The Journal of Lipid Research, reports on research which indicates that in obese individuals, fat cells are bloated and inflamed because they receive too many nutrients, including lipids. In these cells, various components cannot work properly anymore and, instead, they activate new proteins to cope with the situation.
Researchers show that when a fat cell receives too many nutrients, the ER is overwhelmed and triggers a process called the unfolded protein response (UPR). This process is one of many cellular responses that activate proteins that increase inflammation and can even result in the death of the cell. UPR also causes insulin resistance, a condition in which the production and function of insulin – a hormone produced by the pancreas – is impaired and blood sugar is too high.
In English: too many calories heading to your fat cells leads to inflammation and insulin resistance.