The goal of this observational study is to learn about changes in oral processing and appetite in older adults aged 65+ years old. The main question it aims to answer is if oral processing affects gastric emptying in older adults (≥65 years old).

• To investigate if food intake and satiety differ between faster and slower eaters, within older adults (≥65 years old).
• To assess if chewing rate, salivary flow rate, oral processing and gastric emptying differ between older adults (≥65 years old) with smaller versus bigger appetites.

Inclusion Criteria:

• 65 years old or over (no upper age limit);each group will contain an equal number of male and female participants;
• living sufficiently local to attend the two visits needed;
• able to understand and communicate in English language.

Exclusion Criteria:

• Diagnosed dysphagia;
• (recent) oral surgery that significantly affects eating and/or swallowing;
• diagnosis of type 1 or type 2 diabetes;
• participant undergoing current treatment for cancer;
• participants with zero natural teeth;
• severe loss of appetite and not able to finish a meal (based on CNAQ) and/or people on special or therapeutic diets that restrict the consumption of a full meal and/or the meals provided;
• not able to provide informed consent as defined by the T-CogS test (participants with T-CogS < 22 will be excluded);
• participants having a pacemaker;
• not able to accept the two meal dishes provided and/or relevant food/ingredient included in the meals allergies or intolerances or aversions;
• not able to feed themselves.

Healthy adults aged 65 years old or older

No personal identification data will be shared. The study is not under an obligation to share data, however, it is possible that some of the individual (unlinked / non-identifiable) data will be useful in a meta-analysis and, hence sharing individual participant data (IPD) will be considered.