Changes in Food Cravings and Eating Behavior after a Dietary Carbohydrate Restriction Intervention Trial

Understanding the experiences of ketogenic metabolic therapy for people living with varying levels of depressive symptoms: a thematic analysis

Background

Evidence suggests that a ketogenic diet (KD) may help to alleviate psychiatric symptoms, including depression and anxiety. Positive changes have been reported such as improvements in cognition, concentration, and sleep, a reduction in hunger, and an increase in well-being, energy, confidence, and resilience. This research aims to understand the impact of a non-calorie-restricted KD on depression and aspects of psychological well-being in those with varying degrees of depressive symptoms. Though there are a few studies directly exploring the experiences of those following a KD, this will be the first study to explore the narrative from a mental health and psychological well-being viewpoint.

Method

A sample of nine participants who had followed a non-calorie restricted KD intervention of 50 g of carbohydrates or less per day for at least 12 weeks were recruited. Participants were split into 'healthy adults' group who had no to low depressive symptoms and 'depressive symptoms' group who had mild to moderate depressive symptoms. A reflexive thematic analysis was considered suitable for this study.

Findings

Five core themes and 24 subthemes were created. These were, (1) Poor health prior to program; (2) Hunger and cravings-the food and mood connection; (3) Psychological well-being improvements; (4) It becomes a lifestyle; and (5) Implementation difficulties. Participants experienced mental health improvements such as increased self-esteem, confidence, motivation, and achievement. Some experienced more control in life and a greater sense of reward. Those with depressive symptoms who initially reported low self-worth and hopelessness later reported increased self-esteem and renewed meaning and purpose in life. The findings from this study reflect the previous reports that the diet implementation can be difficult initially, but soon becomes easy to follow and turns into a lifestyle.

Conclusion

In the literature, there are very few qualitative studies that explore the accounts and lived experiences of those following a KD. From the participants' accounts in this study, it appears that the benefits and positive outcomes of this diet outweigh any negative side-effects experienced. This is encouraging for those who are looking for adjunctive therapies to address and improve their depressive symptoms and overall mental health.

Acute and two-week effects of neotame, stevia rebaudioside M and sucrose-sweetened biscuits on postprandial appetite and endocrine response in adults with overweight/obesity-a randomised crossover trial from the SWEET consortium

BACKGROUND

Sweeteners and sweetness enhancers (S&SE) are used to replace energy yielding sugars and maintain sweet taste in a wide range of products, but controversy exists about their effects on appetite and endocrine responses in reduced or no added sugar solid foods. The aim of the current study was to evaluate the acute (1 day) and repeated (two-week daily) ingestive effects of 2 S&SE vs. sucrose formulations of biscuit with fruit filling on appetite and endocrine responses in adults with overweight and obesity.

METHODS

In a randomised crossover trial, 53 healthy adults (33 female, 20 male) with overweight/obesity in England and France consumed biscuits with fruit filling containing 1) sucrose, or reformulated with either 2) Stevia Rebaudioside M (StRebM) or 3) Neotame daily during three, two-week intervention periods with a two-week washout. The primary outcome was composite appetite score defined as [desire to eat + hunger + (100 - fullness) + prospective consumption]/4.

FINDINGS

Each formulation elicited a similar reduction in appetite sensations (3-h postprandial net iAUC). Postprandial insulin (2-h iAUC) was lower after Neotame (95% CI (0.093, 0.166); p < 0.001; d = -0.71) and StRebM (95% CI (0.133, 0.205); p < 0.001; d = -1.01) compared to sucrose, and glucose was lower after StRebM (95% CI (0.023, 0.171); p < 0.05; d = -0.39) but not after Neotame (95% CI (-0.007, 0.145); p = 0.074; d = -0.25) compared to sucrose. There were no differences between S&SE or sucrose formulations on ghrelin, glucagon-like peptide 1 or pancreatic polypeptide iAUCs. No clinically meaningful differences between acute vs. two-weeks of daily consumption were found.

INTERPRETATION

In conclusion, biscuits reformulated to replace sugar using StRebM or Neotame showed no differences in appetite or endocrine responses, acutely or after a two-week exposure, but can reduce postprandial insulin and glucose response in adults with overweight or obesity.

FUNDING

The present study was funded by the Horizon 2020 program: Sweeteners and sweetness enhancers: Impact on health, obesity, safety and sustainability (acronym: SWEET, grant no: 774293).

Influence of anti-obesity strategies on brain function in health and review: A review

The aim of this review was to investigate in the literature the application of strategies such as low carbohydrate diet (LCD), ketogenic diet (KD) and intermittent fasting (IF) and their effects on the CNS. We performed a narrative review of the literature. The search was specifically carried out in PubMed, selecting articles in English, which had the following keywords: obesity, central nervous system, low carb diet, ketogenic diet and intermittent fasting, using the narrative review methodology. The studies found show that the benefits of the LCD, KD and IF strategies, at the CNS level, have a strong influence on the mechanisms of hunger and satiety, as well as on the reduction of food reward and show improvement in memory and mood influenced by the interventions.

Acute and repeated impact of sweeteners and sweetness enhancers in solid and semi-solid foods on appetite: protocol for a multicentre, cross-over, RCT in people with overweight/obesity - the SWEET Project

INTRODUCTION

Intake of free sugars in European countries is high and attempts to reduce sugar intake have been mostly ineffective. Non-nutritive sweeteners and sweetness enhancers (S&SEs) can maintain sweet taste in the absence of energy, but little is known about the impact of acute and repeated consumption of S&SE in foods on appetite. This study aims to evaluate the effect of acute and repeated consumption of two individual S&SEs and two S&SE blends in semisolid and solid foods on appetite and related behavioural, metabolic and health outcomes.

METHODS AND ANALYSIS

A work package of the SWEET Project; this study consists of five double-blind randomised cross-over trials which will be carried out at five sites across four European countries, aiming to have n=213. Five food matrices will be tested across three formulations (sucrose-sweetened control vs two reformulated products with S&SE blends and no added sugar). Participants (body mass index 25-35 kg/m²; aged 18-60 years) will consume each formulation for 14 days. The primary endpoint is composite appetite score (hunger, inverse of fullness, desire to eat and prospective food consumption) over a 3-hour postprandial incremental area under the curve during clinical investigation days on days 1 and 14.

ETHICS AND DISSEMINATION

The trial has been approved by national ethical committees and will be conducted in accordance with the Declaration of Helsinki. Results will be published in international peer-reviewed open-access scientific journals. Research data from the trial will be deposited in an open-access online research data archive.

TRIAL REGISTRATION NUMBER

NCT04633681.

Craving for carbs: food craving and disordered eating in low-carb dieters and its association with intermittent fasting

Studies point to positive outcomes in a diet with reduction of carbohydrates and that the associated practice of intermittent fasting (IF) might increase weight loss. Although dieting might be related to disordered eating, little evidence is available about the role of restrictive carbohydrates diets on disordered eating. This study aimed to explore if doing low-carb (LC) diets was related to disordered eating and if IF would increase these symptoms. The sample comprised university students (n = 682), with a mean age of 22 years old and average BMI of 23.6 kg/m2 (SD = 4.3). Twenty-seven percent (n = 188) of respondents reported doing LC diet in the last three months. Of those, 31% (n = 58) reported doing LC diet combined with periods of IF. Mean scores were compared using parametric tests, and effects size and correlations between variables were calculated. Dieters showed higher levels of binge eating, food cravings, cognitive restraint, cognitive restraint toward carbohydrates when compared to non-dieters. The association of LC and IF was related to an increase in disordered eating, especially binge eating and food cravings, specifically 'Lack of control', 'Thoughts or preoccupation with food,' and 'Guilt from cravings and/or for giving in to them'. These results provide evidence that restrictive carbohydrate diets and IF may increase cognitive restraint and, consequently, food cravings.Level III: Evidence obtained from cohort or case-control analytic studies.

Effect of a Low-Carbohydrate Diet With or Without Exercise on Anxiety and Eating Behavior and Associated Changes in Cardiometabolic Health in Overweight Young Women

Background

The effectiveness of low-carbohydrate diets (LCDs) on weight loss and exercise for improving cardiometabolic fitness have been well documented in the literature, but the effects of LCDs and whether adding exercise to a LCD regime could additionally benefit mental health (e. g., by lowering the level of anxiety) and associated changes in eating behavior are less clear in overweight and obese populations. Therefore, this study aimed to investigate the effects of a 4-week LCD with or without exercise on anxiety and eating behavior, and to explore the associations between changes in the psychological state and physiological parameters (i.e., body composition, aerobic fitness, blood pressure, lipid profile, and metabolic hormones).

Methods

Seventy-four overweight Chinese women [age: 20.8 ± 3.0 years, body mass index (BMI): 25.3 ± 3.3 kg·m⁻²] completed the 4-week randomized controlled trial, which included a LCD group (i.e., ~50 g daily carbohydrate intake) with exercise training 5 days/week (LC-EXE, n = 26), a LCD group without exercise training (LC-CON, n = 25) and a control group that did not modify their habitual diets and physical activity (CON, n = 23). Levels of anxiety, eating behavior scores and physiological parameters (i.e., body weight, V̇O_2peak, blood pressure, fasting glucose, blood lipids, and serum metabolic hormones including insulin, C-peptide, leptin, and ghrelin) were measured before and after the intervention.

Results

There were significant reductions in anxiety levels in the LC-EXE compared with the LC-CON group, while no statistical changes were found in eating behaviors in any conditions after the 4-week intervention. Significant reduction in weight (~3.0 kg or 4%, p < 0.01) and decreases in insulin (~30% p < 0.01), C-peptide (~20% p < 0.01), and leptin (~40%, p < 0.01) were found in both LC-CON and LC-EXE groups, but adding exercise to a LCD regime generated no additional effects. There were significant improvements in V̇O_2peak (~15% p < 0.01) and anxiety (~25% p < 0.01) in the LC-EXE compared with the LC-CON group, while no statistical differences were found between CON and LC-CON treatments. Further analysis revealed a negative association (r = −0.32, p < 0.01) between changes in levels of anxiety and changes in V̇O_2peak in all participates, no other correlations were found between changes in psychological and physiological parameters.

Conclusion

Although the combination of a LCD and exercise may not induce additional reductions in body weight in overweight young females, exercise could be a useful add-on treatment along with a LCD to improve cardiometabolic health and lower anxiety levels.

Alalwan T, Zahid MN, Spadaccini D, Gasparri C, Peroni G, Faragli A, Alogna A, La Porta E, Ali Redha A, Negro M, Cerullo G, D’Antona G, Rondanelli M. The Ketogenic Diet: Is It an Answer for Sarcopenic Obesity?

This review aims to define the effectiveness of the ketogenic diet (KD) for the management of sarcopenic obesity. As the combination of sarcopenia and obesity appears to have multiple negative metabolic effects, this narrative review discusses the effects of the ketogenic diet as a possible synergic intervention to decrease visceral adipose tissue (VAT) and fatty infiltration of the liver as well as modulate and improve the gut microbiota, inflammation and body composition. The results of this review support the evidence that the KD improves metabolic health and expands adipose tissue γδ T cells that are important for glycaemia control during obesity. The KD is also a therapeutic option for individuals with sarcopenic obesity due to its positive effect on VAT, adipose tissue, cytokines such as blood biochemistry, gut microbiota, and body composition. However, the long-term effect of a KD on these outcomes requires further investigations before general recommendations can be made.

Finding the Sweet Spot: Measurement, Modification, and Application of Sweet Hedonics in Humans

Sweetness is a sensation that contributes to the palatability of foods, which is the primary driver of food choice. Thus, understanding how to measure the appeal (hedonics) of sweetness and how to modify it are key to effecting dietary change for health. Sweet hedonics is multidimensional so can only be captured by multiple approaches including assessment of elements such as liking, preference, and consumption intent. There are both innate and learned components to the appeal of sweet foods and beverages. These are responsive to various behavioral and biological factors, suggesting the opportunity to modify intake. Given the high amount of added sugar intake in the United States and recommendations from many groups to reduce this, further exploration of current hypothesized approaches to moderate sugar intake (e.g., induced hedonic shift, use of low-calorie sweeteners) is warranted.

A healthy dietary pattern with a low inflammatory potential reduces the risk of gestational diabetes mellitus

Purpose

An optimal diet for lowering the risk of gestational diabetes mellitus (GDM) is still to be defined, but may comprise of nutrient intakes, dietary patterns, diet quality, and eating frequency. This study was designed to investigate the contribution of diet in developing GDM in a comprehensive way.

Methods

The dietary intake of overweight or obese women, a risk group for GDM (n = 351), was assessed using 3-day food diaries and diet quality questionnaires in early pregnancy. Eating frequency and nutrient intakes were calculated, and dietary patterns identified using principal component analysis. The inflammatory potential of the diet was determined by calculating the dietary inflammatory index (DII^®) and energy-adjusted DII (E-DII™). GDM was diagnosed with an oral glucose tolerance test at 24–28 gestational weeks.

Results

Higher adherence to ‘healthier dietary pattern’ characterized by consumptions of vegetables and rye bread associated with a reduced risk of GDM (adjusted OR 0.27, 95% CI 0.11–0.70). Higher E-DII score, indicating pro-inflammatory diet, was associated with a 27% higher risk of GDM (adjusted OR 1.27; 95% CI 1.08–1.49) for each E-DII point. In the evaluation of nutrient intakes, total fat, saturated fatty acids (SFAs), and trans fatty acids were higher and fiber lower in women developing GDM compared to women not developing GDM (all p < 0.05). Intakes of total fat, SFAs, and trans fatty acids were also significant predictors for GDM (all p < 0.05).

Conclusions

The results emphasize the importance of an overall healthy diet and limitation of foods with SFAs, and other nutrients with a high inflammatory potential in reducing the risk of GDM.

Trial registration

ClinicalTrials.gov Identifier: NCT01922791, August 14, 2013.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02749-z.

Ketogenic diets and appetite regulation

PURPOSE OF REVIEW

The popularity of ketogenic diets in the treatment of obesity has increased dramatically over the last years, namely due to their potential appetite suppressant effect. The purpose of this review was to examine the latest evidence regarding the impact of ketogenic diets on appetite.

RECENT FINDINGS

The majority of the studies published over the last 2 years adds to previous evidence and shows that ketogenic diets suppress the increase in the secretion of the hunger hormone ghrelin and in feelings of hunger, otherwise see when weight loss is induced by non-ketogenic diets. Research done using exogenous ketones point out in the same direction. Even though the exact mechanisms by which ketogenic diets suppress appetite remain to be fully determined, studies show that the more ketotic participants are (measured as β-hydroxybutyrate plasma concentration), the smaller is the increase in ghrelin and hunger and the larger is the increase in the release of satiety peptides. Further evidence for a direct effect of ketones on appetite comes from studies using exogenous ketones.

SUMMARY

The appetite suppressant effect of ketogenic diets may be an important asset for improving adherence to energy restricted diets and weight loss outcomes.

Cognitive restraint directed at carbohydrates in individuals on low-carb diet with binge eating: the role of guilt about food cravings

OBJECTIVE

To evaluate whether the carbohydrate-restricted diet leads to higher levels of food cravings in individuals with binge eating.

METHODS

A total of 146 individuals with binge eating participated in the Low-Carb Diet Group (n=48) and Control Group (n=98). The Binge Eating Scale, Hay's questionnaire, Food Cravings Questionnaire - Trait and State, Cognitive restraint subscale and its adapted version for the cognitive restraint toward carbohydrates, were used as measures. Parametric tests were used for comparison between groups (Student's t test), and Pearson's correlation test to verify correlations between variables of interest.

RESULTS

No differences were found between groups with and without diet concerning the level of binge eating or food craving total score. The differences found were the higher levels of cognitive restraint (p=0.01), cognitive restraint for carbohydrates (p=0.01) and subscales of 'guilt about food craving' (p=0.04) in the Low-Carb Diet Group.

CONCLUSION

Individuals with binge eating and a history of low-carb diet have greater cognitive restraint toward carbohydrates and association with altered eating attitudes (guilt about food craving).

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.