Overview

The purpose of this study is to see how adding avocado to a breakfast meal affects blood sugar control and signals of hunger and fullness after eating.

The investigators will test the effects of 3 breakfast meals on blood sugar control and signals of hunger and fullness after eating:

1. Whole-wheat bread and strawberry jam
2. Whole-wheat bread, strawberry jam, and avocado
3. Whole-wheat bread and strawberry jam (meal enriched with fat and fiber to mimic that of an avocado)

Participants will undergo 3 test periods, each separated by a week. Each test period consists of one day with set meals that the investigators will provide (breakfast, lunch, and dinner), and then the next morning, participants will eat a breakfast meal and have blood drawn several times over 4 hours.

Eligibility

Inclusion Criteria:

• Biological sex males or females
• Age 21 to 65 years
• BMI between 18.5 and 34.9 kg/m2

Exclusion Criteria:

• Actively pregnant or lactating women
• Diagnosis of prediabetes or diabetes (fasting glucose >100 mg/dL)
• Current diagnosis of uncontrolled hypertension (systolic BP: >160 mmHg, diastolic BP: >95 mmHg), may receive treatment for hypertension as long as on a stable regimen for the previous one month
• Current diagnosis of uncontrolled hyperlipidemia (fasting total blood cholesterol >200 mg/dL, fasting triglycerides >200 mg/dL), may receive treatment for hyperlipidemia as long as on a stable regimen for the previous one month
• Presence of kidney disease, liver disease, hyperthyroidism, untreated or unstable hypothyroidism, certain cancers, gastrointestinal disease, pancreatic disease, other chronic metabolic diseases or malabsorption syndromes, HIV, or inflammatory conditions (such as arthritis, asthma, Crohn's disease, inflammatory bowel disease, gout, Lupus)
• History of bariatric or certain other surgeries related to weight control
• Any medication used to lower blood glucose/antidiabetic medications [including, but not limited to metformin, sulfonylureas, glucagon-like peptide-1 (GLP-1) analogues, sodium-glucose cotransporter-2 (SGL2) inhibitors, thiazolidinediones, dipeptidyl peptidase (DPP)-IV inhibitors] as well as medications affecting weight, appetite/hunger or gut motility.
• Smoking or use of other tobacco products (during 6 months prior to the start of the study)
• Antibiotic use during the intervention or for 3 weeks prior to any treatment period
• History of eating disorders or other significant food preferences that would interfere with the diet intervention (e.g., vegan lifestyle, very low-fat diets, high-protein diets)
• Allergies or adverse reactions to study foods (e.g., gluten intolerance), or food aversions that would interfere with diet adherence
• Body weight loss of >10% within the last 6 months prior to study start
• Unable or unwilling to give informed consent or communicate with study staff
• Self-report of alcohol or substance abuse within the past 12 months and/or current acute treatment or rehabilitation program for these problems (long-term participation in Alcoholics Anonymous is not an exclusion)
• Other medical, psychiatric, or behavioral factors that in the judgment of the Principal Investigator may interfere with study participation or the ability to follow the intervention protocol
• Undergoing hormonal therapy of any kind, with the exception of a stable regime for the prior 6 months to study start.