I'd go with whichever one has only natural ingredients (which is probably neither! So I'll stick with regular natural peanut butter and pour off half the oil on top before mixing it in!).
you have to be careful here... there are GOOD fats and BAD fats... low fat pb probably has transfats in them.. and tons of sugar... so the BEST peanut butter is NATURAL peanut butter..... it is a GOOD fat! and no sugar!
low carb products are the same way.. they take something away but add something to get it to taste ok...
natural, whole foods are always the best choice!
one exception to the low fat is dairy... low fat cheese and dairy is almost always the better way to go (or non-fat)... but with PB... read the label! and most likely go natural!
oh... just saw that kathryn said the same thing and our answers aren't what you were looking for... but i have to stand my my "neither" answer.... sorry
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cute work out clothes are good for AT LEAST an additional 10-15 calories burned!