The Effects of a 12-Month Weight Loss Intervention on Cognitive Outcomes in Adults with Overweight and Obesity

Effects of combined dietary intervention and physical-cognitive exercise on cognitive function and cardiometabolic health of postmenopausal women with obesity: a randomized controlled trial

BACKGROUND

Postmenopausal women with obesity are markedly at risk of cognitive impairment and several health issues. Emerging evidence demonstrated that both diet and exercise, particularly physical-cognitive exercise are involved in cognitive and health benefits. However, the comparative effect of diet, exercise, and combined interventions in postmenopausal women with obesity on cognition and cardiometabolic health is still lacking. Identifying the effective health promotion program and understanding changes in cardiometabolic health linking these interventions to cognition would have important medical implications. This RCT aimed to examine the effect of single and combined interventions of diet and exercise on cognitive function and cardiometabolic health in postmenopausal women with obesity.

METHODS

Ninety-two postmenopausal women with obesity were randomly assigned to diet group (intermittent fasting 2 days/week, 3 months), exercise group (physical-cognitive exercise 3 days/week, 3 months), combined group, or control group (n = 23/group). All cognitive outcomes and cardiometabolic outcomes were measured at baseline and post-3 months. Primary outcomes were executive functions, memory, and plasma BDNF levels. Secondary outcomes were global cognition, attention, language domain, plasma adiponectin levels, IL-6 levels, metabolic parameters, and physical function.

RESULTS

At the end of the 3-month intervention, the exercise and combined group demonstrated significant memory improvement which was accompanied by significant improvements in plasma BDNF level, insulin levels, HOMA-IR, %body fat, and muscle strength when compared to controls (p < 0.05). Only the combined intervention group demonstrated a significant improvement in executive function and increased plasma adiponectin levels when compared to control (p < 0.05). Surprisingly, no cognitive improvement was observed in the diet group (p > 0.05). Significant reduction in cholesterol levels was shown in the diet and combined groups when compared to controls (p < 0.05). Among the three intervention groups, there were no significant differences in all cognitive outcomes and cardiometabolic outcomes (p > 0.05). However, all three intervention groups showed significant improvements in plasma BDNF levels, weight, BMI, WHR, fat mass, and predicted VO2 max, when compared to control (p < 0.05).

CONCLUSION

These findings suggest that combined physical-cognitive exercise and dietary intervention are promising interventions to improve cognition and obesity-related complications of postmenopausal women with obesity.

TRIAL REGISTRATION

NCT04768725 ( https://clinicaltrials.gov ) 24th February 2021.

Acute high-intensity interval exercise improves food-related cognition in young adults with obesity: An ERP study

Purpose Cognitive function, particularly food-related cognition, is critical for maintaining a healthy weight and preventing the acceleration of obesity. High-Intensity Interval Exercise (HIIE) is an increasingly popular form of exercise and has been shown to improve physical fitness and cognitive function. However, there is limited research on the effects and underlying mechanisms of HIIE on general and food-related cognition among adults with obesity. The aim of the current study was to examine the influence of a single bout of HIIE on food-related cognition among young adults with obesity. Methods Fifteen young men with obesity (BMI = 33.88 ± 4.22, age = 24.60 ± 5.29 years) were recruited. Participants took part in a HIIE condition consisting of 30 minutes of stationary cycle exercise (5-min warm-up, 20-min HIIE and 5-min cool down), and a control session consisting of a time and attention-matched period of sedentary rest in a counterbalanced order. Behavioral (reaction time and accuracy) and event-related potential measures (P3 and the late positive potential, LPP) elicited during a food-related Flanker task were measured after the HIIE and control session. Results Shorter response times were observed following HIIE, regardless of congruency or picture type, with no change in accuracy. Increased P3 and LPP amplitudes were observed following HIIE relative to the control session. Conclusion The findings suggest a single bout of HIIE has a beneficial effect on general and food-related cognition among young adults with obesity, with increased recruitment of cognitive resources to support cognitive control. Future research is warranted to examine the dose-response relationship between acute bouts or longer participation in HIIE on food-related cognition in obesity.

Differentiating the influence of sedentary behavior and physical activity on brain health in late adulthood

Public health messaging calls for individuals to be more physically active and less sedentary, yet these lifestyle behaviors have been historically studied independently. Both physical activity (PA) and sedentary behavior (SB) are linked through time-use in a 24-hour day and are related to health outcomes, such as neurocognition. While the benefits of PA on brain health in late adulthood have been well-documented, the influence of SB remains to be understood. The purpose of this paper was to critically review the evolving work on SB and brain health in late adulthood and emphasize key areas of consideration to inform potential research. Overall, the existing literature studying the impact of SB on the components and mechanisms of brain health are mixed and inconclusive, provided largely by cross-sectional and observational work employing a variety of measurement techniques of SB and brain health outcomes. Further, many studies did not conceptually or statistically account for the role of PA in the proposed relationships. Therefore, our understanding of the way in which SB may influence neurocognition in late adulthood is limited. Future efforts should include more prospective longitudinal and randomized clinical trials with intentional methodological approaches to better understand the relationships between SB and the brain in late adulthood, and how these potential links are differentiated from PA.

The role of IGF-1 in exercise to improve obesity-related cognitive dysfunction

Obesity is an important factor that threatens human health. The occurrence of many chronic diseases is related to obesity, and cognitive function decline often occurs with the onset of obesity. With the further prevalence of obesity, it is bound to lead to a wider range of cognitive dysfunction (ORCD). Therefore, it is crucial to suppress ORCD through intervention. In this regard, exercise has been shown to be effective in preventing obesity and improving cognitive function as a non-drug treatment. There is sufficient evidence that exercise has a regulatory effect on a growth factor closely related to cognitive function-insulin-like growth factor 1 (IGF-1). IGF-1 may be an important mediator in improving ORCD through exercise. This article reviews the effects of obesity and IGF-1 on cognitive function and the regulation of exercise on IGF-1. It analyzes the mechanism by which exercise can improve ORCD by regulating IGF-1. Overall, this review provides evidence from relevant animal studies and human studies, showing that exercise plays a role in improving ORCD. It emphasizes the importance of IGF-1, which helps to understand the health effects of exercise and promotes research on the treatment of ORCD.

The Role of Intermittent Fasting and Dieting on Cognition in Adult Population: A Systematic Review of the Randomized Controlled Trials

OBJECTIVE

A healthy diet is a modifiable risk factor that may impact cognition. A unique type of diet may include intermittent fasting (IF), an eating pattern in which individuals go extended periods with little or no meal intake, intervening with periods of normal food intake. IF has multiple health benefits including maintenance of blood glucose levels, reduction of insulin levels, depletion or reduction of glycogen stores, mobilization of fatty acids, and generation of ketones. IF has shown neuroprotective effects as it may lead to increased neurogenesis in the hippocampus, which may contribute to cognitive resilience. Diets including IF were examined as lifestyle modifications in the prevention and management of cognitive decline.

METHODS

A systematic literature search was conducted for randomized controlled trials (RCTs) which assessed the effect of dieting on cognitive functions in adults.

RESULTS

Dietary Approaches to Stop Hypertension (DASH), low-glycemic diets, and caloric restriction have shown improvement in cognitive function; however, there was a negative impact on problem-solving in those with comorbid cardiovascular disease. There is also contradictory evidence that caloric restriction and diet alone may not be sufficient for the improvement of cognitive functions and that exercise may have better efficacy on cognition.

CONCLUSION

IF is considered a safe intervention, and no adverse effects were found in the reviewed studies; however, evidence is limited as there were only 9 low-quality RCTs that assessed the impact of IF on cognition. DASH, low-glycemic diets, and exercise may have effective roles in the management and prevention of cognitive decline, although further research is needed.

Impact of Diet and Exercise Interventions on Cognition and Brain Health in Older Adults: A Narrative Review

The ability to preserve cognitive function and protect brain structure from the effects of the aging process and neurodegenerative disease is the goal of non-pharmacologic, lifestyle interventions focused on brain health. This review examines, in turn, current diet and exercise intervention trends and the collective progress made toward understanding their impact on cognition and brain health. The diets covered in this review include the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), ketogenic diet, intermittent fasting, and weight loss management. The exercise approaches covered in this review include endurance, resistance, combined exercise programs, yoga, tai chi, and high-intensity interval training. Although valuable evidence is building concerning how diet and exercise influence cognitive performance and brain structure, many of the open questions in the field are concerned with why we see these effects. Therefore, more strategically designed intervention studies are needed to reveal the likely multiple mechanisms of action in humans.

Pre-post intervention exploring cognitive function and relationships with weight loss, intervention adherence and dropout

Objective

To evaluate the association between baseline cognitive function, intervention dropout, adherence and 3-month weight loss (WL) when controlling for confounding demographic variables.

Methods

107 (Mage = 40.9 yrs.), BMI in the overweight and obese range (BMI = 35.6 kg/m²), men (N = 17) and women (N = 90) completed a 3-month WL intervention. Participants attended weekly behavioral sessions, comply with a reduced calorie diet, and complete 100 min of physical activity (PA)/wk. Cognitive function tasks at baseline included Flanker (attention), Stroop (executive control) and working memory, demographics, body weight and cardiovascular fitness were assessed at baseline. Session attendance, adherence to PA and diet were recorded weekly.

Results

Baseline attention was positively correlated with age (p < .05), education (p < .05), attendance (p < .05), diet (p < .05) and PA (p < .05). Baseline executive control (p < .05) and working memory (p < .05) were each associated with % WL. Baseline executive control (p < .01) and working memory (p < .001) were also each associated with education. ANOVA indicated that baseline attention (p < .01) was associated with WL, specifically for comparing those who achieved 5-10% WL (p < .01) and those who achieved greater than 10% WL (p < .01) to those who dropped.

Significance

Results suggest that stronger baseline attention is associated with completion of a 3-mo. WL intervention. Executive control and working memory are associated with amount of WL achieved.

NCT registration

US NIH Clinical Trials, NCT01664715.

Reduced brain activity during a working memory task in middle-aged apolipoprotein E ε4 carriers with overweight/obesity

Objective

The apolipoprotein E ε4 (APOE ε4) allele and midlife obesity are independent risk factors for Alzheimer's disease (AD). Both of these risk factors are also associated with differences in brain activation, as measured by blood oxygenation level-dependent (BOLD) responses, in the absence of detectable cognitive deficits. Although the presence of these risk factors may influence brain activity during working memory tasks, no study to date has examined whether the presence of the ε4 allele explains variation in working memory brain activity while matching for levels of overweight/obesity. The primary aim of this study was to determine whether the presence of the ε4 allele is associated with differences in task-functional magnetic resonance imaging (fMRI) brain activation in adults with overweight/obesity. We predicted that ε4 carriers would have greater brain activation in regions that support working memory.

Methods

This ancillary study included 48 (n = 24 APOE ε4 carriers; n = 24 APOE ε4 non-carriers), sedentary middle-aged adults (Mean age = 44.63 ± 8.36 years) with overweight/obesity (Mean BMI = 32.43 ± 4.12 kg/m²) who were matched on demographic characteristics. Participants were a subsample enrolled in 12-month randomized clinical trial examining the impact of energy-restricted diet and exercise on cardiovascular health outcomes. Participants completed a n-back working memory task with fMRI, which were completed within one month of the start of the intervention. Participants also underwent pseudo-continuous arterial spin labeling scans, a MRI measure of cerebral blood flow (CBF).

Results

Compared to non-ε4 carriers with overweight/obesity, ε4 carriers with overweight/obesity had lower fMRI brain activity in the middle frontal gyrus, pre and post central gyrus, supramarginal gyrus, superior temporal gyrus, lateral occipital cortex, and angular gyrus (z range = 2.52-3.56) during the n-back working memory task. Differences persisted even when controlling for CBF in these brain regions.

Conclusion

These results indicate that presence of the APOE ε4 allele in middle-aged adults with overweight/obesity is related to altered brain activity during a working memory paradigm, which may confer risk for accelerated neurocognitive decline in late adulthood. Future research is needed to clarify the clinical implications of these findings in the context of risk for AD.

Effect of Mediterranean diet and Mediterranean diet plus calorie restriction on cognition, lifestyle, and cardiometabolic health: A randomized clinical trial

A Mediterranean diet and intentional weight loss each positively affect cognitive functioning. Combining both could produce synergistic effects on cognition. The purpose of this study is to compare a Mediterranean diet lifestyle intervention with and without caloric restriction versus control on cognition, lifestyle, and cardiometabolic disease. In a three-arm trial conducted between 2017 and 2020 in Chicago, one hundred and eight-five, 55–85-year-old, predominately non-Hispanic black females with obesity were randomized (2:2:1) to an 8-month Mediterranean diet plus caloric restriction intervention, Mediterranean diet alone, or control. The primary outcome was change from baseline to post-intervention in cognitive composite scores: attention, information & processing; executive function; and learning, memory, & recognition. Secondary outcomes were weight, lifestyle and cardiometabolic markers. The 8-month Mediterranean diet interventions did not significantly affect cognition. Adherence to a Mediterranean diet improved more in the Mediterranean diet plus caloric restriction arm (mean [SE] score change, +6.3 [0.7] points) and Mediterranean diet alone arm (+4.8 [0.7] points) relative to controls (+0.6 [0.9] points). Mean weight loss was greater among the Mediterranean diet plus caloric restriction arm (−4.6 [0.6] kg) compared to the Mediterranean diet alone (−2.6 [0.6] kg) and control arms (−0.6 [0.7] kg). The interventions did not affect activity or cardiometabolic risk markers; although, fasting insulin did decline in the Mediterranean diet plus caloric restriction arm relative to the Mediterranean diet alone and control arms. A Mediterranean diet lifestyle intervention with and without caloric restriction did not significantly affect cognitive function compared to controls. The Mediterranean diet interventions, however, significantly affected diet quality and body weight.

The relationship between fat mass and obesity associated gene polymorphism rs9939609 and resting cerebral blood flow in a midlife sample with overweight and obesity

Background

The single nucleotide polymorphism (SNP) rs9939609 in the fat mass and obesity associated fat mass and obesity associated gene (FTO) gene has been linked with increased BMI in adults. Higher BMI has been associated with poor brain health and may exert deleterious effects on neurocognitive health through cerebral hypoperfusion. However, it is unclear if there is a relationship between the FTO genotype and cerebral perfusion, or whether FTO genotype moderates the effects of weight loss on cerebral perfusion. Using data from a randomized controlled behavioral weight loss trial in adults with overweight and obesity, we tested (1) whether carriers of the A allele for FTO rs9939609 demonstrate different patterns of resting cerebral blood flow (rCBF) compared to T carriers, and (2) whether the FTO genotype moderates the effects of weight loss on rCBF. We hypothesized that carriers of the A allele would exhibit lower resting CBF in frontal brain areas compared to T/T homozygotes at baseline, and that intervention-induced weight loss may partially remediate these differences.

Methods and results

One hundred and five adults (75.2% female, mean age 44.9 years) with overweight or obesity were included in the analyses. These participants represent a subsample of participants in a larger randomized controlled trial (NCT01500356). A resting pseudo-continuous arterial spin labeling (pCASL) scan was acquired to examine rCBF. Age, sex, and BMI were included as covariates. At baseline, A carriers had greater rCBF in a diffuse cluster extending into the brainstem, motor cortex, and occipital lobe, but lower perfusion in the temporal lobe. We found no evidence that FTO moderated the effect of the intervention group assignment on rCBF changes.

Conclusion

Overall, these results indicate that (a) individual variation in rCBF within a sample with overweight and obesity may be attributed to a common FTO variant, but (b) a weight loss intervention is effective at increasing rCBF, regardless of FTO genotype.

Effects of Acute High-Intensity Interval Exercise and High-Intensity Continuous Exercise on Inhibitory Function of Overweight and Obese Children

This study aimed to examine whether a single bout each of high-intensity interval exercise (HIIE) and high-intensity continuous exercise (HICE) could improve inhibitory functions of overweight and obese children, and which mode of exercise was more beneficial. Seventy-two overweight and obese children, with (26.02 ± 1.05 kg/m²), aged 10-14 years (11.56 ± 1.03 years), were randomly assigned to three groups. The HIIE group completed a 30-min treadmill exercise session (5-min warm up, 20-min HIIE, and 5-min cool-down). The HICE group performed 30 min of rope skipping, while the control (CON) group watched a designated cartoon on a tablet computer for the same duration. Reaction time and number of errors in the Stroop test were determined before and after the intervention. The difference between pre- and post-test reaction time scores was higher in the HIIE and HICE groups than in the CON group, while the pre- and post-test difference in the number of errors was similar between groups. Overall, it is likely that both acute HIIE and HICE were similarly efficient in facilitating cognitive and inhibitory functions of children with overweight and obesity conditions, supporting the benefits of acute high-intensity exercise probability for cognitive functions of children in general, as well as of the population with overweight and obesity conditions.

Cognitive Aging and the Promise of Physical Activity

Is the field of cognitive aging irretrievably concerned with decline and deficits, or is it shifting to emphasize the hope of preservation and enhancement of cognitive function in late life? A fragment of an answer comes from research attempting to understand the reasons for individual variability in the extent and rate of cognitive decline. This body of work has created a sense of optimism based on evidence that there are some health behaviors that amplify cognitive performance or mitigate the rate of age-related cognitive decline. In this context, we discuss the role of physical activity on neurocognitive function in late adulthood and summarize how it can be conceptualized as a constructive approach both for the maintenance of cognitive function and as a therapeutic for enhancing or optimizing cognitive function in late life. In this way, physical activity research can be used to shape perceptions of cognitive aging. Expected final online publication date for the Annual Review of Clinical Psychology, Volume 18 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Can specific nutrients, foods, or dietary patterns modulate cognitive function in (older) adults? Latest evidence from randomized controlled trials

PURPOSE OF REVIEW

Epidemiological findings and results of randomized clinical trials in the last two decades have identified diet as a modifiable risk factor for cognitive decline, a predementia stage that is increasing worldwide as population ages. The literature on this critical association is expanding, making this review relevant and timely.

RECENT FINDINGS

Data from 15 trials and several systematic reviews/meta-analyses indicate that, in healthy older adults, isolated nutrients or antioxidant-rich foods usually fail to improve cognition. However, studies targeting populations at risk of cognitive decline tend to have positive results. There is ample epidemiological evidence of cognitive benefit from plant-based dietary patterns (i.e., Mediterranean diet), but more clinical trials are needed. Long-term multicomponent trials, simultaneously targeting several risk factors in patients with early dementia stages, offer promising evidence. A long-term multinutrient intervention in patients at risk for dementia appears as a sound preventive strategy.

SUMMARY

This review summarizes the latest evidence on nutrients, foods, and dietary patterns as tools to improve cognition and promote brain health. Dietary changes are important to help delay cognitive decline, particularly in populations more at risk. Large-scale strategies based on healthy diets combined with other health-promoting lifestyle changes should be a public health priority.

Obesity-induced cognitive impairment in older adults: a microvascular perspective

Over two-thirds of individuals aged 65 and older are obese or overweight in the United States. Epidemiological data show an association between the degree of adiposity and cognitive dysfunction in the elderly. In this review, the pathophysiological roles of microvascular mechanisms, including impaired endothelial function and neurovascular coupling responses, microvascular rarefaction, and blood-brain barrier disruption in the genesis of cognitive impairment in geriatric obesity are considered. The potential contribution of adipose-derived factors and fundamental cellular and molecular mechanisms of senescence to exacerbated obesity-induced cerebromicrovascular impairment and cognitive decline in aging are discussed.

A Conceptual Model of Long-Term Weight Loss Maintenance: The Importance of Cognitive, Empirical and Computational Approaches

Living with obesity is related to numerous negative health outcomes, including various cancers, type II diabetes, and cardiovascular disease. Although much is known about the factors associated with obesity, and a range of weight loss interventions have been established, changing health-related behaviours to positively affect obesity outcomes has proven difficult. In this paper, we first draw together major factors that have emerged within the literature on weight loss to describe a new conceptual framework of long-term weight loss maintenance. Key to this framework is the suggestion that increased positive social support influences a reduction in psychosocial stress, and that this has the effect of promoting better executive functioning which in turn facilitates the development of healthy habits and the breaking of unhealthy habits, leading to improved ongoing maintenance of weight loss. We then outline how the use of computational approaches are an essential next step, to more rigorously test conceptual frameworks, such as the one we propose, and the benefits that a mixture of conceptual, empirical and computational approaches offer to the field of health psychology.