MetabolismGrowth Hormone (HGH)A hormone that supports fat metabolism and helps preserve lean tissue. Its secretion rises during fasting, though the rise is transient and its muscle-building effect is limited, because IGF-1 falls at the same time. Related Terms IGF-1 (Insulin-like Growth Factor 1)CELLULAR HEALTH Adipose TissueMETABOLISM Basal Metabolic Rate (BMR)METABOLISM Beta-Hydroxybutyrate (BHB)METABOLISM