Table 1.
Trial eligibility criteria
| Inclusion criteria | |
| • Men or women ages 40 to 70 years | |
| • Any race or ethnicity | |
| • HbA1c 6.0–6.9% | |
| • Willing and able to provide informed consent | |
| Exclusion criteria | |
| • Diagnosed type 1 diabetes mellitus based on patient self-report | |
| • Use of agents affecting glycemic control (medications for diabetes, oral glucocorticoids) within the past 3 months prior to enrolment based on patient self-report | |
| • Medical condition in which low-carbohydrate diet may not be advised (estimated glomerular filtration rate (eGFR) ≤ 45 mL/min/1.73 m2, which is close to the 5th percentile of eGFR among non-diseased individuals of 70 years of age [36], self-report of liver disease due to hepatitis or alcohol; osteoporosis; untreated thyroid disease; gout; or cancer (other than non-melanoma skin cancer) requiring treatment in the past year, unless prognosis is excellent) | |
| • Factors that may affect HbA1c: hemoglobin < 11 mg/dL (cutpoint for moderate-to-severe anemia, which could lead to falsely elevated or lowered HbA1c) [37], recent blood donation or blood transfusion (self-report, past 4 months), human immunodeficiency virus (self-report) [38] | |
| • Self-reported history of intensive care unit stay due to coronavirus disease 2019 (COVID-19) in the past 3 months, as severe COVID-19 may affect blood glucose levels | |
| • Allergies to nuts | |
| • For women, current pregnancy, breastfeeding, or plans to become pregnant during the study | |
| • Consumption of ≥ 21 alcoholic drinks per week or consumption of ≥ 6 drinks per occasion | |
| • For continuous glucose monitor (CGM) collection at the end of the study period only: known allergy to adhesives or other products involved with CGM use (e.g., skin disinfectants), current pregnancy, currently on hemodialysis or peritoneal dialysis, or people with other implanted medical devices (e.g., a pacemaker) | |
| • Current or planned residence making it difficult to meet trial requirements (due to distance from study site and/or challenges regularly traveling to site) | |
| • Current participation in lifestyle or pharmaceutical trial | |
| • Participation of another household member in the study; employees or persons living with employees of the study | |
| • Other concerns regarding ability to meet trial requirements, at the discretion of the principal investigator or study coordinator |