INTRODUCTION

“Dietary restraint behavior refers to conscious attempts to reduce food intake to control body weight”¹. Although it has been reported that restraint may be an effective strategy in controlling body weight², some studies have indicated that excessive restriction may have negative outcomes, such as overeating and weight gain^1,3.

Different individual and psychosocial variables may impact dieting behavior in childhood and adolescence⁴, including sociocultural pressure to be thin^4,5,6 and individual characteristics such as increased weight status or body mass index (BMI)⁷. Forrester-Knauss et al⁷ and Balantekin et al⁴ stressed that a higher BMI may cause restricted eating. This is especially important as the global number of children and adolescents (5-19 years old) who are obese has grown tenfold between 1975 and 2016. In 2016, 213 million children and adolescents were overweight⁸.

Although several factors impact adolescent eating behaviors, family is an important influence^9,10,11. Increasing evidence indicates that a higher frequency of family meals are associated with a healthy diet¹², a lower likelihood of obesity or being overweight¹³, better family interaction and communication¹² and increased adolescent well-being^3,13,14,15. At the same time, it has been reported that a low frequency of family meals may predict extreme weight control behaviors in adolescents^6,12. These behaviors negatively affect adolescent diet quality^13,16 and well-being. In addition, some studies have shown that parents can promote the development of child dieting behavior by conveying to the child that being thin is important to his or parents, by verbally encouraging dieting or by modeling their own dieting behaviors⁵. Controlling food-related parenting practices such as food restriction may also be used¹⁷. Although it is well established that both mothers and fathers influence their children's eating behavior, it is also well known that their influence differs¹¹. Some studies have shown that both parents are engaged in practices that promote healthy eating and an adequate BMI in their adolescent children^6,12 while others have suggested that mothers exert greater influence on their daughters and fathers on their sons¹⁰. There is also evidence suggesting that the mother's role is more relevant^{5,6,11,12,18,19}.

Some studies have reported that dietary restraint is related to lower levels of life satisfaction in adolescents and emerging adults²⁰ while others have reported no association between dietary restraint and life satisfaction²¹. Similarly, dietary restraint has been also associated with lower levels of satisfaction in the food domain in adolescents and university students^20,22,23. In addition, researchers have suggested that individuals with eating disorders are impaired in other important domains of their lives, such as in social relationships²². This may be relevant for adolescents as family relationships are among the factors most closely related to adolescent life satisfaction^11,24.

In several dietary restraint studies, participants have been divided into classes of chronic dieters and non- dieters based on a conventional cutoff point. This method has been criticized since dividing study participants into dichotomous groups may lead to a loss of variability and may mask associations of different behavioral combinations^4,20,25. Thus, some authors have used empirical classifications, such as cluster analysis or latent class analysis, to examine subgroups of dieters and weight management strategies in samples of female adolescents^4,25, adults and emerging adults of both genders^20,26 and among young males²². However, to the best of our knowledge, only one available study has considered a sample of adolescents of both genders¹³. This study distinguished three profiles in Finnish adolescents: unbalanced weight control, adverse habits and healthy lifestyle. Therefore, more research is needed in order to distinguish different profiles of adolescents of both genders according to their dietary restraint behavior. Although girls and female adolescents are more prone to dietary restraint¹⁶ and usually have higher values of restrained eating than boys⁷, the relationship between higher BMI and dietary restraint exists in adolescents of both genders⁷. Furthermore, recent studies have suggested that “the gap between male and female individuals in dietary restraint may be narrowing”^22,23.

In this context, the objectives of this study were: a) to identify adolescent profiles based on dietary restraint behavior b) to determine if these profiles differed in terms of adolescent diet quality, nutritional status, life satisfaction, and satisfaction with family life and food-related life, and c) to determine if these profiles differed in terms of family characteristics, mother dietary restraint, diet quality and nutritional status.

MATERIAL AND METHODS

RESULTS

DISCUSSION

This study focused on identifying adolescent profiles based on dietary restraint behavior to determine if these profiles differed in terms of adolescent diet quality, nutritional status, life satisfaction or satisfaction with family life and food-related life, and to determine if these profiles differed in terms of family characteristics, maternal dietary restraint, diet quality and nutritional status. The results of the LCA yielded two classes: “non-dieters” (class 1, 52.44%) and “dieters” (class 2, 47.56%). Dieters had a higher mean age, a higher proportion of overweight and obesity and lower scores on the satisfaction with life and food-related life. Families from the dieters class had a lower frequency of family dinners. Their mothers had higher weight fluctuations and higher rates of obesity.

During adolescence, body image and dieting concerns are common and often associated with an increased desire to be accepted as having attained the idealized cultural image of beauty, which is often associated with thin or lean bodies⁶. This leads adolescents of both genders to adopt behaviors related to dietary restraint¹⁶. This is the first study that has identified adolescent profiles of both genders based on participant responses to the RRS using LCA. Contrary to what was expected, only two adolescent profiles were detected. This finding contradicts the results obtained by Kachi²⁵ in Japan and Balantekin et al⁴ in the U.S. which used LCA on samples of female adolescents as well as those reported by Peterson et al²⁶ with an adult sample of both genders in the U.S. All of these authors identified three or more different profiles in terms of dieting behaviors. Kachi²⁵ identified “unhealthy dieters” (27%), “healthy dieters” (39%) and “non-dieters” (34%). Balantekin et al⁴ identified the following profiles: “non-dieters” (26%), “lifestyle” (16%, characterized by a high probability of reporting increasing exercise and eating more fruits and vegetables for weight control, both health-promoting lifestyle changes), “dieters” (43%), and “extreme dieters” (17%). Peterson et al²⁶ identified profiles characterized by “dietary restraint only” (51%), “low dietary restraint” (27%) and “dietary restraint plus psychopathology” (22%). In addition, our results contradict previous findings reported in Chile using the RRS that used a hierarchical cluster analysis and identified four profiles in a sample of undergraduate students of both genders²⁰: “unconcerned about diet and weight fluctuations” (53.8%), “concerned about dieting” (18.7%), “concerned about weight fluctuations” (17.1%), and “concerned about diet and weight fluctuations” (10.6%). Three profiles were also identified in a sample of male undergraduate students²¹: “unconcerned about diet and weight fluctuations” (40.3%), “concerned about diet and weight fluctuations” (37.0%) and “concerned about weight fluctuations” (22.7%). These differences may be related to the gender and age composition of the samples, cultural factors and/or the instrument used to measure dietary restraint. All of these variables require further research.

It is worth noting that the RRS mean scores of the “non-dieters” and “dieters” classes match the cutoff commonly used to classify “non-dieters” and “chronic dieters”¹. Regardless, the results obtained using LCA allowed the more common diet concern behaviors and weight fluctuations in the “dieters” class to be identified (Table 3). Contrary to previous studies associating overweight, obesity and dietary restraint with a low diet quality1^3,16, adolescents and mothers from “dieters” and “non-dieters” did not differ in their diet quality. Therefore, the higher presence of overweight and obese adolescents and obese mothers in the “dieters” class may be explained by considering other determinants of obesity, such as physical activity¹⁵, which deserves more attention in future studies. Nevertheless, these results confirm the need for Chilean families to modify their eating habits^3,11,14,15, since both classes had low AHEI scores.

The greater proportion of overweight and obese adolescents and obese mothers in the “dieters” class is consistent with studies that have linked higher BMIs to increased dietary restraint in adolescents and adults of both genders^21,22,28. This may be the case of unsuccessful dieters, who are characterized by high restraint and a high tendency toward overeating²⁰. Nevertheless, other authors have suggested that a higher BMI would not only be an outcome of restrained eating, but may also predict restrained eating in adolescents of both genders^4,7. Thus, further research is needed to understand the association between BMI and dietary restraint in mothers and their adolescent children. However, the higher proportion of overweight and obese adolescents and obese mothers in the “dieters” class could explain the use of food restriction by these mothers. Berge et al¹⁷ found that when the parent and the adolescent were both overweight/obese, the parent engaged in high levels of food restriction, which may induce both overeating and dietary restraint in the adolescent¹⁰. In a sample of young children, Haycraft et al⁹ similarly found that overweight/obese mothers reported controlling their children's eating more often, but modeled healthy eating less. These behaviors may be potential pathways for the intergenerational transmission of obesity and dietary restraint from mother to child⁹.

Regarding adolescent well-being, the significantly lower SWLS scores from the “dieters” class confirm previous findings showing that lower levels of life satisfaction are associated with dietary restraint²⁰ and obesity²² in university students. Lower SWFoL scores of the “dieters” class is also supported by studies that have reported that dietary restraint is associated with lower levels of well-being in the food domain in samples of university students^20,22. However, the lack of statistical differences between the “dieters” and “non-dieters” classes on the SWFaL would confirm that dietary restraint is not associated with satisfaction with family life²³, although family eating habits^6,17, food-related parenting practices¹⁷ and parents' dieting behaviors⁵ have been related to weight control behaviors in adolescents. In this regard, Schnettler, Miranda-Zapata et al²³ explain these results by suggesting that adolescent assessment of family life satisfaction does not consider either food-related or dietary aspects. However, another possible explanation may be related to the mean ages of the classes (higher mean age of “dieters”) given that it has been reported that adolescent well-being decreases during adolescence in both genders, but not in the same way as it does across all life domains²⁴.

Another unexpected result was the lack of statistical differences in the gender composition of both classes, which contradicts previous studies that found that female adolescents are more likely to engage in dietary restraint than male adolescents^7,16. However, our findings confirm previous studies that have suggested that “the gap between male and female individuals in dietary restraint may be narrowing”^22,23. Our findings may also be related to the increasing rates of obesity and overweight among children and adolescents of both genders⁸ worldwide, as an increased weight status or BMI has been linked to increased dieting behaviors in adolescents of both genders⁷. Therefore, our results support the need for further research on dietary restraint in male samples^21,22,23, but especially in male adolescent samples.

Regarding family meals, our results contradict evidence showing that a high frequency of family meals is associated with healthier diets¹². Even though “non-dieters” had a higher frequency of shared dinners with their family than “dieters”, the two classes did not differ in their diet quality. However, the greater frequency of family dinners in the “non-dieters” is in line with studies that have reported that a higher frequency of family meals is associated with a lower likelihood of obesity or overweight¹³ as well as higher well- being in adolescents^3,13,14,15. This is because more frequent family meals lead to more connected, communicative and supportive families, which in turn may lead to more positive experiences¹². Also, our results confirm that a higher frequency of family meals is associated with a lower likelihood of dietary restraint in adolescents^6,12. Therefore, frequent family meals should be promoted in families with adolescent children to improve their well-being and also to prevent dietary restraint behaviors.

In addition, the main difference between the mothers of the “dieters” and “non-dieters” classes was the higher WF score among mothers in the “dieters” class. Therefore, it is possible that, regardless of the mother's diet concern, the mother's weight fluctuations are related to their adolescent children's exercise of dietary restraint, regardless of gender. Although this result contradicts the previous findings that the eating characteristics of male adolescents are unrelated to those of their mothers¹⁰, it partially agrees with the results reported by Francis and Birch¹⁸, who found that mothers that were more preoccupied with their own weight made more attempts to influence their daughters' weight, thereby leading them to practice dietary restraint. This may also be the case with male and female adolescents in the “dieters” class due to the increased prevalence of overweight and obesity in adolescents of both genders⁸. However, our results support those reported by van den Berge et al¹⁷, specifically the finding that greater maternal concern regarding weight is related to an increase in weight loss attempts in adolescents of both genders.

The main limitations of this study include its cross- sectional design and the non-probabilistic nature of the sample, which limits the generalization of our results. Responses may also have been affected by social desirability as all data were self-reported. Indeed, self-reported eating habits may be affected by an overestimation of the frequency of healthy food consumption and an underestimation of the frequency of unhealthy food consumption, especially in the “dieters” class as reported in previous studies⁴. The same underestimation may occur in self-reported weight. Another potential limitation is that we did not consider the ways mothers pressure their children to be thin or the food-related parenting practices used to promote weight loss. Since the sample included adolescents from both dual-headed and single-headed households, the influence of fathers was also not measured. All of these variables should be addressed in future studies.

Despite these limitations, this study shows that there is a high prevalence of dietary restraint in adolescents regardless of gender, which is concerning given the increasing prevalence of obesity and overweight in adolescents in Chile and the prevalence of low diet quality at the national level. Dietary restraint in the studied sample was related to higher adolescent and mother BMIs, greater mother weight fluctuations, a lower frequency of family meals and lower levels of life satisfaction and satisfaction with food-related life in adolescents. Therefore, interventions intended to reduce obesity/overweight and dietary restraint in adolescents, as well as those aimed at improving their levels of subjective well-being, must include both the mother and the adolescent child, regardless of gender.