Macronutrient Content Of Foods Research Articles

Co-administration of bromocriptine and corticosterone produces short- and long-lasting reduction in intake of high-fat food in male rats.

Dopaminergic and glucocorticoid activity has been associated with reduced food consumption; however, their possible synergic action has not yet been studied. With the aim of examining the effect of the co-administration of the dopamine receptor D2 agonist bromocriptine and corticosterone on palatable food intake, male Wistar rats were administered either bromocriptine (1 mg/kg), corticosterone (2 mg/kg), bromocriptine + corticosterone (1 mg + 2 mg/kg) or a vehicle, with a fifth group used as a control. In all cases, substances were administered 30 min before exposure to standard food or palatable food, the latter high in carbohydrates [high carbohydrate food (HCF), 75%] or high-fat food (HFF, 67%). Food consumption and body weight were recorded daily. Results showed higher consumption of standard food but lower consumption of HCF and HFF in the groups that received bromocriptine, alone or in combination. In general, lower total kcal intake was observed in the bromocriptine and bromocriptine + corticosterone groups during the period of pharmacological treatment and following re-exposure to palatable food. The low HFF intake in the bromocriptine + corticosterone group persisted 10 days after the pharmacological treatment was interrupted. This effect suggests plastic changes in either the mechanisms involved in the incentive value of palatable food - particularly foods with high-fat content - or those that regulate lipid metabolism. Our findings suggest that homeostatic and reward mechanisms could be influenced by the co-participation of the dopaminergic and hypothalamic-pituitary-adrenal systems, and the macronutrient content of food.

Validation and measurement invariance of the Muscularity-Oriented Eating Test among Brazilian men and women.

The Muscularity-Oriented Eating Test (MOET) is a 15-item unidimensional scale, designed to assess eating practices that occur in the pursuit of a muscular body. The aim of the present study was to describe the translation and cultural adaptation of the MOET to Brazilian Portuguese, to explore its factor structure and measurement invariance, and to evaluate its internal consistency, three-week test-retest reliability, and convergent validity in a community sample of Brazilian men and women. After the back-translation procedure, the Brazilian MOET was administered online to a sample of 1246 adults (634 men and 612 women), along with measures of drive for muscularity, muscle dysmorphia symptoms, muscular/athletic-ideal internalization, disordered eating behaviors, and exercise dependence. Findings from an exploratory factor analysis and a confirmatory factor analysis revealed a one-factor structure and adequate internal consistency for men (ω=0.86; α=0.86) and women (ω=.84; α=.83). Measurement invariance across gender was supported. In addition, the scale demonstrated good three week test-retest reliability for both men (ICC=.96; p < .001) and women (ICC=.92; p < .001), and the subscales revealed moderate to large associations with drive for muscularity, muscle dysmorphia symptoms, muscular/athletic-ideal internalization, disordered eating, and exercise dependence. This study supports the validity and reliability of the MOET in a community sample of Brazilian men and women and represents an advance in measures of muscularity-oriented disordered eating in Brazilian adults, allowing for future cross-cultural studies in this field. The Muscularity-Oriented Eating Test (MOET) is a measure of muscularity-oriented disordered eating, which assess strict adherence to diet rules, including the food's macronutrient content, regulation of protein intake, and eating less or more to influence muscle gain. This study evaluated the validity and reliability of the MOET in a community sample of Brazilian men and women. Our findings represent an advance in measures of muscularity-oriented disordered eating in Brazilian adults.

A Two-Level Food Classification System For People With Diabetes Mellitus Using Convolutional Neural Networks.

Accurate estimation of food's macronutrient content for people with Diabetes Mellitus (DM) is of great importance, as it determines postprandial insulin dosage. This paper introduces a classification system for food images that is adjusted to the nutritional needs of people with DM. A two-level image classification scheme, exploiting Convolutional Neural Networks (CNNs), is proposed, in order to classify an image in one of eight broad food categories with similar macronutrient content and then assign it to a specific food within that category. To this end, a visual dataset, namely NTUA-Food 2017, has been designed, consisting of 3248 images organized in eight broad food categories of totally 82 different foods. Moreover, a novel evaluation metric is proposed, which penalizes classification errors proportionally to the discrepancy in postprandial blood sugar levels between the actual and predicted class. The proposed system achieves 84.18% and 85.94% classification accuracy at the first and second level of classification, respectively, on the NTUA-Food 2017 dataset. The algorithm developed for the first level of classification on the NTUA-Food 2017 dataset improves classification accuracy on the benchmark Food Image Dataset (FID) to 97.08% outperforming previous approaches. The algorithm's mean error in terms of carbohydrate content estimation on the NTUA-Food 2017 dataset is less than 2 g per food serving.

Gross vs. net income: How plant toughness affects performance of an insect herbivore

Leaf biomechanical properties are thought to impose a significant obstacle to herbivores and as such influence patterns of herbivory more than leaf chemistry. However, evidence for the role of structural traits in influencing herbivore food choice and performance has come from correlative studies, whereas the underlying mechanisms have been given little attention. By manipulating the biomechanical properties of a host grass species through a combination of lyophilization and milling, and providing water separately, we were able to compare behavioral, physiological, and developmental responses of the Australian plague locust, Chortoicetes terminifera, to the biomechanical properties of plant food (exemplified by toughness) independently of the food's macronutrient content and the insect's demand for water. Increasing leaf toughness was associated with reduced rates of locust growth and prolonged development, with potential ecological consequences. Poorer performance on the tougher foods was primarily a consequence of a reduced rate of nutrient supply, which occurred as a result of (1) smaller meals being eaten more slowly, (2) slowed gut passage rates, which limited how quickly the next meal could be taken, and (3) reduced efficiency of assimilation of nutrients from food in the gut. In addition, there were deleterious changes in the ratio of protein to carbohydrate assimilated from the gut. Prolonged development time was associated with increased total nutrient demands throughout the extended developmental period. Because these demands could not be met by increased consumption, there was a decreased efficiency of conversion of assimilated nutrients to growth. By disentangling the effects of biomechanical properties from macronutrient and water content we have shown that leaf biomechanical traits can influence chewing herbivores independently of leaf chemical traits.

Characteristics of Self-Selected Portion Size in Young Adults

Objective Individuals’ perceptions of portion size have not been examined with respect to body mass index (BMI; calculated as kg/m 2), food form, food macronutrient, or food-energy density. The primary objective of this investigation was to evaluate the characteristics surrounding college students’ perception of typical portions of real food items. Design This study was designed as a quasi-experiment with independent repeated measures of food form (amorphous, solid, liquid), food macronutrient content (low carbohydrate, high carbohydrate, low fat, high fat), and food-energy density (low, high), as well as one independent subject variable of sex (male, female). The main dependent measure was self-selected portion size representing what each participant felt was their typical portion of 15 food/beverage items. In addition, BMI was treated as a continuous predictor variable in regressions for portion-size estimation. Results Participants (n=51) chose substantially larger portion sizes as compared to reference portion sizes in 10 of the 15 food/beverage items. When accounting for intervening variables, BMI positively predicted self-selected portion size for six of 15 food/beverage items ( R 2=0.29 to 0.38). In addition, participants chose significantly larger portion sizes for high-carbohydrate foods when compared to high-fat foods (191.65 vs 145.40 g; P=0.004). Conclusions A strong relationship between BMI and large portion sizes for high-energy-density foods, snacks, and high-carbohydrate foods was found. In addition, participants selected much smaller portion sizes for high-fat foods items relative to high-carbohydrate foods.

Effects of the Nitric Oxide Synthase Inhibitor NG-Nitro-L-Arginine Methyl Ester (L-NAME) on Antropyloroduodenal Motility and Appetite in Response to Intraduodenal Lipid Infusion in Humans

Background: Studies in animals indicate that endogenous nitric oxide (NO) is an important inhibitory neurotransmitter in the gastrointestinal tract and that it modulates food intake. We evaluate the role of NO mechanisms in mediating the effects of small intestinal nutrients on antropyloroduodenal motility and appetite in humans. Methods: On 2 separate days, 8 healthy adult men received intravenous L-NAME 180 µg/kg/h or 0.9% saline (0-150 min); between 30 min and 120 min, an intraduodenal lipid infusion (2 kcal/min) was administered, and at 120 min subjects were offered a buffet meal (120-150 min). Antropyloroduodenal pressures were measured with a sleeve/sidehole manometric assembly. During the infusions, perceptions of hunger and fullness were assessed with visual analog questionnaires and amount and macronutrient content of food consumed at the buffet meal were quantified. Blood pressure and heart rate were monitored at regular intervals. Results: Intraduodenal lipid infusion was associated with increases in fullness (P < 0.05) and in frequency of isolated pyloric pressure waves (P < 0.05) and basal pyloric pressure (P < 0.05); and decreases in hunger (P < 0.05) and in frequency of antral (P < 0.05) and duodenal (P < 0.05) pressure waves. L-NAME increased diastolic blood pressure (P = 0.08) and decreased heart rate (P < 0.05), but had no effect on antropyloroduodenal pressures or food intake. Conclusions: Intravenous administration of the systemic NO synthase inhibitor, L-NAME, in a dose that affects cardiovascular function in healthy humans does not modify the antropyloroduodenal motor and appetite responses to intraduodenal lipid infusion.

Food intake regulation in children. Fat and sugar substitutes and intake.

A series of experiments exploring children's responsiveness to manipulations of energy density and macronutrient content of foods have been reviewed to assess the nutritional impact of macronutrient substitutes on children's intake. In these experiments, the focus is on the extent to which the energy content of foods was a salient factor influencing children's food intake, and macronutrient substitutes were used as tools to investigate this issue. Therefore, although several different macronutrient substitutes have been used in this research, we do not have a parametric set of experiments systematically assessing the impact of a variety of macronutrient substitutes. Given this, what can we conclude from the existing data? When the energy density and macronutrient content of foods is altered through the use of macronutrient substitutes that reduce the energy content of foods, children tend to adjust for the missing energy, although this adjustment may be partial and incomplete. This suggests the possibility that when macronutrient substitutes are used to reduce the energy content of foods, children's energy intake may be reduced. This adjustment, however, will most likely be less than a "calorie for calorie" reduction. In addition, even among young children, there are individual differences in the extent to which children adjust their intake in response to macronutrient and energy manipulations. The data are more extensive and particularly clear for cases in which CHO manipulations are used to alter energy density, but there is evidence for adjustments in energy intake in response to alterations of the fat content of the diet. The compensation for energy is not macronutrient specific; that is, when the fat content of food is reduced to reduce energy density of foods, children do not selectively consume fat in subsequent meals. This means that manipulations of macronutrient content of foods that reduce foods' energy content may not result in alterations of energy intake, but because these adjustments in energy intake are not macronutrient specific, changes in the overall macronutrient composition of children's diets can be obtained. There does not appear to be anything unique or special about the effects of macronutrient substitutes on children's intake; their effects are similar to those produced by other manipulations of macronutrient and energy content accomplished without macronutrient substitutes (e.g., augmenting foods with fat or carbohydrate to produce macronutrient differences). The research also indicates that under conditions that minimize adult attempts to control how much and what children eat, children can adjust their food and energy intake in response to the alterations of macronutrient and energy content of foods. Whether or not young children adjust food intake to compensate for energy-density changes depends upon their opportunity to control their own food intake as opposed to having their intake controlled by others. Young children's ability to adjust intake in response to alterations in the energy density of foods can be readily disrupted by the imposition of controlling child-feeding practices that attempt to regulate what and how much children eat. We believe that early experiences, including child-feeding practices imposed by parents, are major factors contributing to the etiology of individual differences and gender differences in the behavioral controls of food intake that can occur in response to the energy content of foods. The extent to which children respond to energy density of the diet has major implications for the effects of fat and sugar substitutes on children's intake. If children who are responsive to energy density consume substantial amounts of foods containing macronutrient substitutes, they should show some adjustments in intake to compensate for reduced energy, so that the impact of macronutrient substitutes on energy intake may be relatively small. However, changes in macronutrient com

Human dietary responses to covert manipulations of energy, fat, and carbohydrate in a midday meal

Dietary responses to dilution or supplementation of the energy value and macronutrient content of foods are poorly characterized in humans. After a 1-wk baseline, 16 free-living, normal-weight adults were provided midday meals systematically varying in energy, fat, and carbohydrate contents for 5-d periods. Their compensatory free-feeding intake was monitored through diet records. In response to energy dilution by carbohydrate or fat, mean daily energy intake was 88% and 97% of baseline, respectively. Responses to the energy surfeit led to intakes 104% and 116% of baseline, respectively. However, the absolute magnitude of the carbohydrate supplement challenge was small. Adjustments of macronutrient-specific intake during the high-carbohydrate, low-carbohydrate, high-fat, and low-fat meal periods were 134%, 91%, 165%, and 95% of baseline, respectively. Although these group findings indicate that defense against covert dilution of the energy, fat, or carbohydrate contents of a meal is stronger than that to supplementation, individual responses were highly variable.