According to their website, Skippy brand peanut butter does not contain trans fat.

However, the current label for their chunky peanut butter contains the following ingredient in the listing: Hydrogenated Vegetable Oil (Cottonseed, Soybean and Rapeseed Oil) To Prevent Separation.

Soybean oil is a known source of trans fat, which can be a source of atherosclerosis – the clogging of arteries with plaque – which can be a cause of heart attacks.

Is their website just blatantly lying about the lack of trans fat?

  • 7
    Could it be that local law allows "...has zero grams per serving." meaning "...has less than one gram per serving."?
    – npst
    Commented Feb 25, 2019 at 14:58
  • 5
    I thought hydrogenated oils was trans-fat, not just soybean oil. So hydrogenated canola (rapeseed) oil would also be trans-fat, right?
    – Chloe
    Commented Feb 26, 2019 at 16:03
  • 2
    Are you sure the soybean oil is partially hydrogenated? Where does it say that? Commented Feb 27, 2019 at 4:44
  • 2
    Trans fats are not entirely unnatural. They can develop at low levels during mechanical processing and product storage from the original form. So without legal permission to use 0 to represent "negligible" or "trace", it can't ever be strictly true. Such levels are not a health hazard -- "The poison is in the dose". Of course, the levels in chemically partially hydrogenated fats are completely off the scale of natural occurrence, and do represent a health hazard.
    – nigel222
    Commented Feb 27, 2019 at 10:58
  • 2
    It's worth noting that the FDA has determined that Partially Hydrogenated Oils are not Generally Recognized as Safe (or GRAS) and has established rules for their elimination from the US food supply: fda.gov/food/ingredientspackaginglabeling/… If any foods still have trans-fat being added to them, they won't for long; they are being removed from all foods
    – Flydog57
    Commented Feb 27, 2019 at 23:38

3 Answers 3


According to their website, Skippy brand peanut butter does not contain trans fat.

Strictly speaking, according to their website, Skippy brand peanut butter contains a negligible amount of trans fat. Per the US FDA,

The Nutrition Facts Label can state 0 g of trans fat if the food product contains less than 0.5 g of trans fat per serving. Thus, if a product contains partially hydrogenated oils, then it might contain small amounts of trans fat even if the label says 0 g of trans fat.

So they're being sneaky, right? Not really. The amount of trans fat in a serving of peanut butter is far less than the limit of 0.5 grams that needs to be reported as above zero. Only a tiny amount of hydrogenated vegetable oil is added to peanut butter to make it smooth, prevent separation, and drastically increase shelf life, and only a small amount of that small amount is in the form of trans fat. While non-zero, the amount is essentially undetectable. From Sanders, T.H., 2001. Non-detectable levels of trans-fatty acids in peanut butter. Journal of agricultural and food chemistry, 49(5), pp.2349-2351,

The fatty acid composition of 11 brands of peanut butter and paste freshly prepared from roasted peanuts was analyzed with emphasis on isomeric trans-fatty acids. No trans-fatty acids were detected in any of the samples in an analytical system with a detection threshold of 0.01% of the sample weight. Hydrogenated vegetable oils are added to peanut butters at levels of 1--2% to prevent oil separation. Some hydrogenated vegetable oils are known to be sources of trans-fatty acids in the human diet. The addition of these products was not found to result in measurable amounts of trans-fatty acids in the peanut butters analyzed.

  • 28
    This is similar to the reason why Tic Tacs are labelled as sugar-free, despite consisting of almost nothing but sugar. Commented Feb 25, 2019 at 18:41
  • 65
    @JanusBahsJacquet I don't think it's remotely similar. The serving size for Tic Tacs is 0.49 g (1 mint) so it couldn't possibly be above 0.5 g sugar per serving, and it is in fact mostly sugar. That is an extreme example highlighting the problem with setting these limits relative to serving size, which is a somewhat arbitrary concept (who eats just one Tic Tac?) . For Skippy peanut butter on the other hand, the serving size is 32 g, so less than 0.5 g trans fat means less than ~1.5%, and the study linked to in this answer shows that actual levels are less than 0.01%.
    – jkej
    Commented Feb 25, 2019 at 19:35
  • 31
    @JanusBahsJacquet, No, it's very different. Tic Tacs are 91% sugar by weight, but since a Tic Tac "serving" is less than 1/2 gram, Tic Tacs have less than the reportable amount of anything. Peanut butter on the other hand contains less than 0.01% trans fat by weight. You'd have to eat an institutional-sized jar of peanut butter as one serving in order to consume 0.5 grams of trans fat. Commented Feb 25, 2019 at 19:35
  • 22
    @jkej Actually, it’s not only similar, but identical: the reason in both cases is that the limit is ‘hard-coded’ at 0.5g regardless of percentual content. In both cases it leads to misleading labelling, it’s just much more misleading. Naturally, the situations are very different between the two, but the underlying reason is the same. Commented Feb 25, 2019 at 19:42
  • 11
    And if anyone is curious about the italicization: english.stackexchange.com/questions/170273/… Commented Feb 25, 2019 at 23:37

I note that the label says "Hydrogenated Vegetable Oil" not "Partially Hydrogenated Vegetable Oil". If the oil has been fully hydrogenated it no longer contains trans fats, by definition.

Unfortunately you can't know whether an oil has been fully or partially hydrogenated when the label omits those qualifiers. It seems highly likely to me that the manufacturer did this intentionally to avoid the negative stigma associated with partial hydrogenation. It would be wise to assume partial hydrogenation when "Fully" is absent.

A fully hydrogenated oil by itself will be solid at room temperature but I cannot say what would happen to an fully hydrogenated oil suspended in a matrix of peanut bits.

http://www.berkeleywellness.com/healthy-eating/food/article/hydrogenated-oils for more information on hydrogenation and health.

https://www.nationalpeanutboard.org/wellness/why-you-shouldnt-be-scared-oil-in-your-peanut-butter.htm for a highly biased take on the oils used in peanut butter across the industry.

  • 2
    "It seems highly likely to me that the manufacturer did this intentionally to avoid the negative stigma associated with partial hydrogenation." But partially hydrogenated oil typically consists of 30-40% trans fat and according to the study cited in David Hammen's answer, peanut butter typically contains 1-2% hydrogenated vegetable oil. That would give 0.3-0.8% trans fat in the peanut butter, but the study couldn't detect any trans fat (with a detection limit of 0.01%). So either it's fully hydrogenated, or they have some way of doing partial hydrogenation without producing trans fat.
    – jkej
    Commented Feb 25, 2019 at 20:16
  • 2
    So perhaps the marketing directive behind omitting the partial/full qualifier is "keep the ingredient list as short as possible". Commented Feb 25, 2019 at 20:23
  • 2
    Interesting. JIF's labeling makes a point of stating that theirs is fully hydrogenated. Perhaps Skippy's is a blend of fully and partially. Commented Feb 25, 2019 at 23:34

Under US law, if a food label says "hydrogenated oil" instead of "partially hydrogenated oil", that must refer to fully hydrogenated oil. By definition, fully hydrogenated oil contains no trans fats. Trans fats are defined by the locations where hydrogen atoms do or don't bond with carbon atoms; once the oil is fully hydrogenated it becomes a saturated fat instead.

Assuming that the ingredient list is complete and accurate, and the oil has been processed as intended, the product in question should contain zero trans fat.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .