Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
17 May

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!


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 oilmac 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!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. You all do know that almonds (though peanuts are a bit higher) also contain aflatoxins; along with many other everyday foods such as:

    “Aflatoxins are detected occasionally in milk, cheese, corn, peanuts, cottonseed, nuts, almonds, figs, spices, and a variety of other foods and feeds . Milk, eggs, and meat products are sometimes contaminated because of the animal consumption of aflatoxin-contaminated feed . However, the commodities with the highest risk of aflatoxin contamination are corn, peanuts, and cottonseed.”

    Also, vitamin C is “thought” to naturalize the fungi…

    Michelle wrote on January 7th, 2014
  2. I don’t drink, don’t smoke, don’t eat candy, don’t eat carbs in anything other than small amounts. I’m 64 years old and maintain 11% bodyfat…as I have since I first did Atkins in the seventies.
    Primal eating was an easy transition for me…with the exception of peanut butter. I still eat Jif (gasp) once per week and I eat a lot of it….about 1/4 of a small jar.
    I’ve tried cashew butter but find that it is entirely too tasty and would cause me to eat the entire jar throughout the day. Almond butter doesn’t do a thing for me.
    To me, life is too short to give up some foods and for me that food is peanut butter.

    Emory wrote on March 28th, 2014
  3. I was just looking for the skinny on Peanut Butter & came across your article. I’m not a subscriber but I thought I’d comment. I’m not addicted to Peanut Butter or any other food for that matter. I do adher to a pretty nutritionally sound diet. In the morning I mix up a smoothie consisting at times of, you guessed it, Peanut Butter. Once in a great while I indulge in a tablespoon. I will continue to educate myself & make changes in my nutritional choices. I look forward to what those will be & in the meantime I’ll enjoy Peanut Butter.
    Thanks for the info. God Bless!

    Teresha wrote on April 20th, 2014
  4. I don’t understand this. Almond butter is ok for paleo but peanuts butter isn’t ? Almonds have lectins and afloxins as well. Why is almond butter ok?

    joe wrote on May 16th, 2014
  5. Thanks for the tips on peanut butter. I use to make peanut butter, on wheat bread with banana as a power meal before going to the gym. Now I will use just banana, avocado on wheat bread. Thanks again.


    Rudy wrote on June 2nd, 2014
  6. I just had a shrimp spring roll from Trader Joes that came with peanut sauce. I feel horribly guilty! the peanut sauce was amazing… good thing I don’t eat peanut butter on a normal basis, this just happened to be included….

    Jackie wrote on June 4th, 2014
  7. I once also thought Maranatha almond butter tasted rancid..till I added in my own amount of sea salt and that did the trick!! I highly recommend adding it in! I used to be quite dependent on PB for my apples and bananas, but almond and sunbutter taste waaaaay better with those fruits so it was an easy switch! Every now and then I will have a little PB but not overdo it.

    Mel wrote on June 10th, 2014
  8. Wow lots of comments. People around here are nuts for the stuff. Will anyone even read this? (For Mark – feel free to skip this comment, it’s really not important, but my compulsion to communicate some minutiae is currently in control).
    I wanted to come back to this post because I’m eating some peanut butter now and don’t think I’ve yet stated my opinion here on peanuts: they are primal even if they are technically a legume and may be harmful. Grok would have eaten them. (Grok probably would have eaten anything that tasted good.) They don’t require processing and are suitable for long term storage if they aren’t infected with the fungus.
    I don’t eat a lot of peanut butter or peanuts or even nuts in general anymore. There are times that I have eaten loads of PB, including the industrial death paste, but usually that was before I knew better or when there wasn’t better food available for what I needed (mainly protein). I have succumbed to pure temptation on occasion. I used to eat large amounts of peanut-based trail mix as a staple and got a significant amount of my protein that way. One of the good things about that was that I was eating a fairly high-fat diet as a result before I knew anything about high-fat diets, even if I was getting huge amounts of omega 6.
    Besides all the well-known reasons to limit peanut butter intake I don’t eat a lot of it or nuts anymore and rarely buy any because I find them tough to digest sometimes and I usually prefer other foods. When I had seriously worrisome digestion before they’d practically go through me unaltered, or at least a good portion would. I might as well have chewed them up and spit them out but I kept eating them hoping things would improve, which didn’t happen until much research and many changes later – different story though. I need to make sure I’m not stuffing myself with other foods when I eat nuts or not eat anything for a while after eating them so that I don’t force them through my digestive tract too fast and I find that it’s best not to mix them with most other foods. I seem to be able to handle them alright with some other plant food or a little bit of cheese, again if I give myself enough time to let peristalsis happen at its own pace, and I think I digest nuts best by themselves.
    I eat nuts and nut butter now occasionally as a snack/filler or small meal and for some variety in my diet, especially when I want some minerals, otherwise I generally lean towards meat/fish and vegetables as my basics (as most of us probably do). I like refrigerated nut butter with a natural sweetener mixed in as a treat now and then, which is how I’m consuming the peanut butter now: in a bowl mixed with maple syrup. Often when I do this I’ll keep scooping away until pretty much all of a sudden it doesn’t taste that palatable or seems too sweet and I don’t want any more for a while and almost get a gag reflex if I try to force more in. I also prefer nuts at night. They seem to be a relaxing food when I don’t really need to eat and just feel like munching, particularly pecans, which in large, filling amounts I’ve found quite sedating. I don’t know what it is about them. Maybe magnesium plays a role.

    Animanarchy wrote on June 23rd, 2014
  9. I really can’t understand the ‘omw i could totally eat a jar’ comments. Sorry folks :)
    But I do keep some peanut butter – because it cooks up amazingly with chillis. Yep, Asian food addict here.
    Occasional white rice and soy sauce (proper brewed stuff, not that horrible travesty made with HVP) are the other ‘cheat’ items allowed in my food supply.

    This primal thing is more complicated than it looks – surely Grok ate a few primitive grains and legumes?

    Primal has made a huge difference already (just over 1 month primal). Less belly fat (I was on meds that promote abdominal lard), more energy, calmer nerves, and a better tolerance for stress/disrupted routine. Not that that’s to be sought, but when one is a teacher with +- 300 scripts to mark in 1 week, lack of sleep happens. And a high sat fat, high meat, high veg diet has kept me coping *much* better>

    David Franklin wrote on June 25th, 2014
  10. I just ate some peanut butter because I ran out of my cashew butter which is amazing trader joes started selling their salted cashew butter in the ingredients all it is is almonds and cashews its so creamy and good lower fat content than almond butttwr as well but today is the only and last day I stick a couple of teaspoons into that peanut butter jar. I havent had peanut butter since I started eating primal which is about 5 months now. Oh well no ones perfect.I highly recommend cashew butter though. Its so good

    Ruben wrote on August 13th, 2014
  11. I’ve made my own peanutbutter and I just tried making some almond butter and both take me around 20 minutes in total to make. Almond butter tastes pretty damn good but so does peanutbutter…and raw peanuts cost about $1.5/kg here whereas raw almonds cost $12/kg….so yeah…I’m trying to gain muscle mass so adding 2 tablespoons of each a day would be very beneficial, but peanuts are sooo much cheaper than almonds

    James wrote on October 3rd, 2014
  12. I’m primal and I still eat peanut butter well a special kind which its called Hawai’is North Shore Macadamia nut coconut peanut butter the ingredients include: peanuts macadamia nuts coconut honey and thats it is it unhealthy because I love it so much plus its made from Hawaii.

    bri wrote on October 7th, 2014
  13. I am super bummed to learn these horrible things about peanut butter. Nothing makes me feel more energized in the mornings than apples and peanut butter :/

    sarah pearson wrote on January 1st, 2015
  14. Thank you for this interesting post! My man is addicted to this stuff and I am a little worried. He doesn’t seem to have a negative side effects. But that doesn’t mean anything I guess. While I never cared much for this stuff, lately even I have started to dip the spoon into jar. I definitely have a stronger will-power though and will try to stay away from it…;) One of my worries also is the high phytic acid content which can be troublesome for an appropriate intake of important minerals. What do you think about that?

    Yana wrote on February 4th, 2015
  15. I have hashimotos and was strictly instructed not to eat nuts for obvious food sensitivity reasons. I was good and listened but craved peanuts and peanut butter the whole time. After a few months of gelatin and gut healing I indulge in a tablespoon of organic roasted peanut butter (no salt – add my own pink himilayan crystal salt) once a week or every two weeks. I don’t touch eggs at all or any grains or gluten containing foods and stay away from dairy too except for some organic dark chocolate. I exercise 4 times a week, have fixed my sleeping, am losing weight and digestion is improving… have to live at least a little once a week. It can be a mental reward for over coming a chronic illness. peanut butter is my therapy 😛

    Tenille wrote on February 26th, 2015
  16. Forgive me for commenting on such a dated post. I’ve been primal for the best half of 4 years. Almond butter was used and enjoyed splendidly in my house from the beginning. Just fine. Even better than. no problem. I even preferred it over PB. like many other readers. Then all the sudden, coming home from an intense workout and scavenging through the fridge, I find no almond butter, but there’s a jar of organic Peanut Butter. So I say what the heck and have at it. Next thing I know, 4 weeks later and I’m shoveling Down PB at a Jar a week. One whole jar of Pb to myself. Weekly for the last month. Maybe longer. This stuff is madly addictive to me and I’ve never experienced any kind of food addiction before this and have had no issues cutting out sweets, grains, Whatever. But this PB. Just a heads up to anyone Who may stumble onto this as I Did, I am now as of the last week, lately finding myself feeling bloated, stuffed up and less than great. I’m certain it’s the PB. Don’t do It. Lol. or do, and suffer the qualms.

    AddictedGrok wrote on April 22nd, 2015

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