Acute and Chronic Effects of Obesity

Inclusion Criteria: We are recruiting two groups of sedentary or untrained males and pre-menopausal females (age 25-40 years) with body mass indices (BMI) between 30.0-39.9 kg/m\^2. All participants will be required to provide a medical record and/or photographic evidence of weight at childhood (around age of 10-17 years old). Individuals with BMI between 40.0-41.9 may be included in the case that an individual with a much shorter height falls within this range, as BMI does not always properly define obesity type. Once the participant completes their DEXA scan, we will be able to more accurately assess the participant's obesity level and re-evaluate their elgibility. Exclusion criteria: Participants will be excluded if they are pregnant or planning to become pregnant, breast-feeding, presently using nicotine containing products (e.g. cigarettes, chewing tobacco, nicotine gum etc.), taking certain anti-depressants and anti-hypertensives. More modern medications will not need to be excluded as they don't affect weight loss or weight gain. As medication use will be screened, if the participant is using medications that do not affect our outcomes they will be included in the study. Participants will also be excluded if they have had any surgery (e.g. gastric bypass, magnetic implants) or have any conditions (e.g. iron deficiency anemia) or diseases (e.g. diabetes, cancer, IBD, history of eating disorders or mental illness) that may affect immune function and thus study outcomes, or the ability to participate in the study. Participants must also have been weight stable for at least 2 months.