Hollstein T, Vinales K, Chen KY, et al. - Since cold-induced brown adipose tissue activation (CIBA) is a determinant of cold-induced thermogenesis (CIT), experts aspired to explore whether thrifty individuals also have reduced CIBA. Twenty-four healthy participants (age: 29.8 ± 9.5y, body fat: 27.3 ± 12.4%, 63% male) were admitted to the clinical research unit and underwent two 24 h energy expenditure (24hEE) assessments to quantify their degree of thriftiness in a whole-room indirect calorimeter during energy balance and fasting conditions at thermoneutrality. A greater reduction in 24hEE during fasting was linked to lower peak CIBA, such that a 100 kcal/day greater decline in 24hEE related to an average 3.2 g/mL lower peak CIBA. The findings show that decreased CIBA is a metabolic trait of the thrifty phenotype that could explain decreased CIT capacity and greater weight gain predisposition in individuals with a thrifty metabolism.