Accumulating evidence indicates obesity is associated with reduced cognitive functioning, particularly attention and executive function, as well as maladaptive eating behaviour such as uncontrolled eating. The current study examined relationships between eating patterns and attention/executive function test performance in lean and obese individuals. Sixty-two (32 lean, 30 obese) healthy young adults (21.13 ± 2.31 years; 56.5% female) completed the abbreviated Three-Factor Eating Questionnaire (TFEQ-R18) to assess eating patterns, including uncontrolled eating, cognitive restraint, and emotional eating. The Go/No-Go (GNG), Running Memory Continuous Performance Test (RCMPT) and Standard Continuous Performance Test from the Automated Neuropsychological Assessment Metrics-4 were administered as measures of executive functioning and attention. An independent samples t-test revealed greater report of uncontrolled eating in obese compared with lean participants (t[60] = -2.174, P < 0.05; d = -0.55) but no differences in cognitive restraint or emotional eating. Multivariate analysis of variance revealed cognitive differences between lean and obese groups (F[6, 54] = 3.86, P < 0.005; λ = 0.70; ηp(2) = 0.30), which were driven by GNG reaction time (F[1, 59] = 8.36, P < 0.01, d = 0.74). Pearson bivariate correlations revealed a positive correlation between uncontrolled eating and reaction time on GNG (r = 0.343, P < 0.05) and RMCPT (r = 0.267, P < 0.05) in all participants. Relative to lean participants, obese individuals reported higher levels of uncontrolled eating and exhibited slower performance on a task of inhibitory control. In the full sample, greater self-reported dyscontrol in eating behaviour was related to slower inhibitory control and working memory. Results support a link between executive function and control of eating behaviour. Obese individuals may be more vulnerable to difficulties in these domains relative to those who are lean.

Convergent evidence demonstrates that greater physical activity is associated with better cognitive functioning across many patient and healthy samples. However, this relationship has not been well examined among obese individuals and remains unclear. The present study examined the relationship between performance-based measures of attention/executive function and self-reported physical activity, as measured by the International Physical Activity Questionnaire, among lean (n = 36) and obese (n = 36) college students. Lean individuals performed better than obese individuals on measures of attention/executive function. No significant differences in self-reported physical activity emerged between weight groups. Higher self-reported physical activity was related to faster reaction time in lean individuals but slower reaction time in obese individuals. Additionally, in lean individuals, higher levels of self-reported physical activity were related to more errors on a task of speeded inhibitory control. The results are consistent with previous research demonstrating that greater physical activity is associated with faster attention and executive function abilities in healthy samples and highlight the importance of examining reaction time and accuracy indices separately on these measures. The lack of association among obese individuals may be due in part to inaccurate self-report in the current study. Additionally, the cognitive consequences of obesity may outweigh the benefits of physical activity in this group. Future work should investigate these associations in obese individuals using physical activity interventions, as well as a combination of self-report and objective measures to investigate discrepancies in reporting.

Young adults who were obese but otherwise healthy had higher fasting glucose levels compared with normal weight peers. Higher glucose levels were associated with poorer cognitive performance on tests of inhibitory control, especially among individuals with prediabetes levels. Thus, subclinical elevations in blood glucose may contribute to cognitive impairment and, ultimately, greater impulsivity-well in advance of the development of chronic disease states (e.g., insulin resistance or Type 2 diabetes) and independently of excess adiposity--though prospective studies are needed to determine directionality of this relationship.

Background: Serum insulin-like growth factor-1 (IGF-1) is a mitogenic peptide involved in the regulation of cell proliferation, differentiation, and apoptosis in a wide variety of cells and tissues. Recent research suggests higher circulating levels of IGF-1 are associated with better cognitive performance in healthy older adults and in early stages of Alzheimer's disease, although the cognitive profile associated with elevated IGF-1 has not been examined in persons with mild cognitive impairment. Methods: Thirty-one participants (age: 83.71 1 3.59 years; 58% women) with mild cognitive impairment completed neuropsychological testing and 12-hour fasting blood draw to assess serum IGF-1. Results: Partial correlations between serum IGF-1 and neuropsychological measures were conducted, adjusting for insulin, body mass index, and age. Higher IGF-1-values were associated with better global cognition (Modified Mini Mental State Exam: r = 0.39, P = 0.04) and verbal list learning (Hopkins Verbal Learning Test learning: r = 0.38, P = 0.05), Hopkins Verbal Learning Test free recall (r = 0.41, P = 0.03), and Hopkins Verbal Learning Test recognition discriminability (r = 0.46, P = 0.01). A similar trend emerged for executive function as tested by the Frontal Assessment Battery (r = 0.33, P = 0.09). Conclusion: Results suggest higher levels of serum IGF-1 are associated with better cognitive performance in persons with mild cognitive impairment, particularly on tests of learning and memory. These findings suggest IGF-1 may be neuroprotective not only in healthy older adults, but also in adults in the earliest stages of Alzheimer's disease. Further investigation is needed to clarify the nature of this relationship, particularly prospective studies.

Results suggest that greater dairy intake was associated with poorer memory performance in older adults with HF. Several possible explanations for these findings exist, including the contribution of high-fat dairy to underlying physiological processes that promote vascular cognitive impairment. Prospective studies employing objective measures specific to high and low fat dairy are needed to clarify this possibility.