APPETITE: Plant Protein and Exercise Solutions for the Prevention of Undernutrition in Older Adults.

12-week change in physical activity score will be assessed using 7-day accelerometery data. This is a validated device that is installed onto an individuals thigh for continuous readings. The data generated describes the amount of time spent engaging in physical activities and sedentary activities, and gives an output score in MET.h (Metabolic EquivalenT hour). This is a measure of energy usage over and above what is required at rest, where 1MET is equivalent to oxygen uptake of 3.5ml/kg body weight/minute

12-week change in resting energy expenditure will be assessed using indirect calorimetry

12-week change in handgrip strength will be assessed using a Jamar hydraulic hand dynamometer

12-week changes in isometric leg strength will be assessed using a seated leg extension dynamometer

12-week change in cardiorespiratory fitness will be assessed using the 400-meter walk test

12-week change in physical function will be assessed using the Short Physical Activity Battery (SPPB)

12-week changes in perceived quality of life will be assessed using the EuroQol (European Quality Of Life) questionnaire (EQ-5D-5L). This consists of self-assessed rating of health under 5 dimensions (Mobility, Self-Care, Usual Activity, Pain/Discomfort, Anxiety/Depression), and perceived overall health on a magnitude scale (0-100) anchored with opposing statements (0= the worst health you can imagine; 100= the best health you can imagine).

12-week change in body composition will be assessed using air displacement plethysmography (Bodpod).

12-week change in dietary restraint will be assessed using the Cognitive Dietary Restraint (CDR) subscale of the Three Factor Eating Questionnaire (TFEQ). The questionnaire consists of a subscale of 6 questions relating to cognitive dietary restraint from the orignal 50 item questionnaire. The questions are a mix of 'true/false', and likert scale type answers.

12-week change in energy, protein and fibre intake assessed using a three-day non-weighed dietary record

12-week change in appetite-related gut hormone response to a fixed meal. Assessed in circulating peripheral bloods at fasting, and at regular intervals postprandially (minute 30, 60, 90, 120, 150, \& 180).

12-week change in gut microbiota quality and diversity assessed by faecal matter and faecal water.

12-week change in fasting peripheral blood profile (insulin, leptin, glucose, amino acid, fatty acid)

Body composition will be assessed by BIA across all sites at baseline and post intervention. BIA is a quick non-invasive method of measuring body composition. Bioelectrical impedance analysis (BIA) measures body composition based on the rate at which an electrical current travels through the body. Body fat (adipose tissue) causes greater resistance (impedance) than lean mass and slows the rate at which the current travels. The device provides an output of absolute (Kg) and percentage (% of total mass) of fat mass (FM) and fat-free mass (FFM).

The SNAQ questionnaire is used to assess an older adults usual appetite. The SNAQ is a self-administered questionnaires adapted from the Appetite, Hunger and Sensory Perception questionnaire (AHSP), an appetite assessment tool validated among community-dwelling older adults. It consists of 4 multiple choice statements, where an individual reads the beginning of the statement and is presented with 5 options that best describe their situation. Each question derives a score between 1 - 5 with lower scores indicating poorer appetite. The questionnaire scores between 4 - 20 with scores </= 14 indicating poor appetite.

Rating of the breakfast and lunch test meals by visual analogue scales (VAS). The VAS is a validated tool for assessing subjective sensory experience. On each 100-mm line, a question is asked relating to sensory aspects of the meal (E.g., How pleasant was the meal?). The subject will mark along the 100mm line where they feel their experience, in terms of the question, rests. On ether end of the 100mm line are opposing terms (E.g., "not at all", "extremely").

Body weight will be measure using a calibrated scales, shoes and heavy clothing removes, and recorded in kilograms.

Height will be measured in centimetres using a stadiometer. Participants will be measured barefoot and asked to take a full inhalation prior to stepping out from the device. Measurements are taken at the peak of the inhalation.

Calf circumference is measures using a non-stretch tape measure at the widest part of the calf muscle and recorded in centimetres.

Questionnaire specific to the project. This questionnaire will serve to provide feedback about participants experience while enrolled on the project. The questionnaire will include a series of Likert style questions and open-ended questions. The purpose is the provide feedback to the study team on what participants liked or disliked about the experience. This will serve to inform future management of studies.

DXA will be performed on a sub-sample of participants enrolled on the APPETITE study. A DXA can involves a large scanning arm being passed over the body to measure compartments of the body structure. As the scanning arm is moved slowly over your body, a narrow beam of low-dose X-rays will be passed through the part of your body being examined. DXA is a quick and non-invasive scan that provides in-depth analysis of the main components of your body; fat, muscle and bone.

by electromyography (EMG)

from muscle biopsy

This refers to the analyses of muscle biopsies. Biopsies will be taken using MEDAX/BF14100-C0; Bio-Feather with coaxial 14 g 10 cm. The following parameters will then be measured in the sample using western blot with specific antibodies for total proteins or by their activated phosphorylated form: 1) markers of denervation (AChR ; agrin/MuSK/Lrp4, NCAM, Myog); 2) markers of protein turnover (atrogin1, MURF1, LC3, BNIP3, Akt-dependent mTOR and FoxO); 3) markers of mitochondrial dynamics (OPA1, DRP1) and; 4) markers of energy metabolism pathways (AMPK and PGC1alpha).

Trained immunity describes the long-term functional reprogramming of innate immune cells after exposure to a primary insult which leads to an augmented response upon stimulation with the same ligand after returning to a non-activated state. Will habitual ingestion of plant protein combined with PA results in increased ability of macrophages to undertake innate immune train in adults over the age of 65. Effects will be quantified by comparing the presence of TNF alpha in human monocytes at baseline and following a 12-week intervention.