New research out of the Georgia Regents University is showing the effects of a high-fat diet go beyond obesity and the metabolic consequences. When high-fat diets cause us to become obese, they also appear to damage immune cells in the brain. A poor diet causes these immune cells to become sedentary and start degrading neuron connections in the brain. The good thing is, as far as they can determine, the effects appear to be reversible as weight normalizes.
This whole degradation process starts due to the inflammation that occurs from too many fats circulating in the body. This chronic inflammation then stimulates the immune cells to have an autoimmune response. Normally these immune cells are freely circulating, but the increased fat-diet creates a situation in which they start to become immobile and star attacking neuron connections.
As these results were seen in animals, there needs to be similar studies to determine if this effect translates for humans as well. However, if this is proven to be true, this could provide further insight into the physiology of obesity as a disease.
Shuai Hao, Aditi Dey, Xiaolin Yu, Alexis M. Stranahan. Dietary obesity reversibly induces synaptic stripping by microglia and impairs hippocampal plasticity. Brain, Behavior, and Immunity, 2015; DOI: 10.1016/j.bbi.2015.08.023