Final answer:
Brown adipose tissue in obese individuals is less prevalent and possibly less active than in lean individuals. This tissue, rich in mitochondria, is crucial for thermoregulation by generating heat through non-shivering thermogenesis, which can be less efficient in obese people due to their higher amounts of white adipose tissue.
Step-by-step explanation:
Brown adipose tissue (BAT) is a specialized form of fat tissue that is primarily involved in thermoregulation. In infants, BAT is abundant and helps in regulating body temperature due to their higher surface area to mass ratio which leads to greater heat loss. BAT is characterized by its high density of mitochondria which contain a protein called thermogenin that enables the tissue to produce heat rather than ATP. This process is called non-shivering thermogenesis.
In obese individuals, BAT is less prevalent or may be functionally different. Contrary to popular belief, adults can have BAT, particularly those who are exposed to cold environments regularly. The difference in obese adults might be that the BAT is not as active or as effective in metabolizing fats for heat production, and instead, larger amounts of white adipose tissue (WAT) accumulate, associated with energy storage rather than energy expenditure.
This could in part explain the difference in energy metabolism between lean and obese individuals. The presence and activity of BAT in adults are linked with a higher metabolic rate, and decreased presence might be associated with obesity due to less energy being expended in the form of heat.