This episode explores the diet and lifestyle habits of perpetually lean individuals, contrasting them with common misconceptions about fat loss. Thomas DeLauer shares insights from his surveys, highlighting the significance of non-exercise activity thermogenesis (NEAT), particularly fidgeting, in burning calories and stimulating muscle contraction. Against the backdrop of structured eating routines, the discussion pivots to the benefits of unstructured meal timing, where individuals "forget to eat," leading to random caloric deficits. More significantly, the conversation explores the controversial "sugar fasting" trend and the role of fibroblast growth factor 21 (FGF21) in metabolically healthy individuals. As the discussion pivots to practical advice, the importance of being deliberate about fat intake and mindful eating habits is emphasized. The episode concludes by touching on the potential benefits of vitamin D and time spent outdoors, as well as the surprising habit of incorporating smoothies into the diets of naturally lean individuals, challenging conventional wellness advice.