High-Fat Diets You'll probably recognize Letitia's Chick-fil-A habit as having two major aspects of the Western diet we discussed in chapter 3--high fat and high- glycemic-index (high-GI) carbohydrates. The Western diet is particularly destructive to PTSD patients, so let's first consider the effects of the abundance of fat (as always, when I talk about high-fat diets, I mean diets high in unhealthy fats like saturated fat, trans fats, and fats used in fried food, rather than healthy fats such as omega-3s or those found in olive oil).When animals consume a typical Western high-fat diet, it makes them more susceptible to PTSD.