This randomized, controlled, single-blinded study will compare how a ketogenic weight loss diet, supplemented with either animal- or plant-based protein affects: (i) metabolic markers (adipokine and cytokine) in adipose tissue and blood, (ii) adipose tissue immune cell profiles, and (iii) adipocyte characteristics and their interaction with other cells (e.g. immune cells and muscle cells). To better determine how tissue characteristics affect the whole body level, the relationships between adipose tissue characteristics and blood lipid and inflammatory markers will also be examined. Participants undergo anthropometric measurements, questionnaires, body composition assessment, energy assessment, blood draws, and adipose tissue biopsies from the abdominal and femoral adipose tissue depots