At birth, most human fat tissue is heat-producing fat with many brown, thermogenic adipocytes. This type of fat tissue is called beige adipose tissue (BeAT). As the baby grows into a young adult, this switches so that the fat tissue is predominantly of the fat- and energy-storing type called white adipose tissue (WAT). White adipose tissue is so named because the fat cells are full of clear lipid droplets. Beige adipose tissue has fat cells with many mitochondria and small lipid droplets. The abundant mitochondria give these cells their “dark” color.
Read more:
N. R. Gough, Signal or Nutrient: Breast Milk Lipids in Macrophages. BioSerendipity (December 2019) https://www.bioserendipity.com/signal-or-nutrient-breast-milk-lipids-in-macrophages
N. R. Gough, Researchers Find a Special Lipid that Controls Fat Development in Babies. Medium (18 October 2019).