How Bad is Peanut Butter, Really?
Man, you guys really love your peanut butter.
I get at least one email a week from a devoted reader of the blog who just can’t shake the desire (that feels like a need) to eat peanut butter on a regular basis. They’re on board with everything else. They’ve ditched grains and vegetable oils. They’re walking more and getting better sleep. They’re getting sun and eating more vegetables than ever before. They’ve switched to grass-fed beef (sometimes liver, too!) and wild-caught fish. They’ve even happily dumped all the other legumes, except for that persistent, palatable peanut. The more dedicated among them may be soaking, sprouting, roasting, and grinding their own peanuts into peanut butter, but they’re still eating peanut butter – a “forbidden” food on the Primal eating plan.
I’m talking questions like this:
Dear Mark,
I have been following MDA for about a year now and last I week I finally went primal. So far I have not had any issues with giving up grains (no cravings), except I cannot shake my peanut butter addiction! I eat a small bowl full of peanut butter with banana slices for a snack and I know it is awful for me! I eat very healthy foods for the rest of the day (eggs for breakfast, salad for lunch, meat and veggies for dinner) but the peanut butter is probably preventing progress! Help!
Lucy
I don’t want people to feel deprived, nor do I enjoy stripping from them the ability to enjoy their favorite foods, but I also want people to make the best and healthiest food choices possible. To do that, we need to examine the evidence. We need to give peanut butter the rice and oat treatment. We need to figure out whether or not peanut butter is really all that bad. Let’s go, shall we?
First, The Good.
What’s good about peanut butter? Why would we ever want to eat it?
It’s tasty.
I’ll admit it: peanut butter is quite delicious. I’ve never much cared for actual peanuts – they were okay, but not something I sought out – but I’d always grab a spoon or dip a finger for some peanut butter.
It contains nutrients.
It’s food, so of course it has something to it. But what?
Peanut butter is a decent source of thiamin, niacin, folate, and magnesium. It’s actually fairly rich in polyphenols, particularly when roasted (which increases the coumaric acid content considerably). Peanuts also contain small amounts of CoQ10 and resveratrol, though I’d much rather get those from beef heart, sardines, and red wine, personally.
Now, The Bad.
Why should we avoid it? What’s not to like about peanut butter? I’m not even going to discuss the soybean oil and sugar-laden garbage that passes for peanut butter, because my readers definitely aren’t asking about that stuff. They’re doing natural butter with peanuts (and salt) as likely the only ingredient.
It generally contains aflatoxins.
Aflatoxins are naturally occurring fungal toxins, or mycotoxins, produced by certain members of Aspergillus, a type of fungus found pretty much everywhere throughout the world. Aspergillus tends to colonize any monosaccharide and polysaccharide it comes across, as long as the conditions are right, but peanuts are particularly susceptible. Most crops are colonized after harvest and during storage, but since Aspergillus is found in the soil (among other places) and peanuts grow underground, peanut colonization often occurs well before harvest. The result is that peanuts are among the most contaminated crops, along with corn and cottonseed.
I wrote about the negative effects in a previous post, which I’ll sum up for you:
Aflatoxin, being a toxin, is metabolized by the liver. Large enough doses of aflatoxin are a liver carcinogen in high doses (it’s actually what T. Colin Campbell used to induce liver cancer in mice during his China Study crusade to indict animal protein). Early exposure and elevated bloods level of aflatoxin are associated with stunted growth in children.
Interestingly, it seems that the peanut butter-making process dramatically reduces the aflatoxin content of the initial peanuts, by around 89% (PDF). In the study, roasting at 160 degrees C reduced aflatoxin by 51%. Blanching, or skin removal, reduced it by 27%. Finally, grinding the peanuts into butter removed another 11% of the aflatoxin, probably because of the heat (not the actual grinding). So if you’re going to eat peanuts, stick with a good butter.
It contains peanut agglutinin.
As of now, the harmful effects of peanut agglutinin, a peanut lectin, are mostly speculative, but still compelling:
- In isolated human colon cancer cells, peanut lectin is a mitogen, or growth-promoter. You generally don’t want cancer cells to divide and increase in number.
- Altered glycosylation may be at the heart of inflammatory bowel disease-related cancers, like colon cancer.
- Peanut agglutinin causes colon cancer cell proliferation via altered glycosylation, in an in vitro study.
That said, those are just in vitro studies. They don’t tell us what happens when peanuts are eaten. However, in real live human subjects who ate real peanuts, peanut agglutinin has been shown to make it through the gut lining to end up in the blood stream. That’s a little worrisome, don’t you think?
I want to reiterate, though: eating peanut butter has never been causally linked to the development of colon cancer. In fact, one epidemiological study found that frequent intake of peanuts and peanut products was linked to a lowered incidence of colorectal cancer in Taiwanese women.
It might contain a uniquely atherogenic oil.
Yeah, peanut oil has a good amount of monounsaturated fat, about 46.8% of the total fatty acid content, which has earned it a solid reputation for heart health in the conventional health world. But it’s also got a significant amount of PUFAs, too. 33% of the total fat is omega-6 linoleic acid, with an essentially nonexistent omega-3 ALA content. You could say that about a lot of nuts, though, and I don’t think the PUFA content is the big determinant here. It doesn’t help, but it’s not a deal breaker on its own. Let’s dig a little deeper.
Peanut oil has favorable effects on standard lipid panels. LDL drops, total drops, total:HDL ratio drops. The jury is out on how much that all matters, but eating peanut oil will probably make your cardiologist happy. Awesome, right? Maybe, but peanut fat appears to be uniquely atherogenic despite the lipid effects. For decades, it’s been used by scientists to induce atherosclerosis in cholesterol-fed rats, rabbits, and primates. Some researchers think that peanut lectins, present in the oil, are the cause of the atherogenicity. Reduction of the lectin content of peanut oil, through “vigorous washing,” also reduces the atherosclerosis it causes (although not completely).
You know what else reduces the peanut lectin content? Not eating any peanut butter.
It’s a little too tasty.
There’s something about the combination of fat, salt, protein, and smooth scoopability of peanut butter that promotes overeating. I wasn’t able to bring up any concrete studies on the pro-bingeing effects of peanut butter in humans (though if you run a Google search for “peanut butter addiction,” you’ll get a bevy of testimonials from all sorts of people claiming to be addicted to the stuff), I believe it. And I bet obesity researchers who typically work with rodents would believe it, too, since peanut butter is often used in these studies as a high-reward, obesogenic comfort food that rats and mice will readily and consistently overeat.
Ultimately, to feverishly scoop in a ravenous frenzy or not to feverishly scoop in a ravenous frenzy is a choice you have to make. I wouldn’t recommend eating peanut butter very regularly, and I know I won’t for the reasons mentioned above, but that doesn’t mean you have to follow suit. The inclusion – or exclusion – of peanut butter (or peanuts in general) will not make or break your Primal cred. There are a lot of things you want to have under control before obsessing over peanut butter, like grains, omega-6 oils, sleep, exercise, play, daily low level activity level, quality of meat, etc. You get those under control and then start thinking about some peanut butter as a treat every now and then, if ever.
As I see it, the easy answer is to just not eat it, because I don’t see anything at which it particularly excels (besides inducing people to eat the entire jar in a single sitting). You can get your polyphenols and your minerals from fruits and vegetables, your monounsaturated fat from meat, olive oil, mac nuts, and avocados, and your smooth pulverized salty nutty fix from almond butter, mac nut butter, coconut butter, or any other nut butter – without the peanut lectin, the weirdly atherogenic fat, the aflatoxin load, or the insatiable desire to eat more and more and more until it’s all gone and your forearm is sticky.
Of course, it’s easy for me to say: I don’t have a peanut butter habit.
Anyway, let’s hear from you guys. Do you eat peanut butter? Are you addicted? Are you able to stop with just a bite or two? And most importantly, has your peanut butter habit negatively affected your results? Let me know in the comment section!
Get the Primal Blueprint Fitness eBook, Free Health Tips and Primal Recipes Delivered to Your Inbox













I can eat pounds and pounds of smoked wild salmon (and I probably would keep eating as long as it was in front of me). Incidentally, this is also how I keep the O3:O6 ratio where it needs to be (after all the peanut butter I eat!)
Americans eat over 700 million pounds of peanut butter; we do this because it helps replenishing some of the needed nutrients. Peanut butter has very good sources of polystutrated and monosturated fats. It can also help you lose weight by eating a spoonful of peanut butter it can curb your appetite. Peanut butter is also packed with nutrition that we lack in such as zinc, potassium, copper, and magnesium.
What Mark says in this blog about peanut butter is true. I haven’t purchased peanut butter in two decades due to the reasons he has listed here. Additionally, I recommend to my patients to do the same. That said, I have tasted it here and there and my oh my it is good!
I do not like almond butter AT ALL. It’s just too bland and thick. But I LOVE sunflower seed butter. Trader Joe’s has a one-pound container for $5. It’s creamy and rich! Despite at one point having a full-blown Whole Foods 365 brand peanut butter addiction a few years ago, I can’t even eat peanut butter anymore. Consuming too much peanut butter slowed my digestion to a halt. It got the point where I was expelling waste that literally looked just like peanut butter. It was unsettling, and a wake up call that maybe regular peanut butter consumption is a bad idea. But since I’ve found the reasonably-priced sunbutter, I don’t even want to go back, and my digestion is back to normal. It’s must closer to peanut butter in taste than almond or cashew butter.
I think if you can have peanut butter in moderation, there really isn’t a big issue. I mean c’mon, there are worse things out there. It should be used as a treat instead of a habitual thing.
Hey everyone! So there’s an organic nut butter out there called “Nuttzo”, anybody else heard of it? It is a 7 nut/seed blend that even is infused with dark chocolate. However, the first ingredient is … Drum Roll … Peanuts!!
So my question to you Mark or any of you primals is … Is this safe to eat? It claims it has a healthy amount of ALA omega 3 fatty acids as a disclaimer.
I would love to hear your guys’ thoughts!
To eat.. Or not to eat. Cheers!
D: No peanut butter? For real?
This is going to have to be my one regular non-Primal indulgence. Grok can’t take my precious peanut butter, haha!
Two years ago, started having a breakfast of green tea with a bowl of oatmeal, buckwheat or 10 grain hot cereal for breakfast, with a generous scoop of peanut butter, and added cinnamon, turmeric, pepper, olive oil, raisins and berries, and some almond or soy milk. Currently weigh about 33 pounds less than two years ago and have maintained that weight. Also eat peanut butter during the day on sandwiches, snack on walnuts and pistachios..
About a year and a half ago, I read an article on a triple play way of cutting body fat, where there were three classes of foods that eaten together were 10 times more effective at reducing body fat that each one separately. Peanuts were one type, oatmeal was in a second group, green tea was in the third group. Turns out the morning bowl of hot cereal combined the major fat blasting foods in the right proportions.
I also do interval training using a soccer ball, or martial arts, or walking up and down hills, which do doubt is responsible for some of the weight loss and control.
My old weight (220) was due, in part, to eating peanut butter out of the jar on a spoon, and a just before bedtime peanut butter sandwich. Stopped eating PB out of the jar, and cut down on the late night PB sandwiches.
Your article is a bit scary to someone who eats a lot of the stuff. Maybe I should reduce the PB substantially. Some health experts say eat all the nuts and seeds you want. My total LDL/HDL is about 170, which may not be especially good.
Well, peanut butter contains a lot of zinc and protein. Try it a couple of hours before an exam or some deadline, better than chocolate, you will be working non-stop for hours. All that zinc.
I think if it is organic and from toasted peanuts, small amounts of peanut butter once a week should be ok. Chewing it carefully before swallowing will reduce its carbs load. Keeping it in the fridge will reduce mold as well.
No nuts should be consumed in large quantities, Too moldy.
aflatoxin is generally only a problem in high humidity areas like south africa and the like. in canada, the states and uk, peanuts below our standard (higher potential for contamination) are actually shipped to other poor countries. i don’t think aflatoxin is a huge worry here, especially if youre grinding it up yourself into a tasty pasty!
I absolutely LOVE peanut butter, and have no control once the jar is open – which isn’t a good thing for me or my kids. So we stick with cashew butter and mac nut butter, on an occasional basis.
I prefer sunflower butter now; used to love peanut butter but felt the potential for bingeing was indeed more enhanced than other foods. Also, my body doesn’t handle peanut butter (or most nuts and nut based foods) well. Enjoyed reading your article!!
W100% Almond Spread
Wholemeal bread, 100% almond spread, slices of banana and a very small drizzle of honey…. PERFECT!
Teach your kids from an early age!
Thanks for the article.