Spud study: could potatoes help you sleep better?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Self-reported healthy adults * Aged 40-80 years old * Intake of ≤4 portions of fruits and vegetables (excluding potatoes) per day * Low sleep quality index of \>5 (Pittsburgh sleep quality index). Exclusion Criteria: * Shift workers and those with multiple jobs or carers who are required to wake through the night * Unwilling to refrain from dietary supplements * Unwilling to follow protocol and/or give informed consent * Diagnosed with Cardiovascular Disease (CVD), Type 2 Diabetes, Celiac disease, Insomnia, Sleep apnoea * Presence of gastrointestinal disorder * Users of drugs that are likely to alter gastrointestinal motility or nutrient absorption * History of substance abuse or alcoholism * Currently pregnant, planning pregnancy, breastfeeding, or having had a baby 12 months prior * Weight change of \>3kg in the preceding 2 months * BMI \<18.5kg/m2 or \> 35kg/m2, * Current smokers, or individuals who quit smoking in the last 6-months * Frequently consume wholemeal products (1-2 times per day, in the short screening FFQ) * Never consumed refined starchy staples, such as white pasta or rice (rarely or never, in the short screening FFQ) * High potato consumption (4-6 times per week, in the short screening FFQ) * High risk of obstructive sleep apnoea (answer yes to \>3 questions, in STOP-Bang questionnaire) * Vegetarian, Vegan, or pescatarian dietary preferences. * Diagnosed with mental health disorders, and/or on medicine for their mental health (antipsychotics, antidepressants, beta-blockers) * Chronic user of antihistamines * Fasting glucose \>7mmol/l (finger prick test at baseline clinic) * Is taking weight loss, or glucose regulating medications. * Has been unstable on blood pressure lowering medications for at least 3-months prior to enrollment.