SCIENTISTS who have traced the origins of so-called "bad" fat in the body say the discovery could help to understand and treat obesity.
A team from the Medical Research Council's (MRC) human genetics unit at Edinburgh University discovered that visceral fat – which forms around vital organs such as the heart and intestines – originates in the embryo.
Although all fat carries health risks, hidden visceral fat is said to be a much bigger threat than subcutaneous fat, which sits under the skin.
It can increase the risk of cancer, type 2 diabetes, heart disease and Alzheimer's disease.
In contrast, subcutaneous fat – "good" fat – can be beneficial because it provides energy, cushioning and insulation.
Professor Stephen Hill, of the MRC's molecular and cellular medicine board, said: "Visceral fat can be a silent killer because it's possible to have a lot of it without looking fat on the outside."
The study is published in the journal Nature Cell Biology.