Blueberry Enhances Activity and Cognition Through Increased Vascular Efficiency

Inclusion Criteria: * Age 60 and older * Overweight (BMI ≥25 to 35 kg/m2) * Well-controlled blood pressure (\< 150/90 mmHg) * Able to speak and understand spoken and written English * Cognitively normal (Mini-Cog score 3-5) * Able to walk independently * Social security number (required for compensation) * Own a smartphone or other mobile device capable of downloading the Garmin Connect app Exclusion Criteria: * Exercise \> 150 minutes/week * Unwillingness or inability to be randomized to any one of two intervention groups without knowing which (double-blind), submit to all study testing, or continuously participate in a randomly assigned diet and exercise intervention for six months. * Unwilling to restrict consumption of anthocyanin-rich foods * Unwillingness to abstain from mood altering drugs (including marijuana but excluding CBDs) for 7 days prior to baseline and endpoint testing. * Self-reported vegetarian or vegan. * Inability to complete written recording forms including journals of eating and exercise behaviors. * Inability to complete written and computerized cognitive tasks (presented in English). * Allergy or intolerance to blueberry or placebo powder ingredients Placebo ingredients include: maltodextrin, fructose, artificial blueberry flavor, natural blueberry flavor, artificial purple color (water, FD\&C Red #40, FD\&C Blue #1, malic acid, sodium benzoate) citric acid, and artificial red color (water, FD\&C Red #40, malic acid, sodium benzoate, silica dioxide). * Gastrointestinal disorders that influence digestion and absorption of food, e.g., IBD * History of frequent urinary tract or Clostridium difficile infections * Presence of unstable, acutely symptomatic, or life-limiting illness. * Regular use of medication that interferes with the measurement of study outcomes as determined by the study physician. * Unstable use of medications, other than statins, for conditions associated with metabolic syndrome (hypertension, diabetes, dyslipidemia) during the prior 6 months or during the study. * Antibiotic use in the last 3 months. * Cigarette smoking, chewing, or use of nicotine replacement products in the past 3 months or during the course of the study. * Colonoscopy in last 2 months. * History of stomach or bowel resection (other than appendectomy), gastric bypass or other bariatric weight loss procedure effecting absorption. * History of significant weight instability (defined as \> 10 pounds weight gain or loss over one month prior to study participation). * History of cancer treatment (other than melanoma skin cancer) and not "cancer-free" for at least 1 year. * History of anti-hormonal therapy (eg., for breast or prostate cancer) within the last 6 months.