The proposed work will investigate the effect of almond consumption as a snack on human gastrointestinal microbiota and on metabolic health.

This study is a randomized, controlled, investigator-blinded, parallel arm design with two treatment conditions. There will be a phone screening, in person pre-intervention testing, a one-week baseline period devoid of all nuts and seeds followed by a 12-week intervention period, and a post-testing appointment. Participants will be randomized to consume almonds or isocaloric snack for 12 weeks. Participants will provide stool samples during baseline testing and during the 12th week of the intervention.

Inclusion Criteria:

• Males & Females
• 30-60 years of age
• BMI 25-34.9 kg/m^2
• Ability to drop off fecal sample within 15 minutes of defecation

Exclusion Criteria:

• Physician diagnosed metabolic or gastrointestinal diseases
• Fasting blood glucose >126 mg/dL
• Blood pressure >160/100 mm Hg
• Anemia
• Elevation in serum transaminases (i.e. >3 times the upper limit of normal)
• Evidence of liver disease, including primary biliary cirrhosis or gallbladder disease, constipation
• Currently taking lipid-lowering medications, oral hypoglycemic agents, or insulin, or medications known to impact bowel function.
• Pregnant, breastfeeding or postmenopausal
• Smoker, tobacco use
• Allergic to nuts
• Consume > 2 alcoholic beverages/day
• Abuse drugs
• Have had > 5% weight change in the past month or > 10% change in the past year
• Have taken antibiotics during the previous 2 months
• Unable to consume the experimental treatments (almonds or pretzels)
• Bariatric surgery
• Gallbladder removal
• Allergic to lidocaine or other topical anesthetics