Dietary restraint in relation to nutrient intake, physical activity and iron status in adolescent females

Relationships between Iron Status and Selected Physical Fitness Components of South African Adolescents: The PAHL-Study

Poor iron status is detrimental to physical and cognitive performance in adolescents. Due to the limited studies investigating the association between iron status and physical fitness components in adolescents from low- and middle-income countries, we aimed to determine the association of iron status with selected physical fitness components in South African adolescents. A cross-sectional study design, including 178 adolescents (102 girls and 76 boys) from the Physical Activity and Health Longitudinal Study (PAHLS), was followed. Height and weight were measured to calculate the body mass index (BMI). Subsequently, WHO BMI-for-age-specific categorised body fatness. Cardiorespiratory fitness was determined with a 20-m shuttle run test (V˙O2max), and lower-body explosive power by the standing broad jump (SBJ). Fasting haemoglobin (Hb) and ferritin were analysed from blood samples. Correlation analyses determine the association between iron status, explosive power and cardiorespiratory fitness. Of the 178 participants, 18.5% (n = 33) had low Hb, and 14% (n = 25) iron deficiency without anaemia. Significant positive correlations were found between the selected physical fitness components, ferritin, and Hb. In boys, a positive association was found between Hb and SBJ (r = 0.30, p = 0.006), whilst in girls, positive associations were found between ferritin (r = 0.25, p = 0.04) and SBJ, and Hb with both SBJ (r = 0.21, p = 0.03) and V˙O2max (r = 0.32, p = 0.001). Hb concentration remained associated with V˙O2max and SBJ in girls after adjustment for age, whilst in boys, Hb concentration was associated with SBJ. Higher iron status in South African adolescents is associated with higher lower-limb explosive power and cardiorespiratory fitness. We suggest monitoring of haematological parameters, and interventions to improve the iron status of South African adolescents.

Restrained eating behaviour, anorexia nervosa and food consumption between children and adolescents: a scoping review

Anorexia nervosa (AN) and restrained eating behaviour (REB) are characterised by reduced food intake to achieve body weight loss. This scope review aimed to describe the existing evidence on the association between AN, restrictive eating behaviour and food consumption. Studies with children and adolescents of both sexes of all races and ethnicities were included. Experimental and observational studies, systematic reviews, meta-analysis, case reports or series, conference abstracts, dissertations and theses were also included. The search was conducted in ten electronic databases and grey literature without language restriction on 14 November 2020. Twenty-four studies met the inclusion criteria. Most studies included girls and identified lower intake of energy content, fat and certain micronutrients. There was also a higher intake of caffeine, fibre, vegetables, legumes and fruits and a lower intake of low-quality snack, fast food, sweets and foods with high carbohydrate and fat contents. The need to improve the quality of the diet among study participants was also identified. Thus, it is recommended that the evaluation of food consumption be careful to develop effective prevention strategies for the development of AN/REB and minimise nutritional deficiencies in these individuals.

Obesogenic eating behaviour and dietary intake in German children and adolescents: results from the GINIplus and LISA birth cohort studies

BACKGROUND/OBJECTIVES

The transition to adolescence is characterised by considerable behavioural changes, including diet. This study describes the level of obesogenic eating behaviours in 10- and 15-year-olds, and their association with dietary intake.

SUBJECTS/METHODS

Participants of the 10- and 15-year follow-ups of the German GINIplus and LISA birth cohort studies were included (N₁₀ = 2257; N₁₅ = 1880). Eating behaviours and dietary intake were assessed via self-report questionnaires. Sex-stratified, cross-sectional associations of "external eating", "emotional eating" and "dietary restraint" (the latter at age 15 years only) with dietary intake (17 food groups-categorised into tertiles, macronutrients, and total energy) were assessed using multinomial logistic or multiple linear regression as required, adjusting for covariates and correcting for multiple testing.

RESULTS

Reported levels of eating behaviours were low in both age-groups. External eating was higher in 10-year-old males than females, while all eating behaviours were most pronounced in 15-year-old females. At 10 years, emotional eating was associated with medium vegetable intake in females (Relative Risk Ratio (RRR) = 1.84, p = 0.0017). At 15 years, external eating was associated with total energy (kJ) in females (β = 718, p = 0.0002) and high butter intake in males (RRR = 1.96, p = 0.0019). Dietary restraint in females was inversely associated with total energy (β = -967, p < 0.0001) and omega-3 fatty acids (Means Ratio (MR) = 0.94, p = 0.0017), and positively associated with high fruit (RRR = 2.20, p = 0.0003) and whole grains (RRR = 1.94, p = 0.0013).

CONCLUSION

Obesogenic eating behaviour scores are low among children and adolescents of a predominantly high socioeconomic status population and present only few associations with specific aspects of diet, mainly among adolescent females.

The relative contributions of body image evaluation and investment in the prediction of dietary restraint in men

This study examined the importance of body image evaluation and investment to predict dietary restraint in men ( N = 272). Measures of physical activity, evaluation, investment and dietary restraint were completed. A hierarchical regression was conducted to predict dietary restraint from physical activity and body mass index (entered on the first step), body image evaluation (entered on the second step) and investment (entered on the final step). The overall regression was significant, F(4, 271) = 15.12, p < .001, R2adj = .17). Body mass index, physical activity and body image investment were significant positive predictors of dietary restraint. The present findings emphasize measuring body image investment.

Eating attitudes and behaviours in elite Canadian athletes with a spinal cord injury

Athletes with a spinal cord injury (SCI) appear to have relatively modest energy requirements despite demanding training regimes. Virtually nothing is known about the factors which influence the energy intake of those with a SCI including food related attitudes and behaviours. Using a cross-sectional observational design, three aspects of eating attitudes were measured using the Three-Factor Eating Questionnaire (TFEQ) along with six days of self-reported dietary intake and anthropometrics. Between March 2007 and May 2009, a total of 32 Canadian athletes with a SCI (n=24 men, n=8 women) completed the study. The TFEQ scales showed a cognitive dietary restraint score of 10.8±4.7, disinhibition score of 2.8±1.8 and hunger score of 3.1±2.2. When the group was split into high and low restraint groups using a median of 11.5, no differences were detected in any of the absolute parameters of reported dietary intake although the higher restraint group had protein intakes account for a greater proportion of total energy. Those with higher restraint scores also had a relatively higher disinhibition score. While the cognitive dietary restraint scores for the women were similar to other able-bodied populations, the scores for men were higher than population norms from other studies. The scores for disinhibition and hunger were lower than reported ranges from able-bodied subjects. These athletes may be actively monitoring or limiting dietary intake to avoid the high prevalence of obesity associated with a SCI or perhaps to maintain an ideal body composition for their sport performance.

Differences in diet composition of Brazilian adolescent girls with positive or negative score in the Eating Attitudes Test

Dieting, a behavioral phenomenon which is becoming more frequent among adolescents, is certainly involved in the pathogenesis of eating disorders, especially anorexia nervosa (AN), and may result in an unbalanced nutrition. Our study aimed at identifying girls with symptoms of AN and describing their diets. We assessed girls with symptoms by using the Eating Attitudes Test and considered girls with a score > or = 20 as having symptoms of AN. To evaluate their diets, a "modified" 24-hour recall was applied on three alternate days. Twenty-one percent of the 279 girls studied showed symptoms of AN. Analysis of the food intake showed that calories, calcium and iron were below the recommendations of the Standing Committee on the Specific Evaluation of Dietary Reference Intakes (DRI Committee) and the National Research Council, while protein and carbohydrate were within the recommended range and fat was above the percentage of recommended total energy intake. Compared to girls without symptoms, they had a significantly smaller intake of calories and iron, and a higher intake of protein. Findings shown in this paper point out the need for intervention in adolescents because their dieting behavior can predispose to an eating disorder.

Women with high scores for cognitive dietary restraint choose foods lower in fat and energy

Women with high dietary restraint typically report restricting energy intake and using reduced-kilocalorie foods in an effort to achieve or maintain a certain body weight. However, previous studies of food choices associated with dietary restraint have been limited by the self-report of participants' food selections. We provided all foods consumed during a free-living 24-hour period to 62 normal-weight women with high (n=33) or low (n=29) dietary restraint, and observed choices from among similar foods varying in fat, fiber, and energy content. Women with high dietary restraint consumed less energy and chose reduced-kilocalorie and reduced-fat foods more frequently than unrestrained eaters. Group differences in choices of milk, cream cheese, mayonnaise, salad dressing, and soda were noted. Dietitians may consider frequent use of reduced-kilocalorie and reduced-fat foods a potential indicator of high dietary restraint, which may have health consequences. Accordingly, further exploration of clients' tendency to restrict dietary intake may be warranted.

Weight-control behaviors among adolescent girls and boys: implications for dietary intake

OBJECTIVE

To examine associations between healthful and unhealthful weight-control behaviors and dietary intake among adolescents.

DESIGN

Cross-sectional survey (Project EAT [Eating Among Teens]).Subjects/Setting The study population included 4144 middle and high school students from Minneapolis/St. Paul public schools from diverse racial and socioeconomic backgrounds. Statistical analyses Dietary intake patterns were compared across adolescent girls and boys reporting unhealthful, only healthful, or no weight-control behaviors in unadjusted analyses and analyses adjusted for sociodemographic factors and energy intake.

RESULTS

Among girls, mean intakes differed across weight-control behaviors for all foods and nutrients examined. P values ranged from P=.006 to P<.001. Girls using unhealthful weight-control behaviors had significantly lower intakes of fruit; vegetables; grains; calcium; iron; vitamins A, C, and B-6; folate; and zinc than girls using only healthful weight-control behaviors. Compared with girls reporting no weight-control behaviors, girls using unhealthful weight-control behaviors had lower intakes of grains, calcium, iron, vitamin B-6, folate, and zinc. In contrast to the girls, boys reporting unhealthful weight-control behaviors did not have poorer dietary intakes than boys not using weight-control behaviors or using only healthful behaviors. Among boys, there were no significant differences in mean intakes of vegetables; grains; calcium; iron; vitamins A, C, and B-6; folate; and zinc. Furthermore, boys using unhealthful weight-control behaviors had higher fruit intakes (P=.002) than boys reporting no weight-control behaviors.

CONCLUSIONS

Adolescent girls who engage in unhealthful weight-control behaviors are at increased risk for dietary inadequacy. The findings demonstrate a need for interventions to prevent unhealthful weight-control behaviors in adolescent girls, and to promote healthful weight-control behaviors when indicated.