Optimal cognitive functions are necessary for activities of daily living and self-independence. Cognitive abilities are acquired during early childhood as part of progressive neurodevelopmental milestones; unfortunately, regressive changes can occur as part of physiological aging, or more ominously, pathological diseases, such as Alzheimer’s disease (AD). Cases of AD and its milder subset, mild cognitive impairment (MCI), are rising and would impose a burdensome impact beyond the individual level. Various dietary and nutritional approaches have potential for promising results in managing cognitive deterioration. Glucose is the core source of bioenergy in the body; however, glucose brain metabolism could be affected in aging cells or due to disease development. Ketone bodies are an efficient alternate fuel source that could compensate for the deficient glycolytic metabolism upon their supra-physiologic availability in the blood (ketosis), which, in turn, could promote cognitive benefits and tackle disease progression. In this review, we describe the potential of ketogenic approaches to produce cognitive benefits in healthy individuals, as well as those with MCI and AD. Neurophysiological changes of the cognitive brain in response to ketosis through neuroimaging modalities are also described in this review to provide insight into the ketogenic effect on the brain outside the framework of purely molecular explanations.

Interacting with nature may promote mental and physical health. There are multiple ways to interact with nature: indirectly, incidentally, and intentionally. How these types of interactions with nature may be associated with mental and physical health status and health behaviors is unclear. The purpose of this narrative review is to (1) describe the relationship between interactions with nature (indirect, incidental, and intentional) and mental and physical health outcomes and behaviors, (2) identify gaps in the literature, and (3) provide recommendations for future research. Considerable evidence suggests that interacting with nature, indirectly and intentionally, is associated with improvements in mental health and physical exhibitions of mental status. Furthermore, intentionally interacting with nature is associated with engagement in physical activity and gardening is associated with fruit and vegetable consumption. Research suggests that incidentally interacting with nature may be associated with positive mental health status. More research is needed to understand the relationships between incidental interactions with nature and physical health status and behaviors; as well as among all types of interactions with nature and physical health disorders, sleep, and dietary behaviors.

Objective: The activity of dopamine‐dependent retinal signaling can be assessed using electroretinography. Response of this system to oral food stimulation might provide accessible insight into the brain dopamine response to oral stimuli as retinal dopamine concentration is dependent upon mid brain dopamine concentration was postulated.Design and Methods: Nine individuals had cone ERG (b wave) response to oral food stimulation and oral methylphenidate (MPH) administration measured on separate days, and completed self reported eating behavior questionnaires.Results: Significant and similar increases in b wave response to both stimuli (P = 0.012 and P = 0.042, MPH and food, respectively) and significant correlations of the food stimulated b wave amplitude with binge eating related behavior as measured by the Gormally Binge Eating Scale (r = 0.68, P = 0.044) and self‐reported trait hunger as measured by the Stunkard and Messick Three Factor Eating Questionnaire (r = 0.67, P = 0.048) were found.Conclusion: The significant increase in food stimulated dopamine dependent b wave amplitude and correlation with methylphenidate stimulated b wave amplitude suggest that ERG may offer a relatively inexpensive and accessible methodology for potentially assess dopaminergic responses to food and other externally applied stimuli that have been implicated in the pathogenesis of a number of human diseases.

Chocolate elicits unique brain activity compared to other foods, activating similar brain regions and neurobiological substrates with potentially similar psychoactive effects as substances of abuse. We sought to determine the relationship between chocolate with varying combinations of its main constituents (sugar, cocoa, and fat) and its psychoactive effects. Participants consumed 5 g of a commercially available chocolate with increasing amounts of sugar (90% cocoa, 85% cocoa, 70% cocoa, and milk chocolates). After each chocolate sample, participants completed the Psychoactive Effects Questionnaire (PEQ). The PEQ consists of questions taken from the Morphine-Benzedrine Group (MBG), Morphine (M,) and Excitement (E) subscales of the Addiction Research Center Inventory. After all testing procedures, participants completed the Binge Eating Scale (BES) while left alone and allowed to eat as much as they wanted of each of the different chocolates. We found a measurable psychoactive dose–effect relationship with each incremental increase in the chocolate’s sugar content. The total number of positive responses and the number of positive responses on the E subscale began increasing after tasting the 90% cocoa chocolate, whereas the number of positive responses on the MBG and M subscales began increasing after tasting the 85% cocoa chocolate sample. We did not find a correlation between BES scores and the total amount of chocolate consumed or self-reported scores on the PEQ. These results suggest that each incremental increase in chocolate’s sugar content enhances its psychoactive effects. These results extend our understanding of chocolate’s appeal and unique ability to prompt an addictive-like eating response.

Interacting with nature, such as spending time in nature and having houseplants, has been associated with positive mental and physical health outcomes and behaviors but limited research has explored dietary behaviors. Therefore, this study examined the relationships among interactions with nature, diet quality, and sustainable dietary patterns. In this explanatory sequential mixed methods study, participants self-reported the frequency and duration of their interactions with nature and completed Diet History Questionnaire II, where Healthy Eating Index-2020 (diet quality) and EAT-Lancet Index (sustainable dietary pattern) scores were calculated. A purposive sample of participants completed an interview. Multiple regression models were used to analyze quantitative data. Qualitative data were thematically analyzed. The data were integrated by connecting and merging. Three hundred adults completed the survey and 30 were interviewed. Positive significant relationships among interactions with nature, diet quality (p < .001), and sustainable dietary patterns (p < .001) were found. Four themes highlighted how interacting with nature may affect dietary intake: engaging with the natural world relaxes the mind, paving the way for healthier eating habits; pursuing health draws us toward nature and positively influences dietary choices; a deep connection to nature sparks a desire to nourish the body with more fruits and vegetables; and thoughtfully participating in the food system promotes healthier choices for personal and planetary health. Integrated findings highlight that mental state moderates and connection to nature mediates the relationships of interest. These results may be used to promote dietary behaviors for personal and planetary health through nature-based interventions.