On mobile so sorry for no links. "Fat is bad" is untrue. Watch any of the plethora of anti sugar films and you can get a brief history on the sugar lobby in the US and how fat's link to cardiovascular disease is limited. Salt is also not a problem, but it depends on your water intake and exercise (ie sweat) levels. Obviously, a pure fat and salt diet might not be the best choice, but both are solid parts of a healthy diet, especially if one is striving to be strong and fit.
Fat isn't bad per se. Excessive fat consumption however is as are saturated fats.
Peanuts mostly contain unsaturated fats. Peanut butter though might contain all sorts of other ingredients that are rich in saturated fats (like some plant oils).
The problem with salt is that in general Western diets already tend to use too much salt and too much salt can lead to an increase in blood pressure, which ultimately if untreated can lead to heart attacks and strokes.
