The investigators hypothesize that the improvements in insulin sensitivity, beta (β)-cell function, and inflammation will be greater, and the improvement in sarcopenic obesity will be less, in younger versus older individuals after substantial weight loss induced by sleeve gastrectomy bariatric surgery.

With an aging population that is increasingly susceptible to obesity and obesity-related comorbidities including sarcopenia and diabetes, effective and safe treatment options tailored to the needs of older adults are imperative. While medication and lifestyle interventions generally fail to achieve sustained large-scale weight loss, bariatric surgery is the most effective long-term weight loss treatment for obese patients and improves many of the medical complications associated with obesity. Sleeve gastrectomy (SG) results in substantial weight loss and may be more appropriate for older adults due to its low rate of complications and mortality. Therefore, SG has been proposed as a reasonable primary treatment modality in older obese individuals, with a substantial recent increase in the number of interventions performed. Despite the potential benefits, very little is known of the physiologic and metabolic effects of bariatric surgery, including SG, on glucose homeostasis and muscle physiology in older adults. A fundamental understanding of the effects of excess adiposity and weight loss interventions is of profound importance, especially with emerging evidence that earlier treatment of obesity may delay/prevent many comorbidities. An underlying inflammatory state has been implicated in the pathogenesis of sarcopenia and insulin resistance and may provide an important connection to the age-related declines seen in older obese patients. Therefore, this study aims to evaluate the modifying effect of age and inflammation on the SG-induced changes in body composition, muscle physiology, and insulin sensitivity. This protocol will be conducted in two age cohorts (greater than 60 and less than 50 years old).

Inclusion Criteria:

• Age 21-80 yrs old
• BMI ≥ 35 kg/m2
• Undergoing laparoscopic sleeve gastrectomy (SG)

Exclusion Criteria:

• Smokers
• Presence of diabetes mellitus
• Taking any medication that might affect metabolism
• Severe organ dysfunction
• Pregnant or breastfeeding
• Prior gastrointestinal surgery that might affect study results
• Unable or unwilling to follow the study protocol or any reason the research team believes the subject is not an appropriate candidate for this study
• Weight >450 pounds (Will be unable to fit on the DXA scanner)

Patients scheduled to undergo laparoscopic sleeve gastrectomy (SG) at The Ohio State University (OSU) Wexner Medical Center will be divided into two cohorts: 1). Greater than or equal to 60 years of age and 2). Less than 60 years of age.