A thorough characterization of glucose metabolism and "inflammaging" in elderly subjects will help determine to what extent each of these factors affects muscle mass/function and contributes to age-related muscle wasting. The investigators will correlate patterns of insulin secretion/sensitivity with "muscle "quality/quantity" in diabetic and non-diabetic elderlies (≥70 years old). By comparing different groups (healthy, sarcopenic, diabetic, diabetic/sarcopenic), the investigators expect to identify an "oxidative/inflammatory signature" (e.g., circulating interleukins/myokines, plasma antioxidant capacity) specific for the sarcopenic phenotype and related to muscle insulin resistance.

Inclusion Criteria:

• Type 2 diabetes mellitus: patients taking drugs for diabetes will be diagnosed as having diabetes. In all other patients, a diagnosis will be established according to the criteria of the American Diabetes Association
• Sarcopenia (non-severe): individuals with low muscle mass and either low muscle strength or low physical performance will be diagnosed with sarcopenia, according to the criteria of the European Working Group on Sarcopenia in Older People (EWGSOP)
• Healthy volunteers: no diabetes, no sarcopenia and none of the exclusion criteria

Exclusion Criteria (overall population):

• acute diseases,
• chronic obstructive pulmonary disease (COPD)
• conditions associated with sarcopenia/altered body composition (e.g. disability, altered endocrine function, chronic diseases, nutritional deficiencies, cancer),
• obesity (body mass index ≥30 kg/m2)
• moderate-severe hepatic disease,
• chronic kidney disease (estimated glomerular filtration rate <30 ml/min per 1.73m2),
• metal prostheses,
• recent or ongoing infection,
• inability or unwillingness to provide informed consent

Exclusion Criteria (diabetic population):

• type 1 diabetes,
• hemoglobin A1c >8.5% (69 mmol/mol),
• basal-bolus insulin therapy,
• insulin pump therapy,
• proliferative diabetic retinopathy,
• diabetic foot.

Elderly (≥ 70 years) subjects