Impact of Fasting on Food Craving, Mood and Consumption in Bulimia Nervosa and Healthy Women Participants

Try not to think about food: An association between fasting, binge eating and food cravings

BACKGROUND

When individuals follow a diet or limit their food intake, they activate cognitive restraint, which is defined as a mental effort to restrict dietary behavior with the goal of losing weight. As an example, fasting has also been associated with the recruitment of cognitive restraint, but further research is needed to fully understand its underlying mechanisms.

AIMS

The aim of this study was to examine the relationship between the duration of fasting and disordered eating, such as food cravings, binge eating, and potential changes in eating habits.

METHODS

An online survey was conducted among 853 first-semester university students to investigate their fasting practices and frequency over a three-month period prior to data collection. Participants who were on diets were excluded (n=214). After controlling the sample for biases, a comparison was made between 89 fasters and 369 non-fasters. The study compared levels of cognitive restraint, binge eating, food cravings, and consumption of 'forbidden' foods. A Poisson model was used to examine the association between hours of fasting and disordered eating traits. In the context of this study, the rate ratio was used to examine the relationship between fasting hours and disordered eating characteristics, such as binge eating and food cravings.

RESULTS

The study found that fasters experienced an increase in food cravings and binge eating. However, fasters consumed fewer bread slices than non-fasters. The rate ratio of fasting hours practiced is 115% higher among binge eaters (RR 2.15; CI95% 1.70-2.73) compared to those who did not binge. The rate ratio of fasting hours is 29% higher in participants with moderate binge eating (RR 1.29; CI95% 1.05-1.59), increasing to 140% (RR 2.40; CI95% 1.86-3.11) in people with severe binge eating. As for food cravings (state), the rate ratio was 2% higher (RR 1.02; CI 95% 1.01-1.03) for each increase in the unit of the scale.

CONCLUSIONS

Our study has indicated that fasting is positively associated with increased levels of binge eating and food cravings.

Identifying factors that predict the onset and persistence of fasting for weight control: Prospective findings

OBJECTIVE

Fasting for weight control is an under-studied behaviour implicated in eating disorders. However, little is known about what factors account for its onset and persistence.

METHOD

This study sought to identify risk and maintenance factors for fasting among 1025 women recruited through an eating disorder self-help platform who completed study measures at baseline and 6 month follow-up. Univariate and multivariate logistic regressions were performed to test which variables at baseline predicted the onset (vs. stably asymptomatic) and persistence (vs. remission) of fasting at follow-up.

RESULTS

Univariate models showed that higher baseline overvaluation, dissatisfaction, fear of weight gain, generalised and social anxiety, depression, self-esteem deficits and eating disorder symptoms (inflexible eating rules, driven exercise) predicted greater likelihood of fasting onset. Only fear of weight gain and depressive symptoms remained significant in the multivariate model. Higher baseline overvaluation, fear of weight gain, driven exercise, inflexible eating rules, and depression predicted greater likelihood of fasting persistence in univariate models. An adherence to inflexible eating rules and overvaluation remained significant in the multivariate model.

CONCLUSION

Findings shed new light on factors that may account for the development and maintenance of fasting, which have implications for guiding effective interventions targeting this behaviour.

Fasting diets: what are the impacts on eating behaviors, sleep, mood, and well-being?

Fasting diets (FDs) have drawn great attention concerning their contribution to health and disease over the last decade. Despite considerable interest in FDs, the effect of fasting diets on eating behaviors, sleep, and mood-essential components of diet satisfaction and mental health- has not been addressed comprehensively. Understanding the critical role that fasting plays in these elements will open up potential treatment avenues that have not yet been explored. The aim of the present paper was to conduct a comprehensive critical review exploring the effects of fasting on eating behaviors, sleep, and mood. There is currently a lack of clarity regarding which fasting option yields the most advantageous effects, and there is also a scarcity of consistent trials that assess the effects of FDs in a comparable manner. Similarly, the effects and/or treatment options for utilizing FDs to modify eating and sleep behaviors and enhance mood are still poorly understood. Further researches aiming at understanding the impacts of various fasting regimes, providing new insights into the gut-brain axis and offering new treatment avenues for those with resistant anxiety and depression, are warranted. Alteration of eating behaviors can have lasting effects on various physiological parameters. The use of fasting cures can underpin ancient knowledge with scientific evidence to form a new approach to the prevention and treatment of problems associated with co-morbidities or challenges pertaining to eating behaviors. Therefore, a thorough examination of the various fasting regimens and how they impact disease patterns is also warranted.

Longitudinal transactions between negative urgency and fasting predict binge eating

Fasting and negative urgency (the disposition to act rashly when distressed) are risk factors for binge eating. It may be that each influences the other over time to predict binge eating.

OBJECTIVE

This study tested whether (1) fasting predicts binge eating through negative urgency, and (2) negative urgency predicts binge eating through fasting.

METHOD

Path analysis and mediation tests were used to investigate objectives in n = 302 college women assessed three times over eight months. We controlled for each variable at the previous time point, and concurrent negative affect and body mass index at each time point.

RESULTS

Time 1 (T1) fasting predicted elevated negative urgency three months later at Time 2 (T2) and T2 negative urgency predicted increases in binge eating five months later at Time 3 (T3). T2 negative urgency mediated the relationship between T1 fasting and T3 binge eating. T1 negative urgency predicted increases in T2 fasting, which then predicted increases in T3 binge eating. T2 fasting mediated the relationship between T1 negative urgency and T3 binge eating.

DISCUSSION

Findings suggest fasting and negative urgency transact to predict binge eating among college women. Interventions targeting negative urgency may prevent or reduce both fasting and binge eating.

Very low-calorie ketogenic diet in the treatment of adaptive thermogenesis: A case report

OBJECTIVES

The management of the phenomenon of adaptive thermogenesis poses a challenge to the successful treatment of overweight/obesity with a nutritional intervention that minimizes the loss of muscle mass, with little cognitive restraint use and disorganization of eating behavior. On the other hand, it creates a significant calorie deficit for the reduction of body fat. The aim of this case report was to discuss the effects of a very low-calorie ketogenic diet in a woman with obesity and low resting metabolic rate.

CASE DESCRIPTION

A 36-y-old white woman with a history of obesity and bulimia nervosa who has had difficulty losing and maintaining weight despite numerous dietary and pharmacologic treatments.

RESULTS

There was a loss of 12 kg in 115 d, reaching 13.4 kg, with 11.4 kg of fat mass (FM). The resting metabolic rate showed an increase of 79% in relation to the initial rate, reaching normal levels for the predictive equations and maintaining this level in the first-year follow-up. Additionally, improvement of metabolic laboratory parameters and eating behavior traits were described.

CONCLUSIONS

In this specific case of bulimia nervosa resulting in hypometabolism (low resting metabolic rate/fat-free mass) and obesity, the very low-calorie ketogenic diet intervention has demonstrated a possibility of weight loss with little cognitive restraint use, thereby increasing resting metabolic rate in the short and medium terms, ultimately promoting a negative energy balance. In relation to the numeric results, it seems positive; however, more research is necessary to evaluate the effects on the overall relationship with food and its long-term repercussions.

Effectiveness of intermittent fasting for weight loss in individuals with obesity: A meta-analysis of randomized controlled trials

AIM

To assess whether intermittent fasting (IF) diets are associated with improvement in weight loss, metabolic parameters, and subjective well-being, in people with obesity.

DATA SYNTHESIS

We performed a Meta-analysis of Randomized Controlled Trials longer than 2 months, retrieved through an extensive search on MedLine, Cochrane CENTRAL Library, and Embase online databases, comparing weight loss with IF diets and control diets in people with Body Mass index (BMI) > 30 kg/m². We retrieved 9 trials, enrolling 540 patients. IF was not associated with a significantly greater reduction of body weight or BMI at any time point with respect to controls or in respect to continuous restricted diets, with low-to moderate quality of evidence; no significant difference in efficacy between alternate day fasting and time restricted eating was found. Differences in fasting plasma glucose, total or high-density lipoprotein cholesterol or blood pressure at any time point were not statistically significant, whereas a reduction of low-density lipoprotein cholesterol (MD -8.39 [-15.96, -0.81] mg/dl, P = 0.03; I² = 0%) was observed at 2-4 months, but not in the longer term. Data on psychological parameters and overall well-being were insufficient to perform a formal meta-analysis, whereas a qualitative synthesis did not show any difference between IF and controls.

CONCLUSIONS

IF is not associated with greater or lesser weight loss than non-intermittent fasting diets. Further data on psychological parameters and overall well-being are needed to properly assess the role of IF diets in the management of obesity.

Examining the role of urgency in predicting binge size in bulimia nervosa

Greater binge size within bulimia nervosa is associated with elevated distress and impairment. Theoretical models posit that emotion dysregulation predicts binge eating, but little research has investigated the potential for dispositional traits that reflect difficulty in emotion regulation to predict binge size among women with bulimia nervosa. Research supports that negative urgency, the tendency to act rashly when feeling distressed, is associated with binge eating behavior among individuals with bulimia nervosa. Relatively fewer studies have explored associations between binge eating and positive urgency, the tendency to act rashly when feeling extreme positive affect. The urgency traits may predict greater binge size within bulimia nervosa. The current study sought to examine negative urgency and positive urgency as predictors of test meal intake in a sample of 50 women, n = 21 with bulimia nervosa and n = 29 healthy controls. Dispositional levels of positive urgency, negative urgency, positive affect, and negative affect were measured prior to a laboratory binge eating paradigm. Participants in the bulimia nervosa group scored higher on negative urgency, positive urgency, and negative affect than participants in the control group. Across participants, lower levels of negative affect were associated with greater test meal intake. Elevated levels of positive urgency predicted significantly greater test meal intake, but only for participants with bulimia nervosa. No other dispositional traits predicted test meal intake when the interaction of positive urgency and group was included in the model. Findings suggest positive urgency is an underappreciated, but potentially important, risk factor for greater binge size in bulimia nervosa.

Emotional and external eating styles associated with obesity

BACKGROUND

Obesity is related to eating habits. Overeating is the most behavioural trait implicated in obesity; emotional, external and rigid restrained eating are three maladaptive eating habits that are associated to overeating.

OBJECTIVES

The current study assesses the eating styles of Algerian adults. It identifies and analyses differences in eating styles in a sample from adults with normal BMI and who have obesity. The study examines the relationship between eating styles and BMI.

METHODS

The sample consisted of 200 volunteers aged from 31 to 62 years old, 110 with obesity and 90 having normal BMI. The participants were recruited from hospital and university employees. They were questioned about their eating habits. The participants did not receive any treatment. To assess eating styles, participants completed the DEBQ.

RESULTS

The prevalence of women was in the majority, representing 61% (n = 122) in the total sample (63.63% (n = 70) with obesity, and 55.77% (n = 52) with normal BMI). The prevalence of men represents 39% (n = 78) in the total sample (36.36% (n = 40) with obesity, and 42.22% (n = 38) with normal BMI). Participants with obesity showed pathological eating styles. They scored higher on emotional and external eating styles than to normal BMI group. However, restraint eating showed a slight no significant increase. The mean scores ± standard deviations observed in each eating styles were: emotional eating (2.88 ± 0.99** vs. 1.71 ± 0.32), external eating (3.31 ± 0.68** vs. 1.96 ± 0.29), and retrained eating (1.81 ± 0.7^ns vs. 1.3 ± 0.30). The linear regression analysis showed an effect of emotional and external eating on BMI.

CONCLUSION

These results could be used to provide clinical information at the initial screening for obesity criteria, obesity prevention and treatment.

Adverse childhood experiences and disordered eating among middle-aged adults: Findings from the coronary artery risk development in young adults study

Adverse childhood experiences (ACEs) include childhood abuse, neglect, and household substance abuse. Childhood abuse is a risk factor for disordered eating (DEB). Less well established are associations of childhood neglect and household substance abuse with DEB, and little research has examined ACE associations with DEB in middle adulthood. The objective of this study was to examine associations between ACEs and DEBs among middle-aged adults and examine sex differences. ACEs prior to age 18 were retrospectively assessed in the Coronary Artery Risk Development in Young Adults study in 2000-2001 (N = 3340, ages 32 to 46). DEB outcomes (i.e., concerns about weight and shape, anxiety about eating or food, unhealthy weight control behaviors, chronic dieting, overeating, and binge eating) were assessed in 1995-1996 (ages 27 to 41). Modified Poisson regressions estimated risk ratios (RRs) for associations of a history of any ACE, each ACE, and cumulative ACEs with DEB outcomes. Among women, emotional abuse, physical neglect, and emotional neglect were each modestly associated with most DEBs (RRs = 1.21-1.35, 1.21-1.45, and 1.23-1.41 across DEBs, respectively) after adjustment for sociodemographic variables, BMI, and depressive symptoms. A cumulative ACE score was associated with all DEBs in a stepwise manner (p for trend ≤0.05) except concerns about weight and shape and overeating. Among men, emotional abuse was most consistently related to the majority of DEBs (RRs = 1.23-1.92); household substance abuse was modestly associated with overeating (RR = 1.26, 95% CI = 1.04-1.53). ACEs were cumulatively associated with unhealthy weight control behaviors, overeating, and binge eating (p for trend <0.01).

The Effect of Fasting on Human Metabolism and Psychological Health

Fasting is a prevalent approach to weight loss and is a feasible method for treating some diseases, such as type 2 diabetes. Meanwhile, the effects of intermittent fasting on health, aging, and disease process are hot issues and are of concern by researchers of multiple areas, even the public. This article introduces the effects of fasting on human lipid metabolism, glucose metabolism, protein metabolism, and neuroendocrine metabolism; demonstrates the metabolic conversion caused by fasting; and describes the effects of fasting on human psychological health, the relationship between mood regulation and glucose, and the emotional enhancing effect induced by fasting.

Hunger increases negative and decreases positive emotions in women with a healthy weight

The term 'hangry' is colloquially used to describe being "bad tempered or irritable as a result of hunger," but remarkably few studies have examined the effect of hunger on emotions. Yet, women attempting to restrict their food intake may be at risk of becoming entangled in a vicious cycle of hunger and negative emotions. That is, hunger may lead to negative emotions, which can lead to overeating and overeating can, in turn, provoke subsequent restriction leading to more hunger. Therefore the aim of this study was to examine the effect of hunger on positive and negative emotions in women with a healthy BMI, and the role of subclinical eating disorder symptoms in this effect. We randomly assigned women to a hunger condition (fasting for 14 h, n = 53) or satiated condition (eat breakfast before the study, n = 55), and they completed the Eating Disorder Examination Questionnaire and the Profile of Mood States in the lab. Hungry women reported overall higher negative emotions (higher tension, anger, fatigue, and confusion) and lower positive emotions (lower vigour and marginally lower esteem-related affect) than satiated women. Moreover, for satiated but not for hungry women, higher eating disorder symptoms were associated with lower esteem-related affect. These findings show that food restriction leads to negative emotions, and practitioners and individuals should be aware of these implications of food restriction on mental health. Second, clinicians and individuals should be wary of relatively low esteem-related affect when satiated in individuals with eating disorder symptoms, as it could serve as a maintaining factor in eating pathology.

The ATP Level in the mPFC Mediates the Antidepressant Effect of Calorie Restriction

Food deprivation can rescue obesity and overweight-induced mood disorders, and promote mood performance in normal subjects. Animal studies and clinical research have revealed the antidepressant-like effect of calorie restriction, but little is known about the mechanism of calorie restriction-induced mood modification. Previous studies have found that astrocytes modulate depressive-like behaviors. Inositol 1,4,5-trisphosphate receptor type 2 (IP3R2) is the predominant isoform in mediating astrocyte Ca2+ signals and its genetic knockout mice are widely used to study astrocyte function in vivo. In this study, we showed that deletion of IP3R2 blocked the antidepressant-like effect induced by calorie restriction. In vivo microdialysis experiments demonstrated that calorie restriction induced an increase in ATP level in the medial prefrontal cortex (mPFC) in naïve mice but this effect disappeared in IP3R2-knockout mice, suggesting a role of astrocytic ATP in the calorie restriction-induced antidepressant effect. Further experiments showed that systemic administration and local infusion of ATP into the mPFC induced an antidepressant effect, whereas decreasing ATP by Apyrase in the mPFC blocked calorie restriction-induced antidepressant regulation. Together, these findings support a role for astrocytic ATP in the antidepressant-like effect caused by calorie restriction.

How Experiences Affect Psychological Responses During Supervised Fasting: A Preliminary Study

As an unusual event, fasting can induce strong physiological and psychological reactions, but there is still no clear understanding of how previous fasting experiences affect people’s responses to current fasting. This study aimed to investigate the influence of previous fasting experiences on participants’ basic physiological and psychological responses in a fasting experiment conducted under intensive medical monitoring. For a 22-day experiment divided into four phases (3-day Baseline; 10-day Complete Fasting; 4-day Calorie Restriction; and 5-day Recovery phases), a total of 13 persons participated; the participants were divided into a group with prior fasting experience (Experienced: N = 6) and a group without prior fasting experience (Newbie: N = 7). The results indicate no group differences in physiological responses (i.e., weight, glucose, and ketone bodies); however, differences in psychological states were observed, with the Newbie group showing more negative psychological states overall throughout the experiment (i.e., greater appetite, more negative mood states, more stress, less vitality, and fewer recovery resources). Hence, previous fasting experience may be a buffer against negative feelings during current fasting. For this reason, it is important to consider fasting experiences as a vital factor in future research.

The Psychology of Food Cravings: the Role of Food Deprivation

PURPOSE OF REVIEW

Dieting is often blamed for causing food cravings. Such diet-induced cravings may be mediated by physiological (e.g., nutritional deprivation) or psychological (e.g., ironic effects of food thought suppression) mechanisms. However, this notion is often based on cross-sectional findings and, thus, the causal role of food deprivation on food cravings is unclear.

RECENT FINDINGS

Experimental studies suggest that a short-term, selective food deprivation seems to indeed increase cravings for the avoided foods. However, experimental studies also show that food craving can be understood as a conditioned response that, therefore, can also be unlearned. This is supported by intervention studies which indicate that long-term energy restriction results in a reduction of food cravings in overweight adults. Dieting's bad reputation for increasing food cravings is only partially true as the relationship between food restriction and craving is more complex. While short-term, selective food deprivation may indeed increase food cravings, long-term energy restriction seems to decrease food cravings, suggesting that food deprivation can also facilitate extinction of conditioned food craving responses.

Mechanisms and Effects of Dietary Restriction on CNS and Affective Disorders

Neuropsychiatric disorders, including depression contribute significantly to global disability and possess high social and health burden. Management is dominated by pharmacotherapy and psychotherapy; nevertheless, such treatments prevent or treat less than half of the patients, suggesting that alternative approaches are required. Emerging data suggest that diet may be an adjustable risk factor for psychiatric disorders. Caloric restriction (CR) possesses protective effects in almost all organs including the brain. However, the precise molecular pathways of these effects remain uncertain. In this review, we will discuss the putative neurobiological mechanisms of CR on the brain. The article will address also the molecular basis of the antidepressant effects of CR, primarily including ghrelin signaling, CREB neurotropic effects and ketone bodies production. Then we will highlight the probable effect of CR on the neuroinflammation, which emerges as a key pathogenetic factor for the majority of neuropsychiatric disorders. Finally, we discuss the so called caloric restriction mimetics, compounds that reproduce properties of CR. Further research will be required to verify the safety and efficacy of CR before a general approval can be proposed to introduce it and its mimetics in clinical practice for the treatment of neuropsychiatric disorders.

Testing virtual reality-based cue-exposure software: Which cue-elicited responses best discriminate between patients with eating disorders and healthy controls?

PURPOSE

Virtual reality (VR) technologies have been proposed as a new tool able to improve on in vivo exposure in patients with eating disorders. This study assessed the validity of a VR-based software for cue exposure therapy (CET) in people with bulimia nervosa (BN) and binge eating disorder (BED).

METHODS

Fifty eight outpatients (33 BN and 25 BED) and 135 healthy participants were exposed to 10 craved virtual foods and a neutral cue in four experimental virtual environments (kitchen, dining room, bedroom, and cafeteria). After exposure to each VR scenario, food craving and anxiety were assessed. The frequency/severity of episodes of uncontrollable overeating was also assessed and body mass index was measured prior to the exposure.

RESULTS

In both groups, craving and anxiety responses when exposed to the food-related virtual environments were significantly higher than in the neutral-cue virtual environment. However, craving and anxiety levels were higher in the clinical group. Furthermore, cue-elicited anxiety was better at discriminating between clinical and healthy groups than cue-elicited craving.

CONCLUSIONS

This study provides evidence of the ability of food-related VR environments to provoke food craving and anxiety responses in BN and BED patients and highlights the need to consider both responses during treatment. The results support the use of VR-CET in the treatment of eating disorder patients characterized by binge-eating and people with high bulimic symptoms.

Anxiety symptoms and emotional eating are independently associated with sweet craving in young adults

Sweet craving (SC), defined as a strong desire for sweet foods, seems to be closely related to negative emotions, such as anxiety and unhealthy eating behaviors. The objective was to investigate factors that are associated with SC and to assess the relationships among SC, anxiety symptoms, and eating behavior in university students. This was a cross-sectional study involving 300 students of both sexes (20.5 ± 4.4 years) who were freshmen in a Brazilian public university. Eating behavior was evaluated using the Three Factor Eating Questionnaire, anxiety symptoms were assessed using the Beck Anxiety Inventory, SC was identified by a yes/no question ("Have you had a very strong desire to eat sweet food over the last three months?"), and characterized by the Questionnaire for Assessment of Sweet Substance Dependence. Individuals with SC scored significantly higher for uncontrolled eating (UE), emotional eating (EE), and anxiety symptoms. Logistic regression analysis revealed that anxiety symptoms are independently associated with SC. In conclusion, negative emotions, like anxiety, and eating guided by these emotions can contribute to the SC phenomenon.

Behavioral and neurodevelopmental precursors to binge-type eating disorders: support for the role of negative valence systems

BACKGROUND

Pediatric loss-of-control (LOC) eating is a robust behavioral precursor to binge-type eating disorders. Elucidating precursors to LOC eating and binge-type eating disorders may refine developmental risk models of eating disorders and inform interventions.

METHOD

We review evidence within constructs of the Negative Valence Systems (NVS) domain, as specified by the Research Domain Criteria framework. Based on published studies, we propose an integrated NVS model of binge-type eating-disorder risk.

RESULTS

Data implicate altered corticolimbic functioning, neuroendocrine dysregulation, and self-reported negative affect as possible risk factors. However, neuroimaging and physiological data in children and adolescents are sparse, and most prospective studies are limited to self-report measures.

CONCLUSIONS

We discuss a broad NVS framework for conceptualizing early risk for binge-type eating disorders. Future neural and behavioral research on the developmental trajectory of LOC and binge-type eating disorders is required.

Dimensions of emotion dysregulation in anorexia nervosa and bulimia nervosa: A conceptual review of the empirical literature

Several existing conceptual models and psychological interventions address or emphasize the role of emotion dysregulation in eating disorders. The current article uses Gratz and Roemer's (2004) multidimensional model of emotion regulation and dysregulation as a clinically relevant framework to review the extant literature on emotion dysregulation in anorexia nervosa (AN) and bulimia nervosa (BN). Specifically, the dimensions reviewed include: (1) the flexible use of adaptive and situationally appropriate strategies to modulate the duration and/or intensity of emotional responses, (2) the ability to successfully inhibit impulsive behavior and maintain goal-directed behavior in the context of emotional distress, (3) awareness, clarity, and acceptance of emotional states, and (4) the willingness to experience emotional distress in the pursuit of meaningful activities. The current review suggests that both AN and BN are characterized by broad emotion regulation deficits, with difficulties in emotion regulation across the four dimensions found to characterize both AN and BN, although a small number of more specific difficulties may distinguish the two disorders. The review concludes with a discussion of the clinical implications of the findings, as well as a summary of limitations of the existing empirical literature and suggestions for future research.

The Effects of Calorie Restriction in Depression and Potential Mechanisms

Depression, also called major depressive disorder, is a neuropsychiatric disorder jeopardizing an increasing number of the population worldwide. To date, a large number of studies have devoted great attention to this problematic condition and raised several hypotheses of depression. Based on these theories, many antidepressant drugs were developed for the treatment of depression. Yet, the depressed patients are often refractory to the antidepressant therapies. Recently, increasing experimental evidences demonstrated the effects of calorie restriction in neuroendocrine system and in depression. Both basic and clinical investigations indicated that short-term calorie restriction might induce an antidepressant efficacy in depression, providing a novel avenue for treatment. Molecular basis underlying the antidepressant actions of calorie restriction might involve multiple physiological processes, primarily including orexin signaling activation, increased CREB phosphorylation and neurotrophic effects, release of endorphin and ketone production. However, the effects of chronic calorie restriction were quite controversial, in the cases that it often resulted in the long-term detrimental effects via inhibiting the function of 5-HT system and decreasing leptin levels. Here we review such dual effects of calorie restriction in depression and potential molecular basis behind these effects, especially focusing on antidepressant effects.