Change in self-efficacy, eating behaviors and food cravings during two years of calorie restriction in humans without obesity

When a calorie is not just a calorie: Diet quality and timing as mediators of metabolism and healthy aging

An epidemic of obesity has affected large portions of the world, increasing the risk of developing many different age-associated diseases, including cancer, cardiovascular disease, and diabetes. In contrast with the prevailing notion that "a calorie is just a calorie," there are clear differences, within and between individuals, in the metabolic response to different macronutrient sources. Recent findings challenge this oversimplification; calories from different macronutrient sources or consumed at different times of day have metabolic effects beyond their value as fuel. Here, we summarize discussions conducted at a recent NIH workshop that brought together experts in calorie restriction, macronutrient composition, and time-restricted feeding to discuss how dietary composition and feeding schedule impact whole-body metabolism, longevity, and healthspan. These discussions may provide insights into the long-sought molecular mechanisms engaged by calorie restriction to extend lifespan, lead to novel therapies, and potentially inform the development of a personalized food-as-medicine approach to healthy aging.

Nutrition literacy mediates the relationship between self-efficacy and eating behavior in young tuberculosis patients: A cross-sectional study

Objective

To assess the associations between self-efficacy, nutrition literacy and eating behavior, and to examine if nutrition literacy mediates the relationship between self-efficacy and eating behavior in young tuberculosis patients.

Methods

This cross-sectional study used a convenience sampling strategy to select 230 young tuberculosis patients at the Second Hospital of Nanjing (Public Health Medical Center of Nanjing), China, from June 2022 to August 2022. The data were collected using a demographic data form, the Eating Behavior Scale, the Food and Nutrition Literacy Questionnaire and the Tuberculosis Self-Efficacy Scale. Descriptive statistics, Pearson bivariate correlation analysis, Pearson partial correlation analysis, hierarchical multiple regression, and mediation analysis were conducted in the study.

Results

The mean self-efficacy score for young tuberculosis patients was 92.56 (SD = 9.89, range = 21 ∼ 105). The average nutrition literacy score for young tuberculosis patients was 68.24（SD = 6.75, range = 0 ∼ 100). The bivariate correlation analysis and partial correlation analysis found that self-efficacy was positively correlated with nutrition literacy (P < 0.01). The regression analysis showed that self-efficacy (F = 5.186, β = 0.233, P < 0.001)and nutrition literacy (F = 7.749, β = 0.545, P < 0.001) significantly predicted eating behavior. The three dimensions of nutrition literacy including nutritional knowledge (mediation effect ratio = 13.1%, 95% CI =  - 0.089; -0.005), preparing food (mediation effect ratio = 17.4%, 95 %CI = 0.011; 0.077) and eating (mediation effect ratio = 54.7%, 95 %CI = 0.070; 0.192) mediated the relationship between self-efficacy and eating behavior in young tuberculosis patients.

Conclusion

Nutrition literacy mediated the relationship between self-efficacy and eating behavior. To promote healthy eating behavior among young tuberculosis patients, interventions aimed at improving self-efficacy and nutrition literacy should be conducted.

Mediators of weight change in underserved patients with obesity: exploratory analyses from the Promoting Successful Weight Loss in Primary Care in Louisiana (PROPEL) cluster-randomized trial

BACKGROUND

Intensive lifestyle interventions (ILIs) stimulate weight loss in underserved patients with obesity, but the mediators of weight change are unknown.

OBJECTIVES

We aimed to identify the mediators of weight change during an ILI compared with usual care (UC) in underserved patients with obesity.

METHODS

The PROPEL (Promoting Successful Weight Loss in Primary Care in Louisiana) trial randomly assigned 18 clinics (n = 803) to either an ILI or UC for 24 mo. The ILI group received an intensive lifestyle program; the UC group had routine care. Body weight was measured; further, eating behaviors (restraint, disinhibition), dietary intake (percentage fat intake, fruit and vegetable intake), physical activity, and weight- and health-related quality of life constructs were measured through questionnaires. Mediation analyses assessed whether questionnaire variables explained between-group variations in weight change during 2 periods: baseline to month 12 (n = 779) and month 12 to month 24 (n = 767).

RESULTS

The ILI induced greater weight loss at month 12 compared with UC (between-group difference: -7.19 kg; 95% CI: -8.43, -6.07 kg). Improvements in disinhibition (-0.33 kg; 95% CI: -0.55, -0.10 kg), percentage fat intake (-0.25 kg; 95% CI: -0.50, -0.01 kg), physical activity (-0.26 kg; 95% CI: -0.41, -0.09 kg), and subjective fatigue (-0.28 kg; 95% CI: -0.46, -0.10 kg) at month 6 during the ILI partially explained this between-group difference. Greater weight loss occurred in the ILI at month 24, yet the ILI group gained 2.24 kg (95% CI: 1.32, 3.26 kg) compared with UC from month 12 to month 24. Change in fruit and vegetable intake (0.13 kg; 95% CI: 0.05, 0.21 kg) partially explained this response, and no variables attenuated the weight regain of the ILI group.

CONCLUSIONS

In an underserved sample, weight change induced by an ILI compared with UC was mediated by several psychological and behavioral variables. These findings could help refine weight management regimens in underserved patients with obesity.This trial was registered at clinicaltrials.gov as NCT02561221.

What helps to form a healthy nutrition habit? Daily associations of intrinsic reward, anticipated regret, and self-efficacy with automaticity

BACKGROUND

High automaticity in healthy nutrition behaviors is related to long-term maintenance of these behaviors. Drawing upon theoretical frameworks of habit formation, proposed antecedents such as intrinsic reward, anticipated regret, and self-efficacy are important correlates of automaticity, but not much is known about their day-by-day relationships with automaticity in healthy nutrition behaviors. This study tested previous-day within-person (i.e., from one day to the next) and same-day within-person associations of intrinsic reward, anticipated regret, and self-efficacy with automaticity of a healthy nutrition behavior, for which participants attempted to form a new habit.

METHODS

Secondary analyses of a randomized controlled trial with two planning intervention conditions including a longitudinal sample of n = 135 participants (age: M = 24.82 years; SD = 7.27) are reported. Participants formed a plan on a self-selected healthy nutrition behavior to become a new habit and were followed up over 12 weeks assessing daily levels of plan-specific intrinsic reward, anticipated regret, self-efficacy, and automaticity. Lagged multilevel models with 84 study days nested in participants estimated previous-day within-person, same-day within-person, and between-person relationships of intrinsic reward, anticipated regret, and self-efficacy with automaticity.

FINDINGS

Regarding within-level relationships, higher-than-usual levels of intrinsic reward, anticipated regret, and self-efficacy of the same day but not of the previous day were associated with higher within-person automaticity. With respect to between-level relationships, higher between-levels (i.e., higher person mean levels across the study period) of intrinsic reward, anticipated regret, and self-efficacy were linked with higher automaticity.

DISCUSSION

Findings point towards the potential to intervene on intrinsic reward, anticipated regret, and self-efficacy when aiming to promote a new healthy nutrition habit.

The Complicated Relationship between Dieting, Dietary Restraint, Caloric Restriction, and Eating Disorders: Is a Shift in Public Health Messaging Warranted?

The origins of theories specifying dietary restraint as a cause of eating disorders can be traced to the 1970s. This paper will present an overview of the origins of dietary restraint theories and a brief historical review of evidence will be summarized. Recent research will be presented, including the results from the CALERIE Phase 1 study, as well as CALERIE Phase 2, which were NIH-sponsored randomized controlled trials. CALERIE 2 provided a test of the effect of two years of caloric restriction (CR) on the development of eating disorder syndromes and symptoms in comparison to a control group that did not alter eating behavior or body weight. The intervention was effective for inducing a chronic (two-year) reduction in total energy expenditure and increased dietary restraint but did not increase symptoms of eating disorders. The results of this recent investigation and other studies have not provided experimental support for conventional dietary restraint theories of eating disorders. These findings are discussed in terms of potential revisions of dietary restraint theory, as well as the implications for a paradigm shift in public health messaging related to dieting.

French validation of the Weight Efficacy Life-Style questionnaire (WEL): Links with mood, self-esteem and stress among the general population and a clinical sample of individuals with overweight and obesity

Eating self-efficacy refers to a person’s belief in their ability to regulate eating. Although the Weight Efficacy Life-Style questionnaire (WEL) is one of the most widely used eating self-efficacy tools, its French validation is lacking. The objective of this research was to validate a French version of the WEL in a general and a clinical sample, and to explore the links between eating self-efficacy and psychosocial variables. In study 1, the general population sample included 432 adults (93% of women, mean age = 43.18 ± 11.93 years). In study 2, the clinical sample included 2010 adults with overweight and obesity (87% of women, mean age = 44.44 ± 11.25 years). Exploratory and confirmatory factor analyses were performed. Two distinct versions of the WEL were retained: a 12-item questionnaire intended for use in the general population, named WEL-Fr-G, and an 11-item questionnaire for clinical samples, named WEL-Fr-C. The two French versions of the WEL presented strong reliability and sensibility. In addition, study 2 provided support for the measurement invariance of the WEL-Fr-C across sex and Body Mass Index. The two versions are therefore psychometrically sound instruments for assessing eating self-efficacy in the general population (WEL-Fr-G) and clinical samples (WEL-Fr-C).

Beyond weight loss: current perspectives on the impact of calorie restriction on healthspan and lifespan

Introduction: Changes to mental, physical, and physiological functions drive the complex processes underlying the variable progression of human aging. Nutritional interventions are one of the most promising non-pharmacological therapeutics to attenuate aging in humans. This narrative review aims to describe the implications of moderate and prolonged calorie restriction (CR) in healthy adults without obesity that occur beyond weight loss.Areas covered: Findings from CR studies, such as the CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) trials, the most rigorous trials to date examining a prolonged 25% CR, are described. The main areas covered include; changes to anthropometrics, energy metabolism, cardiometabolic health, inflammation and immune function, physical fitness, health behaviors, and mental health in response to weight loss (1-year) and weight loss maintenance (2-year).Expert opinion: CR presents a novel and effective therapeutic approach for improving healthspan and biomarkers of lifespan. To date, scientific evidence suggests that continued CR, under medical supervision, is accompanied with persistent and beneficial effects on health outcomes independent of weight loss. Mechanisms are yet to be fully elucidated, and novel dietary approaches that may similarly attenuate aging-related conditions should be explored and compared to traditional CR.

Effects of caloric restriction on human physiological, psychological, and behavioral outcomes: highlights from CALERIE phase 2

Caloric restriction (CR) is a strategy that attenuates aging in multiple nonhuman species. The Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) trials are part of a research program aiming to test the effects of CR on aging and longevity biomarkers in humans. Building on CALERIE phase 1, CALERIE phase 2 (CALERIE 2) was the largest study to date to assess sustained CR in healthy humans without obesity. In a 24-month randomized controlled trial comprising 218 participants at baseline, CALERIE 2 showed that moderate CR, 11.9% on average, induced improvements in aging-related biomarkers without adversely affecting psychological or behavioral outcomes. The objectives of this report are to summarize and review the highlights of CALERIE 2 and report previously unpublished results on eating disorder symptoms and cognitive function. This article specifically summarizes the physiological, psychological, aging, behavioral, and safety results of the trial. Also provided are research directions beyond CALERIE 2 that highlight important opportunities to investigate the role of CR in aging, longevity, and health span in humans.

Calorie restriction for enhanced longevity: The role of novel dietary strategies in the present obesogenic environment

Calorie restriction (CR) is a potent modulator of longevity in multiple species. A growing body of evidence shows that sustained periods of CR without malnutrition improves risk factors involved in the pathophysiology of type 2 diabetes, cardiovascular diseases, cancer, and neurological disorders in humans. Innovative dietary strategies such as intermittent fasting and protein restriction have recently emerged as alternative approaches that improve markers of aging. Some of these newer strategies might provide benefits for healthy aging with little to no CR and therefore, compared to traditional CR, may be easier to follow. Further to providing an update of CR studies in humans, the present narrative review appraises the influence of these contemporary dietary strategies on mechanisms posited to drive CR-induced longevity in humans, including those involving energy metabolism, oxidative damage, inflammation, glucose homeostasis, and functional changes in the neuroendocrine systems. The review also discusses the utilization of these diets for populations in the current obesogenic environment, and comments on whether current research can inform an optimal diet that attenuates aging, can be easily followed, and promises to improve longevity in humans.

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.

Calorie Restriction and Aging in Humans

Calorie restriction (CR), the reduction of dietary intake below energy requirements while maintaining optimal nutrition, is the only known nutritional intervention with the potential to attenuate aging. Evidence from observational, preclinical, and clinical trials suggests the ability to increase life span by 1-5 years with an improvement in health span and quality of life. CR moderates intrinsic processes of aging through cellular and metabolic adaptations and reducing risk for the development of many cardiometabolic diseases. Yet, implementation of CR may require unique considerations for the elderly and other specific populations. The objectives of this review are to summarize the evidence for CR to modify primary and secondary aging; present caveats for implementation in special populations; describe newer, alternative approaches that have comparative effectiveness and fewer deleterious effects; and provide thoughts on the future of this important field of study.

Changes in body weight, adherence, and appetite during 2 years of calorie restriction: the CALERIE 2 randomized clinical trial

Background/Objectives:

The Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE) study showed that individuals who are non-obese were able to undergo significant calorie restriction (CR), yet the time course changes in adherence, weight, and appetite are unknown. This analysis aimed to investigate the time course changes in adherence, body weight, and appetite during the CALERIE study.

Subjects/Methods:

Overall, 143 participants (body mass index: 21.9–28.0 kg/m²) were randomized to a CR group that aimed to achieve 25% CR for 2 years. Throughout the intervention, body weight was measured, and appetite was assessed through visual analogue scales. Algorithms were utilized with body weight measurements to calculate adherence percentile score. Participants targeted an adherence percentile score of 50, though being between 80 (lowest acceptable adherence) and 10 (highest acceptable adherence) was adequate. Polynomial regression analyses were used to assess time course changes.

Results:

Polynomials indicated that adherence percentile score increased above 50 after approximately week 20, although adherence remained acceptable (adherence percentile score less than 80) (R² = 0.89; P < 0.001). Weight loss occurred until approximately week 60 and then plateaued (R² ≥ 0.92; P < 0.001). Hunger and thirst increased (R² ≥ 0.30; P < 0.001), but the total increase in scale scores were less than 10 mm throughout the intervention.

Conclusions:

In individuals who are non-obese, adherence to 25% CR declines after 20 weeks, but two years of CR that stimulates a meaningful reduction in weight, promotes aging-related benefits and negligibly affects appetite is viable.

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

Compared to low-fat diets, low-carbohydrate (CHO) diets cause weight loss (WL) over a faster time frame; however, it is unknown how changes in food cravings and eating behavior contribute to this more rapid WL in the early phases of dieting. We hypothesized that reductions in food cravings and improved eating behaviors would be evident even after a relatively short (4-week) duration of CHO-restriction, and that these changes would be associated with WL. Adult participants (n = 19, 53% males, mean ± SD: BMI = 34.1 ± 0.8 kg/m²; age 40.6 ± 1.9 years) consumed a CHO-restricted diet (14% CHO, 58% fat, 28% protein) for 4 weeks. Before and after the intervention, specific and total cravings were measured with the Food Craving Inventory (FCI) and eating behaviors assessed with the Three-Factor Eating questionnaire. Food cravings were significantly reduced at week 4, while women had significantly greater reductions in sweet cravings than men. Dietary restraint was significantly increased by 102%, while disinhibiton and hunger scores were reduced (17% and 22%, respectively, p < 0.05). Changes in cravings were unrelated to changes in body weight except for the change in high-fat cravings where those who lost the most weight experienced the least reductions in fat cravings (r = −0.458, p = 0.049). Changes in dietary restraint were inversely related to several FCI subscales. A short-term, low-CHO diet was effective in reducing food cravings. These data suggest that in subjects that have successfully lost weight on a low-CHO diet, those who craved high-fat foods at the onset were able to satisfy their cravings—potentially due to the high-fat nature of this restricted diet.