25. Metabolic Meltdown
This is not so much an attack on humans as much as it is a horrific problem we’re facing. Metabolic disorders are not uncommon in places like the United States. However, they occur all over the world. Those that cause a decrease in insulin sensitivity can actively reduce cognitive abilities and leave people with fatigue and a lack of regulated energy.
On top of this, your fat cells become less efficient at storing and regulating fatty acids. This allows them into the bloodstream and that causes serious health complications. It even increases cardiovascular disease. The insulin resistance is the first step to diabetes, an inability to regulate glucose, and causes obesity. In essence, this real zombie apocalypse involves people getting obese, lacking energy, and dying off early. All while having cognitive issues overall.