Investigating the effect of optimising amino acid intake on obesity rates in individuals aged 65-80 years.

INTERVENTION: Participants will be provided with ad libitum access to a standard diet containing 18‐19% of energy as protein, 30‐35% fat and up to 45‐65% carbohydrate as per the Acceptable Macronutrient Distribution Ranges set by the NHMRC. A bottle of 1L of olive oil will be provided to participants to be used as salad dressing. Study diets will be provided via a meal delivery company (Kinela). Milk (up to 100mL a day), fresh fruit (up two serves of fruit a day) and vegetables (up to two cups of salad a day) will also be allowed as additions to the diet provided and a list of approved additions and quantities will be provided. Those randomised to BCAA, BCAA+tryptophan and BCAA+methionine will be provided with supplements to be consumed in conjunction with their meals. All foods and supplements consumed will be recorded in the study food diary to be kept by each participant. Participants in the BCAA group will be provided with a sealed bottle containing 100 capsules of Solgar, BCAA Plus, Free Form Capsules which contains 540mg of L‐leucine, 360mg of L‐isoleucine and 300mg of L‐valine each. Participants will be asked to consume one capsule, three times daily of this supplement along with their food (i.e. breakfast, lunch and dinner) for 4 weeks. Participants in the BCAA + tryptophan group will be provided with a sealed bottle containing 60 capsules of Now Foods L‐Tryptophan, Double Strength which contains 1000 mg of L‐tryptophan each and a sealed bottle containing 100 capsules of Solgar, BCAA Plus, Free Form Capsules which contains 540mg of L‐leucine, 360mg of L‐isoleucine and 300mg of L‐valine each. Participants will be asked to consume one capsule, twice daily of the tryptophan supplement along with their main meals (i.e. lunch or dinner) and one capsule, three times d CONDITION: Diet and Nutrition ‐ Obesity Obesity; ; Obesity PRIMARY OUTCOME: Objective/quantitative appetite assessed by plasma FGF21 and grehlin.[Baseline and four‐week post intervention commencement.] Subjective/qualitative appetite assessed by participant self‐report (assessed by appetite questionnaire).[Baseline and four‐week post intervention commencement.] Subjective/qualitative energy intake assessed by participant self‐report (weighed food record)[Baseline and four‐week post intervention commencement.] INCLUSION CRITERIA: Females (post‐menopausal) or males, 65‐80 years, BMI 20‐35kg/m2 will be recruited SECONDARY OUTCOME: Waist and hip circumference will be measured using a measuring tape made of fiberglass.[Baseline and four‐week post intervention commencement.] Blood pressure: Three systolic and diastolic blood pressure measurement using a sphygmomanometer will be taken 1 minute apart after 5 minutes of quiet rest in a seated position.[Baseline and four‐week post intervention commencement.] Body composition: Body composition will be measured via the BodPod and the following measures will be obtained: body mass, body fat mass, body fat free mass.[Baseline and four‐week post intervention commencement.] Grip strength assessed using a hand dynamometer.[Baseline and four‐week follow‐up] Lower limb strength assessed using number of repeated chair stands in 30 seconds.[Baseline and four‐week post intervention commencement.] Peripheral blood mononuclear cells (PBMC) for cytokine analysis will be measured as a marker of inflammation. [Baseline and four‐week post intervention commencement.] Serum biochemistry including EUC, calcium, phosphate, protein, albumin, amino acids, triglycerides, total cholesterol, HDL cholesterol, glucose, insulin, CRP, IGF‐1, leptin and liver function (ALT, AST and LD) will be measured as markers of cardio‐metabolic health. [Baseline and four‐week post intervention commencement.] Short chain fatty acids will be measured in serum as marker of inflammation.[Baseline and four‐week post intervention commencement.] Six‐meter walk speed will be measured to assess functional status and overall health. [Baseline and four‐week post intervention commencement.] Stool samples will be used for measurement of the gut microbiome. [Baseline and four‐week post intervention commencement.]