and momentary food, agro-economic and cultural environment, cognitive and biological characteristics of individuals, and the real and perceived intrinsic and extrinsic attributes of foods themselves. The range of items typically chosen and consumed within a given population is largely determined by interaction of the external environmental context with guiding sets of implicit and explicit social and psychobiological 'rules'. Within the rather broad limits of biology, individual food choices and intake behaviours relate to and reflect aspects of food availability, existing habitual behaviours, learning mechanisms, and individual beliefs and expectations. Many of the relevant features of these variables are uniquely human, together determining what is 'food', when, how, by and with whom it is chosen and eaten, and in what quantities. They also provide the opportunities for individuals to establish and maintain a relatively stable set of culturally and biologically determined affective responses ('likes') and intake behaviours. Understanding of the potential contribution of these influences under different conditions can serve to explain many of the observed characteristics of human eating, and highlight potential avenues for intervention.

Behavior↗
PubMed1999

Sensory and hedonic associations with macronutrient and energy intakes of lean and obese consumers.

OBJECTIVE: To establish differences between lean and obese subjects in subjective reports of predominant taste and texture attributes of 'foods as eaten', and the relationships of these qualities to hedonic preference and objective measures of dietary intake and composition. DESIGN: Free-living subjects received instruction in a laboratory and kept diaries of foods eaten at home. SUBJECTS: 41 lean (body mass index (BMI) 20-25 kg/m2) and 35 obese (BMI > or = 30 kg/m2), non-dieting healthy adults. MEASUREMENTS: Subjects kept four-day weighed dietary intake records, simultaneously assigning ratings for perceived pleasantness and predominant sensory attributes (taste and texture) of food eaten, and completed the Dutch Eating Behaviour questionnaire (DEBQ). Anthropometric measures included body composition assessed by bioelectrical impedance. RESULTS: By all anthropometric measures (except height) the obese group was significantly larger than the lean group, but no significant differences were found for DEBQ scores. There were no significant group differences between pleasantness scores overall, nor for foods classified by predominant taste. Whilst macronutrient intakes did not differ, the obese group's mean dietary energy density was significantly higher, and they reported significantly greater dietary energy from 'salty' foods. For the obese group, the percentage of 'salty' foods eaten correlated strongly with energy density. A strong positive association was found between 'liking extremely' and 'sweet' foods for the lean group, but no clear associations were found for any particular taste and hedonic rating for the obese group. Whilst both groups used similar texture descriptors, there were not clear or unambiguous differences in their assignment or association with other measures. CONCLUSIONS: The results suggest that obese and lean subjects do not self-select diets with markedly different perceived sensory or hedonic attributes. However obese subjects appear to consume a diet higher in energy density, which is particularly associated with intakes of salty/savoury (rather than sweet) food items.

Adolescent↗
PubMed1998

Sensory and hedonic judgments of common foods by lean consumers and consumers with obesity.

OBJECTIVE: To establish differences between lean subjects and subjects with obesity in subjective reports of predominant taste and texture attributes of common foods, and the relationships of these qualities and foods with overall liking. RESEARCH METHODS AND PROCEDURES: Twenty lean (body mass index: 20 to 25 kg/m2) nondieting healthy adults and 23 (body mass index: > or = 30 kg/m2) nondieting healthy adults with obesity assigned ratings for pleasantness and predominant sensory attributes to 50 common foods in 14 food groups using a questionnaire. They completed the Dutch Eating Behavior Questionnaire. Body composition was assessed by bioelectrical impedance. RESULTS: There were no significant group differences between pleasantness scores overall; however, lean subjects assigned higher scores to fruits and vegetables, to foods self-classified as sweet and as salty/savory, and to foods grouped in the highest and lowest quintiles of percentage food energy from fat. There were no group differences in free-choice texture descriptors applied to foods, but correspondence analysis revealed that subjects with obesity associated coarse, slippery, tough, and fatty textures with "dislike extremely," whereas lean subjects associated grainy, moist, doughy, and fibrous texture with "like extremely." Analyses reduced texture terms to 39 key descriptors for use in subsequent work. Groups did not significantly differ in reported external or restrained eating behaviors, but subjects with obesity scored significantly higher for reported emotional eating. DISCUSSION: Differences in preferences for listed common foods exist between weight status groups according to taste, food group, and texture. Consumers can make textural descriptions of foods that could be used to assess sensory and hedonic qualities of actual food choices.

Adolescent↗
PubMed1998

Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on consumer choice and nutrient intakes.

This study reports results from a randomized controlled intervention trial, focusing on: (1) the identification of successful consumer strategies for increasing fruit and vegetable intakes to the recommended levels of more than five (80 g) portions per day and (2) impact on overall diet and nutrient intakes. Adult men and women (n 170) fulfilling the main recruitment criterion of eating less than five fruit and vegetable portions per day but contemplating increasing intakes were recruited. Complete valid dietary data was provided by 101 intervention (fifty-nine estimated fruit and vegetable intakes, and forty-two simultaneous weighted total dietary and estimated fruit and vegetable intakes) and twenty-four control subjects (weighed total dietary intakes). Intervention advice included the specific association of high fruit and vegetable intake with reduced risk of disease, practicalities, and portion definition with a target intake of greater than five 80 g fruit and vegetable portions per day for 8 weeks. There were significant effects (P < 0.001) on weighed intakes of fruit and vegetables in the intervention group, rising from 324 (SE 25) to 557 (SE 31) g/d and reflected by validated portion measures at 8 weeks intervention. Successful strategies chosen by 'achievers' of the target intake (65% of subjects) were conventional (fruit as a snack, vegetables with main meals etc.) and favoured fruit. There were significant increases in percentage energy from carbohydrate (from sugars not starch), vitamin C, carotenes and NSP and there was a significant decrease in percentage energy from fat for subjects who had high fat intakes (> 35% energy) at baseline. Follow-up self-reported measures at 6 and 12 months indicated mean intakes of 4.5 and 4.6 defined portions/d respectively, suggesting some sustainable effect. In conclusion, the intervention led to significant increases in fruit and vegetable intakes largely via conventional eating habits, with some desirable effects on macro- and micronutrient intakes.

Adolescent↗
PubMed1998

Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on attitudes towards dietary change.

To assess the response of low consumers of fruit and vegetables to a nutrition education intervention programme, data were collected from 104 adults on attitudinal variables related to 'eating more fruit, vegetables and vegetable dishes'. Questionnaires (based on the theory of planned behaviour) assessing perceived barriers to increasing fruit and vegetable consumption were administered before an action-orientated intervention programme and at the end of the intervention period (8 weeks). Questionnaire scores for belief-evaluations in the intervention groups pre- and post-study indicated that support of family and friends, food costs, time constraints and shopping practicalities (in order to increase intake of fruit, vegetable and vegetable dishes) were barriers to greater consumption of these foodstuffs. Perceived situational barriers to increasing intakes of fruits and vegetables were: limited availability of vegetables, salads and fruit at work canteens, take-aways, friends' houses and at work generally. Following the intervention the number of visits to the shops was perceived as a greater barrier for increasing intakes of fruit and vegetables. Perceived practical opportunities for increasing intakes high-lighted drinking fruit juice, taking fruit as a dessert, having fruit as a between-meal snack and eating two portions of vegetables with a meal. About two-thirds of intervention subjects achieved the recommended fruit and vegetable target, but it is concluded that practical issues and situational barriers need to be addressed for the success of future public health campaigns.

Adolescent↗
PubMed1998

UK consumer attitudes, beliefs and barriers to increasing fruit and vegetable consumption.

OBJECTIVES: To assess attitudes, predictors of intention, and identify perceived barriers to increasing fruit and vegetable (F&V) intakes. DESIGN: UK nationwide postal survey utilizing the theory of planned behaviour. SUBJECTS: Stratified (by social class and region) random sample of 2020 UK adults providing a modest response rate of 37% (n = 741). RESULTS: Belief measures (e.g. health, cost, taste, etc.) were strongly associated with overall attitudes which were reported as being largely favourable towards fruit, vegetables and, to a lesser extent, vegetable dishes, and were strongly associated with reported intention to increase consumption. Subjects reported they could increase their consumption, but this was only weakly associated with intention to do so. Approximately 50% of respondents reported an intention to increase intakes. Social pressure was strongly associated with reported intention to increase; however, scores indicated low perceived social pressure to change. Evidence of unrealistic optimism concerning perceived intakes and the perceived high cost of fruit may also act as barriers. CONCLUSIONS: Results from this study suggest a lack of perceived social pressure to increase F&V intakes and suggests that public health efforts require stronger and broader health messages that incorporate consumer awareness of low present consumption.

Adolescent↗
PubMed1997

Perceptions of starchy food dishes: application of the Repertory Grid Method.

The Repertory Grid Method (RGM) was applied to obtain an understanding of the characteristics used by U.K. consumers in discriminating amongst different common starchy food dishes, including potatoes, rice and pasta. Twenty-nine subjects generated a large number of constructs, relating to perceived nutrition, health physiological effect, sensory, and use attributes of these products. Coupling of RGM with Generalized Procrustes Analysis produced detailed qualitative and quantitative information describing common and individual characteristics of particular dishes. The results indicate that starchy foods are in general seen as "filling", but specific products are clearly discriminated along two dimensions, predominantly relating to nutritional value ("healthy", "fatty", "fattening") and sensory/functional characteristics ("versatile", "bland", "boring", "a meal in itself"). Along with further analysis of the sensory descriptors, these results indicate the utility and efficiency of RGM for clarifying consumer views of broad food categories, while identifying the potential acceptability of particular starchy foods in fulfilling current dietary goals.

Adult↗
PubMed1997

Measuring fruit and vegetable intake: is five-a-day enough?

OBJECTIVE: Validation of a self-monitoring "portions' measurement of fruit and vegetable (F&V) consumption against a standard of weighed intakes. DESIGN: Component of a randomized controlled trial. SETTING: Subjects attended research centres in Reading and Glasgow for instruction and monitoring but undertook free-living dietary changes at home. SUBJECTS: A study sample of 42 adult men and women fulfilling the main recruitment criterion of eating less than five F&V portions/day but contemplating increasing intakes and providing weighted baseline reported energy intakes exceeding (estimated basal metabolic rate x 1.1). INTERVENTIONS: Subjects attended an intensive group advice session which included the specific relationship of high F&V intake with reduced risk of disease; practicalities; portion definition and measurement recording. The target was to exceed five F&V portions/day for 8 weeks. MAIN OUTCOME MEASURES: Self-recorded simultaneous weighed inventories and F&V portion measures. RESULTS: Data from subjects who were not evident under-recorders showed correlations between portion and weighed intakes of r = 0.73, (P < 0.000), although the portions measure tended to under-estimate intakes. Using 80 g/portion the "5-a-day' concept tends to create false negatives (namely consumption could be greater than 400 g whilst recording fewer than five discrete portions) but rarely false positives (namely recorded consumption of less than 400 g did not give measures of more than five discrete portions). CONCLUSIONS: The data suggest that the five portions F&V/day health message, if used in conjunction with defined discrete portions, would encourage desirable consumption exceeding 400 g.

Adolescent↗
PubMed1997

Extended use of foods modified in fat and sugar content: nutritional implications in a free-living female population.

The nutritional implications of the consumption of reduced-fat and reduced-sugar foods were assessed in nonobese, free-living female consumers in a 10-wk intervention trial. Subjects in control (C; n = 13), reduced-fat (RF; n = 17), and reduced-sugar (RS; n = 19) groups, all initially nonusers of reduced-fat and reduced-sugar products, kept 4-d food-intake records to establish energy and macronutrient intakes at baseline and at 2,4,7, and 10 wk. Groups RF and RS were instructed to use reduced-fat and reduced-sugar foods, respectively, ad libitum in place of habitually consumed foods with traditional composition, whereas group C was to maintain their usual diet. All foods were purchased by subjects in normal retail outlets and consumed at home. Analyses revealed no main or interactive effect of group on reported energy intake. RF subjects reduced their reported fat intake during the study (P = 0.017) compared with RS and C subjects, and RS subjects reduced their reported sucrose intake compared with RF and C subjects (P = 0.049). Group differences in total sugar intake were not significantly different. All groups reported a small but significant increase in reported protein intake during the study, whereas there were no significant effects on percentage energy from total carbohydrate. Body weights did not change significantly in any group over the study period. These results indicate that, as a single dietary strategy, casual use of macronutrient-substituted foods by consumers under normal eating conditions can significantly influence the macronutrient composition of the diet, but has little net effect on total energy intake or body weight status.

Adolescent↗