<P> Factors such as sex, age, population size or other variables may make the equations invalid and unusable, and, as of 2012, Durnin and Wormersley's equations remain only estimates of a person's true level of fatness . New formulae are still being created . </P> <P> Marrow fat, also known as marrow adipose tissue (MAT), is a poorly understood adipose depot that resides in the bone and is interspersed with hematopoietic cells as well as bony elements . The adipocytes in this depot are derived from mesenchymal stem cells (MSC) which can give rise to fat cells, bone cells as well as other cell types . The fact that MAT increases in the setting of calorie restriction / anorexia is a feature that distinguishes this depot from other fat depots . Exercise regulates MAT, decreasing MAT quantity and diminishing the size of marrow adipocytes . The exercise regulation of marrow fat suggests that it bears some physiologic similarity to other white adipose depots . Moreover, increased MAT in obesity further suggests a similarity to white fat depots . </P> <P> Ectopic fat is the storage of triglycerides in tissues other than adipose tissue, that are supposed to contain only small amounts of fat, such as the liver, skeletal muscle, heart, and pancreas . This can interfere with cellular functions and hence organ function and is associated with insulin resistance in type - 2 diabetes . It is stored in relatively high amounts around the organs of the abdominal cavity, but is not to be confused as visceral fat . </P> <P> The specific cause for the accumulation of ectopic fat is unknown . The cause is likely a combination of genetic, environmental, and behavioral factors that are involved in excess energy intake and decreased physical activity . Substantial weight loss can reduce ectopic fat stores in all organs and this is associated with an improvement of the function of that organ . </P>

The main storage site for fat in the body is