Definition of emotion regulation

ER is a growing field within psychology and holds a central role in all the psychological areas including health, development, clinical, social and personality as well as in a variety of other disciplines⁽ Reference Gross ^{34 )}. ER can be broadly defined as the set of strategies used to maintain a positive affective status or improve or suppress a negative affective status in stressful and non-stressful circumstances⁽ Reference Compas, Jaser and Dunbar ^{35 ,} Reference Gross ^{36 )}. Nevertheless, there is no single, unified approach of ER. One of the first definitions was given by Thompson⁽ Reference Thompson ^{37 )}, who defined ER as ‘the extrinsic and intrinsic process by which individuals are able to monitor, evaluate and modify their emotions to accomplish their goal’⁽ Reference Thompson ^{37 )}. This concept has been amplified to describe a process for modifying and maintaining feelings, behaviours and psychological features of emotions. In other words, ER refers to attempts to influence which emotions one has and how one experiences or expresses these emotions⁽ Reference Gross ^{34 ,} Reference Gross ^{38 )}. Also, the Adaptive Coping with Emotions (ACE) model has explained how emotion dysregulation can occur and provided tools to enhance effective ER⁽ Reference Berking and Whitley ^{39 )}. This new model is based on the acquisition of skills which help to maintain or restore mental health and to address aversive emotions. To summarise, ER is a common process that depends on certain skills and is frequently used in daily life to ensure personal well-being.

Psychological factors related to emotion regulation

ER is related to and interacts with other psychological factors. According to Gross⁽ Reference Gross ^{34 )}, ER along with coping and mood regulation concepts shape the affective regulation term. Coping is understood as responses to alleviate stress, whereas ER is conceptualised as an ongoing process that occurs under both stressful and non-stressful circumstances and is organised around specific emotions (i.e. sadness, fear, anger) and includes efforts to up- or down-regulate both positive and negative emotions⁽ Reference Compas, Jaser and Dunbar ^{35 ,} Reference Gross ^{36 )}. In contrast, mood refers to less specific and longer-lasting experiences and seems to be influenced by cognition more than by behaviour processes. Mood regulation may be distinguished from ER by its predominant focus on altering subjective feeling states⁽ Reference Gross ^{34 )}. Therefore, it is suggested that there is a considerable overlap among these regulatory processes⁽ Reference Gross ^{34 )}.

Other factors are executive functions, which are important in the management of cognitive and behavioural processes including working memory, reasoning, task flexibility, inhibition capacity and impulsivity, problem solving, planning and execution⁽ Reference Royall, Lauterbach and Cummings ^{40 )}. Some studies have reported a direct link between executive function abilities and specific ER capacities⁽ Reference Gyurak, Goodkind and Kramer ^{41 )}. Interestingly, impairments of executive function have been reported in overweight adults⁽ Reference Fitzpatrick, Gilbert and Serpell ^{42 )} and also in children⁽ Reference Schwartz, Leonard and Perron ^{43 ,} Reference Blanco-Gómez, Ferré and Luque ^{44 )} since it might contribute to eating styles⁽ Reference Groppe and Elsner ^{45 )}. Indeed, childhood disorders characterised by impaired executive function, such as attention-deficit/hyperactivity disorder, are associated with overeating and obesity⁽ Reference Dempsey, Dyehouse and Schafer ^{46 ,} Reference Erhart, Herpertz-Dahlmann and Wille ^{47 )}.

Self-regulation is a key factor related to ER and executive function that can be understood to include effortful control and impulsivity control. The concept of effortful control encompasses the abilities to inhibit or activate behaviours for the benefit of long-term goals; impulsivity is characterised by high reward sensitivity and a high deficit of response inhibition. These factors have a direct relationship with dietary restraint, in which efforts are made to suppress reward-based impulses to eat in pursuing long-term weight goals⁽ Reference Johnson, Pratt and Wardle ^{48 )}. Several studies in children have found that an increase in impulsivity, a decrease in inhibitory control and a higher reward sensitivity are associated with unhealthier food choices and overweight⁽ Reference Batterink, Yokum and Stice ^{49 –} Reference Pauli-Pott, Albayrak and Hebebrand ^{53 )}.

Emotion regulation in children

Childhood and adolescence are two critical periods in the development of executive function, behaviour-regulation skills and consequently ER strategies. However, newborns and infants are capable of regulating their emotions. From the first days of life, using a neonatal self-regulation assessment, individual differences have been found in controlling negative emotions in a stressful environment⁽ Reference Perez-Pereira, Fernandez and Gómez-Taibo ^{54 )}. At preschool age, children acquire a large range of strategies to manage their own mood and this ability is established in adolescence⁽ Reference Zeman, Cassano and Perry-Parrish ^{55 )}.

Parental influence is essential in the process of ER development, where parents serve as role models and influence the family atmosphere⁽ Reference Morris, Silk and Steinberg ^{56 )}. Children learn ER skills early through interactions with their parents or caregivers, as well as through family factors like family expressivity or communication⁽ Reference Gresham and Gullone ^{57 )}. Also, a negative parental response to children’s emotions teaches children to avoid rather than understand emotions and has been linked to inappropriate ER strategies⁽ Reference Jones, Eisenberg and Fabes ^{58 )}. Parenting styles characterised by ‘high warmth and high control’ have an influence on children’s effective ER leading to greater self-efficacy, self-discipline and successful dealing with challenges⁽ Reference Morris, Silk and Steinberg ^{56 ,} Reference Baumrind, Larzelere and Owens ^{59 )}.

ER is essential to healthy psychological functioning. In children, it is an important predictor of risk behaviours⁽ Reference Dickstein and Leibenluft ^{60 ,} Reference Wills, Pokhrel and Morehouse ^{61 )} and mental problems⁽ Reference Dickstein and Leibenluft ^{60 )}, particularly those related to emotional problems⁽ Reference Braet, Theuwis and Van Durme ^{62 )}. Children who do not develop adequate ER strategies will be less able to survive in new environments where they face conflicts. The use of maladaptive ER can generate a vicious circle, since it may increase negative emotions which are involved in developing maladaptive strategies⁽ Reference Berking and Whitley ^{39 )}.

Emotion regulation skills

According to the theory of adaptive coping cited above⁽ Reference Berking and Whitley ^{39 )}, adaptive ER is conceptualised as a situation-dependent interaction between ER skills. The regulatory skills in this model are: awareness of emotions (i.e. the ability to identify and label emotions), understanding emotions (i.e. the ability to identify the causes and maintaining factors of emotions); acceptance and tolerance (i.e. the ability to accept and tolerate negative emotions when necessary); self-support and self-compassion (i.e. the ability to provide effective self-support and self-compassion in distressing situations by self-soothing, self-encouragement and active self-coaching); modifying emotions (i.e. the ability to modify emotions in an adaptive way, which includes self-efficacy) and readiness to confront (i.e. the ability to address situations likely to cause negative emotions). Enhancing or acquiring these skills helps in maintaining or restoring mental health and in approaching aversive emotions⁽ Reference Berking, Poppe and Luhmann ^{63 )}.

Physiological mechanisms leading to obesity

Studies have shown that stress can increase overweight and the related adverse metabolic consequences through neuroendocrine changes⁽ Reference Pervanidou and Chrousos ^{72 )}. Repeated activation of the hypothalamic–pituitary–adrenal (HPA) axis mediates stress responses and increases cortisol secretion. This chronic cortisol hypersecretion may cause fat to accumulate in the visceral adipose tissues⁽ Reference Charmandari, Tsigos and Chrousos ^{73 )} through interaction with lipid homeostasis at several levels: lipolysis, adipogenesis, lipogenesis, and the regulation of circulating fatty acids⁽ Reference Peckett, Wright and Riddell ^{74 )}. However, intense acute or chronic stress might also lead to hypo-activation of the HPA axis, or hypocortisolism⁽ Reference Pervanidou and Chrousos ^{72 )}. The cortisol response to stress is complex, but both hypo- and hypercortisolism may be harmful. According to a meta-analysis, HPA activity depends on the personal response to stress, since cortisol output increases with distress and decreases in individuals with post-traumatic acute stress⁽ Reference Miller, Chen and Zhou ^{75 )}. Recent research in schoolchildren indicates that stress is associated with hypercortisolism⁽ Reference Michels, Sioen and Braet ^{76 )}. Additionally, other findings point out that maladaptive ER induces cortisol reactivity⁽ Reference Cris, Opre and Miu ^{77 )}.

Therefore, stress in combination with maladaptive coping strategies could lead to dysregulated cortisol secretion and obesity. Since cortisol is appetite-stimulating, it also increases appetite and the attraction to sweet and fatty foods, mainly by stimulating reward pathways or by influencing other hormones⁽ Reference Michels, Sioen and Braet ^{76 ,} Reference Dallman, Pecoraro and Akana ^{78 )}.

Emotional eating: a mediator between emotional dysregulation and obesity

Lifestyle: a mediator between emotional dysregulation and obesity

Stress and negative affect are linked to other aspects of obesity-related lifestyle like sedentary behaviour and low physical activity. Children and adolescents with stress or negative affect may perform less physical activity due to decreased motivation and are likely to spend more time on sedentary activities like video games, Internet and television⁽ Reference Ouwens, Cebolla and van Strien ^{98 ,} Reference Anton, Newton and Sothern ^{116 ,} Reference Reeves, Postolache and Snitker ^{117 )}. A recent review suggests that cognitive abilities and self-regulation may enhance active or inactive physical activity behaviours⁽ Reference Buckley, Cohen and Kramer ^{118 )}. Indeed, a failure in ER or self-regulation might predispose to sedentary behaviour whereas successful self-regulation has been associated with more physical activity⁽ Reference Isasi, Ostrovsky and Wills ^{65 ,} Reference Isasi and Wills ^{66 )}. Simultaneously, an individual could perform physical activity to deal with stressful states or negative emotions. In a representative Canadian sample (aged 15 years or over), 40 % reported using exercise for stress coping and these individuals were more likely to use positive coping strategies and less likely to use alcohol or drugs for coping⁽ Reference Cairney, Kwan and Veldhuizen ^{119 )}. Physical activity could play a role as an adaptive coping strategy and also increase well-being and efficient ER skills in adults⁽ Reference Hegberg and Tone ^{120 )} and adolescents⁽ Reference Ho, Louie and Chow ^{121 )}. This effect could be possible through neuro-hormonal mechanisms but also psychological and sociological aspects⁽ Reference Monshouwer, ten Have and van Poppel ^{122 ,} Reference Rees and Sabia ^{123 )}.

Concurrently, stress and disturbed affective states may influence sleep patterns, causing difficulties in falling asleep or sleep disruption⁽ Reference Morin, Rodrigue and Ivers ^{124 ,} Reference Vandekerckhove, Weiss and Schotte ^{125 )}. Indeed, a comprehensive review described the bidirectional relationship between stress and sleep problems and their underlying pathways⁽ Reference Kahn, Sheppes and Sadeh ^{126 )}. Ineffective ER strategies appear to be related to sleep disturbances, which reduce sleep quantity and quality. Since sleep problems may be associated with diminished self-regulation of appetite, they can increase the risk of overeating and obesity⁽ Reference Kahn, Sheppes and Sadeh ^{126 ,} Reference Burt, Dube and Thibault ^{127 )}. In the other direction, sleep also plays a role in regulating cognitive and emotional processes. Poor sleep may negatively affect the ability of perception, processing and understanding emotional stimuli⁽ Reference Kahn, Sheppes and Sadeh ^{126 ,} Reference Alfarra, Fins and Chayo ^{128 )}. A recent laboratory study showed that sleep loss affects adequate attention resources during an emotional task⁽ Reference Alfarra, Fins and Chayo ^{128 )}. As a consequence, adequate sleep patterns could ameliorate negative emotions and be helpful in ER.

Interventions in adults

Several intervention studies and randomised controlled trials have recently been conducted in adults to test the effectiveness of ER strategies in regulating obesity and food intake⁽ Reference O’Reilly, Cook and Spruijt-Metz ^{129 )}. The most frequent strategies are based on the regulatory skills and correspond to new approaches within the cognitive–behavioural psychological therapies. So, mindfulness therapy, acceptance and commitment therapy, self-compassion therapy (loving-kindness therapy), emotionally focused therapy and dialectical behaviour therapy lead to less psychological distress⁽ Reference Compare, Calugi and Marchesini ^{130 –} Reference Mantzios and Wilson ^{134 )}, fewer binge eating episodes⁽ Reference Compare, Calugi and Marchesini ^{130 ,} Reference Dalen, Smith and Shelley ^{131 ,} Reference Wiser and Telch ^{135 )}, less emotional eating⁽ Reference Alberts, Thewissen and Raes ^{136 )}, fewer food cravings⁽ Reference Alberts, Thewissen and Raes ^{136 –} Reference Forman, Hoffman and Juarascio ^{138 )}, healthier eating patterns⁽ Reference Dalen, Smith and Shelley ^{131 ,} Reference Miller, Kristeller and Headings ^{139 )}, weight loss⁽ Reference Dalen, Smith and Shelley ^{131 ,} Reference Forman, Butryn and Hoffman ^{132 ,} Reference Mantzios and Wilson ^{134 ,} Reference Forman, Hoffman and Juarascio ^{138 )}, fewer personal barriers to physical activity⁽ Reference Tapper, Shaw and Ilsley ^{140 )}, and improved self-efficacy to weight loss⁽ Reference Kidd, Graor and Murrock ^{141 )}. Despite a few non-significant findings⁽ Reference Kearney, Milton and Malte ^{142 )}, these strategies are a promising approach for obesity treatment and prevention.

Mechanisms of intervention

Mindfulness therapy encourages individuals to be non-judgmentally aware of and to understand their emotions so that they can avoid maladaptive ER such as emotional eating⁽ Reference Alberts, Mulkens and Smeets ^{137 )}. Acceptance therapy could reduce frustration and food preoccupation because it increases the ability to tolerate aversive internal experiences (i.e. anger or sadness)⁽ Reference Forman, Butryn and Hoffman ^{132 )}. Similarly to these therapies, dialectical behaviour therapy and emotionally focused therapy enhance identification, enabling individuals to accept and modify emotions adaptively. Self-compassion therapy is related to self-support and can help to reduce the sense of threat and stimulate a self-soothing system⁽ Reference Gilbert and Procter ^{143 )}.

The skills used in the several types of therapies are interrelated, and other individual positive factors should be encouraged simultaneously, such as self-empathy, self-esteem, assertiveness, self-efficacy and resilience. For example, self-compassion and mindfulness are related to lower self-criticism since they enhance self-kindness, self-acceptance, self-empathy and self-esteem⁽ Reference Berking and Whitley ^{39 )}. Through self-empathy, we develop a concern for our well-being, learn to be sensitive and tolerant of our distress, and develop a deep understanding of its roots and causes. Self-empathy is negatively associated with negative affect and stress and could help us to deal with weight and food stress in a non-judgemental/critical way and to develop self-warmth⁽ Reference Gilbert and Procter ^{143 )}. Self-esteem also could be a mediator between emotional disorders and obesity⁽ Reference Cortese, Falissard and Angriman ^{144 )}, since low self-esteem in childhood predicts weight gain⁽ Reference Ternouth, Collier and Maughan ^{24 )}. So, good self-esteem could help to enhance self-encouragement and self-coaching, which enables individuals to modify their emotions and to confront negative situations. Along with these skills, assertiveness could be developed and be useful as a strategy of social relation, self-confidence and coping. The ability to analyse and actively modify emotions improves emotional self-efficacy, which reduces stress and avoidance of aversive events. In addition, resilience, which is the capacity to deal successfully with disturbances, is related to awareness, acceptance and tolerance; it decreases vulnerability to negative emotion and boosts self-regulation abilities (i.e. impulse control). This emotional resilience and self-efficacy facilitates a disposition to experience emotionally challenging situations with additional opportunities to strengthen ER skills⁽ Reference Berking and Whitley ^{39 )}. Later, Forman & Butyn⁽ Reference Forman and Butryn ^{145 )} considered the acceptance-based intervention efficacious for weight control in individuals who are more susceptible to eating in response to internal and external cues (for instance, availability of unhealthy food). These skills included an ability to tolerate uncomfortable internal responses and a reduction of pleasure, behavioural commitment to clearly defined values, and conscience of decision-making process⁽ Reference Forman and Butryn ^{145 )}.

Interventions in children

Systematic reviews of interventions show that successful childhood obesity interventions should be multidimensional, combining traditional strategies with behavioural and psychological approaches⁽ Reference Waters, de Silva-Sanigorski and Hall ^{2 )}. Nevertheless, few interventional studies have focused on emotional factors. One recent review of behavioural interventions reported that only a small number of intervention studies focused on stress management and emotional control training but that these studies were generally effective⁽ Reference Martin, Chater and Lorencatto ^{146 )}. The latter-mentioned ER techniques have been applied in children and adolescents in the field of mental disorders but not in child obesity. Nevertheless, we have highlighted some intervention studies which could use methods with similar features of ER techniques such as calm down and awareness about feelings and deal with emotion in a healthy way.

In the field of childhood obesity prevention focusing on ER, to our knowledge there is only one pilot study and two on-going studies⁽ Reference Riggs, Sakuma and Pentz ^{147 –} Reference Melnyk, Kelly and Jacobson ^{149 )}. A school-based pilot intervention translated specific components of a violence and substance abuse programme into a lifestyle intervention. This pilot programme included seven lessons focusing on teaching tools for controlling impulsiveness, recognising and adaptively dealing with stress, and analysing the effectiveness of possible solutions⁽ Reference Riggs, Sakuma and Pentz ^{147 )}. Although it was a short-term and non-randomised controlled study, the result was a significant change in positive attitudes toward self-regulation of appetite and positive changes in food and lifestyle⁽ Reference Riggs, Sakuma and Pentz ^{147 )}. A randomised clinical trial and prospective study conducted in 779 adolescents and their parents applied a cognitive–behavioural skills intervention combined with nutrition education and physical activity. The programme included four of fifteen sessions on cognitive reappraisal, emotional and behavioural regulation, stress, coping, goal-setting and overcoming barriers to a healthy lifestyle⁽ Reference Melnyk, Kelly and Jacobson ^{149 )}. This intervention indicated a positive impact on physical activity, BMI and psychological outcomes and also after 6 months, the participants had lower BMI⁽ Reference Melnyk, Jacobson and Kelly ^{150 )}. Another school-based intervention study is currently being carried out in toddlers, combining a traditional obesity prevention programme with a programme to enhance self-regulation. The study teaches children tools for behavioural self-regulation and includes a parental intervention⁽ Reference Miller, Horodynski and Herb ^{148 )}.

In childhood obesity treatment, successful intervention studies have applied cognitive–behavioural therapy to encourage the development of effective ER⁽ Reference Boutelle, Kuckertz and Carlson ^{151 –} Reference Moore, Borawski and Cuttler ^{157 )}. One pilot interventional study applied a cognitive–behavioural skills-building programme in primary care services. The programme was carried out through seven telephone and clinical sessions, which included evaluation of emotional responses and behaviour. Although their results did not show an effect on BMI, they observed an increase in physical activity, healthy lifestyle behaviours and nutrition knowledge. Long-term results were mainly attained in children with supportive families⁽ Reference Jacobson and Melnyk ^{153 ,} Reference Jacobson and Melnyk ^{154 )}. Another interventional study conducted in thirty-one children aged 6–12 years and their parents showed positive persistent results since anthropometric parameters and energy intake were reduced and family habits and emotional and social problems were improved at 5 years follow-up⁽ Reference Vignolo, Rossi and Bardazza ^{152 )}. Although these studies did not include a control group, their results are promising. Indeed, Sacher et al. ⁽ Reference Sacher, Kolotourou and Chadwick ^{156 )} developed a randomised controlled trial through a multicomponent community-based childhood obesity intervention based on nutritional and behavioural change in 160 obese children and their parents. The intervention showed a reduction in waist circumference and BMI at 6 and 12 months post-intervention. Therefore, both clinical and community settings now support the development of childhood obesity programmes using ER-related skills.

Implications for prevention

Given that the acquisition of healthy ER and dietary habits starts in infancy, prevention strategies should be implemented early in life and target the promotion of mental health, effective ER techniques and healthy lifestyle habits such as eating behaviour. Learning effective ER skills from an early age (i.e. as awareness and understanding emotions, acceptance of emotional distress and to learn to have a tolerance under frustration and negative feelings) could avoid children acquiring and developing maladaptive ER such as emotional eating when they feel overwhelmed by intense emotions or stressful events. These intervention approaches should be applied along with nutritional interventions through family-based community programmes, in primary care or in schools. Since parenting style and parental modelling influence children’s ER and lifestyle, community obesity prevention programmes should provide support to parents for teaching conflict and negative emotion management techniques and also seek to actively involve parents and family members in changing their own behaviour. To integrate this approach into the school setting, teachers can act as health agents and ER, along with healthy eating habits and lifestyle, can be incorporated into the school curriculum. This type of curricular programme should focus on learning and encouraging awareness and understanding of feelings, identifying internal strengths and learning effective ER skills. Of course, ER programmes should be adapted to the children’s age and should include working groups for parents, to reinforce the concepts and techniques that children learn in class and to help the parents face difficult situations they may encounter with their children. One such novel ER approach has been proposed for a school-based obesity prevention programme⁽ Reference Sakuma, Riggs and Pentz ^{158 ,} Reference Pentz ^{159 )}.

Implications for treatment

In obesity treatment, public health agents and paediatricians are encouraged to consider traditional weight-loss methods and nutritional recommendations along with ER intervention. Through ER-based intervention, barriers in the treatment progress such as shame and preoccupation with food can be targeted by fostering greater self-soothing, self-esteem, resilience and body acceptance. Additionally, families need to be aware of the emotional distress that overweight children suffer from. Consequently, the family should also be involved in the intervention to learn effective ER and how to resolve potential conflicts with the child.