When people started replacing butter and lard with processed oils and fats, it took a long time for scientists to notice that this change was making people more inflamed and sick with long-term diseases.

If you swap out natural fats from animals (like butter or lard) for man-made or heavily processed fat substitutes, your body might not get the special fat molecules it needs to keep cells healthy and send proper chemical signals.

Human physiology is evolutionarily adapted to metabolize and utilize animal-derived saturated and monounsaturated fats as primary dietary lipids.