Pure peanut butter is incredibly healthy, AND it has a ton of calories. No one said those two things were mutually exclusive.
It’s the other ingredients they put in packaged peanut butter that are not peanuts that you have to watch out for. Andrew mentioned high fructose corn syrup, the other one is hydrogenated oils. They add these to keep the peanut butter from separating. The only problem with them is they contain transfat.
And yes, the new FDA labeling system requires manufacturers to include grams of transfat in nutritional facts, however, they are allowed to write “0” if the product contains less than 500 milligrams per serving.
This is all well and good except that transfat is easily as bad as or worse for you than cholesterol, and only 300 milligrams of cholesterol is considered the maximum a normal person should consume in one day (cholesterol’s “daily reference value” according to the FDA).
The moral of the story is, read the ingredient listed, and don’t buy peanut butter (or anything) with the word “hydrogenated” anywhere in the list.