Animal Trans Fats and Heart Health

As I continue to dig into nutrition, something I’ve become curious about is naturally occurring trans fats found in ruminant animals. Looking at some grassfed lamb at Sam’s Club sent me down this rabbit hole, and I also recall some grassfed burgers at Costco that clocked in with some trans fats.

Anyone out there in internetland known of any decent research or discussions on the topic of animal trans fats and its impact on heart health? I’ve done some rudimentary googling, but I’m smart enough to know when I’m too stupid to know good from bad.


Last I’d read hydrogenated vegetable oils and trans animal fat were 2 very different things. They are chemically different and behave differently in the body. I also remember looking and the amount of trans fat in animal products was extremely low. I don’t think we should panic and tie them nutritionally to hydrogenated oils, but I also haven’t seen anything specifically studying them.

There is some research on carnivore diets coming out and from what I’ve seen, none of them show the type of effects like you see with hydrogenated oils. Biggest thing is we’ve been eating them for several million years so they are probably OK, but I’m open to hearing what other people know on the subject.

1 Like

Most of the stuff I’ve seen is either to complicated or too reductionist too.

1 Like

I very much dig this, but I ALSO know that I have the ability to eat these foods in quantities and frequencies far greater than my ancestors. Whereas they’d get one big kill and feast on it until they couldn’t, I can go back to Sam’s and restock until I run out of funds or their run out of lamb. The whole “the poison is in the dosage” idea.

Appreciate the shared sentiment. I’m very on board the idea that, if nature produced it, it can’t be that bad (within reason of course), but would love to hear from more folks. Hell, even the shared anecdotes are great. You among several other posters always give me great thinking points. And in that regard: I’ve got a bunch of liver in the freezer that needs eating, haha.

Honestly I thought trans fat was entirely man-made. Like I even wrote a paper about it in my high school days because I thought it was an attempt to make a healthier fat than saturated… obviously not the case, but naturally occurring trans fat?

Gonna have to do some research and re-evaluate my life now


Probably depends on location. There were certainly populations that didn’t starve and ate almost exclusively meat.

On that point, the meat today isn’t the same has the meat 2000000 years ago. Pork and chicken are pretty different than wild mammoth. But out of anything you can buy in the grocery store beef is probably the closest food in existence to what we were eating in our evolution, plants included. That doesn’t mean I give it a free pass, but it puts the burden of proof on showing me it’s bad for me.

I know CLA is one of the animal trans fats and it’s pretty toughly studied. You could read up on it for a start, but I don’t think I’ve ever seen anything bad about it.

1 Like

Oh no doubt meat: I’m speaking primarily of the ruminant animals that naturally produce trans fats. From the limited research I’ve done, it’s unique to those specific animals.

Very fair point on meats of the past as well. I’ve been on a bison kick recently and seem to be doing well consuming it. I saw a little bit on CLA from my reading and it seemed like a lot of good stuff for sure.

And FTR I just ate a pound of organ grind.

1 Like

I found this on a quick Googling.

Seems pretty good. I like the way they break the subjects down Kenny Crox style.

The finger points pretty squarely at industrial plant sources as problematic


That’s the exact article I found! Haha. Led me down this initial chase. It was an enjoyable read.

1 Like

I appreciate the Kenny Crox love.


Me too @jshaving :joy:

1 Like

Heathline is awesome, so digestible.

I know almost nothing about this topic but my ruminant consumption has increased over the last few months so I figured I might as well glance at it too.

The below paper concludes, in part, “ Our analysis shows that all three classes of trans fatty acids raise the ratio of LDL to HDL, and therefore, presumably, the risk of coronary heart disease.”

Ruminant trans fat is one of those classes, that paper is pretty digestible (I read 70%, skimmed the rest) and not too long. The number of studies it reviews specifically on ruminant trans fat is disappointingly low but such is life

1 Like

If there is one thing my reading on heart disease has taught me, Cholesterol numbers as a proxy for heart disease is not a good assumption. Not to mention I care about health and all cause mortality more than heart disease and those aren’t always in line the way people would think. I’d rather see HDL and triglycerides which is a better predictor than HDL/LDL. I’m also not a fan of isolated nutrients, I much prefer actual food. This compared swapping monounsaturated fat with trans fat and I’m not sure what actual diets that’s comparing and what that would amount to in food choices.

That said, looking at the data I was far more curious about the HDL affect than the LDL one because I just don’t think LDL in isolation without a lot of other metabolic data means much. As mentioned ruminant data is thin, especially at higher doses. And lower % doses is fairly mixed in result (the lowest doses were actually positive to neutral). There isn’t enough data there to fit a negative trend line. There is lots of CLA data, though again not much at higher doses. And the low dose stuff is all over the map, some hugely positive and some hugely negative. Again, I don’t think the trend line is appropriate with the data.

I think the ruminant side needs more data, especially at higher doses. CLA as a supplement looks all over the place. Overall, just note that the changes they are measuring in cholesterol are tiny. None of the studies showed a large effect even on the not very good indicator of LDL/HDL ratio. And even then, the ruminant fat data is the smallest effect of the 3 types. I don’t see anything concerning about ruminant fat in that data without knowing other factors. CLA either unless you supplementing with larger amounts than you’d get in food.

If you are seriously concerned though, just try it and get your blood work. Look at the bigger picture though: your weight, your insulin sensitivity, triglycerides, inflammation. And also note the sweet spot for all cause mortality and total cholesterol seems to be around 230, contrary to what statin companies will tell you.

1 Like

If you are seriously concerned though

I’m not, just had bloodwork. Total was right around 200 and HDL was in the low 40s, Dr seemed to think everything was fine.

Just interested in the potential effects of severely increased ruminant trans fat consumption, which are (as you mentioned) hard to discern. I imagine other studies have come out since this one but I don’t think I’m going to dig much deeper, tbh.

@T3hPwnisher I know that I’m new-ish around here (LONG time lurker), but for what it’s worth, I’m a registered dietitian by trade and do/have done a bulk of my consulting work in the Paleo/Keto arena. Based on client results - the effect of the animal fats, and really all saturated fats (coconut products, etc.) on lipid profiles is really an individual thing. I’ve had clients that handle it like champs and others whose blood work is totally jacked in a month. Scientific research - just like every other subject out there, you can find pro-sat/animal fat studies and anti. It all depends on what you’re looking for…
I’ve followed your log for almost 2 years now and based on what I see - you tend to do really well with the higher fat levels, but your choices overall are lower on the sat fat side (grass fed meats, avocado, nut butters), so GO YOU!!
I tend to make my recommendations based on the individual but if I knew nothing about a person, I would advise focusing more on monounsatured fats and keep meats lean-ish or grass fed if heart health is a concern or if there is a genetic predisposition to cardiovascular disease.
For trans fats - naturally occurring trans fats tend to be less of an issue than do the man-made hydrogenated chemical shit-storm varieties. That being said, if you’re keeping your overall saturated fat intake low/moderate, there isn’t a lot of opportunity for trans fat in any form to make health-threatening level appearances in your diet.
I’m not sure if any of that made sense, helped or even addressed your initial inquiry - but in my mind it was PURE GENIUS and really, that’s all that matters. :rofl:
Also, if there’s ever any specific info or answers or nutrition opinions that you’re looking for, don’t hesitate to hit me up. I’ve learned A LOT from you over the past 2 years and would be more than happy to return the favor.


I agree with this, though it might not mean much because I’m not qualified in any way. The paleo bug bit me hard in college and so I went down a lot of these rabbit holes. It’s so easy to find people online who claim that ghee cured their awful lipid profiles or that coconut oil must be the sole culprit in spiking their LDL, not to mention all the papers that conflict with each other. Some studies suggest that trans fats specifically from grassfed animals rather than manmade sources may be beneficial. Honestly, as a scientist in training, I don’t care to read more papers in my free time. There are too many other variables in most nutritional studies. Personally, I still eat very paleo-ish, which includes a lot of grassfed meat, and my bloodwork has always been awesome. Would I eat a stick of butter every day, even if it comes from a grassfed source? Nah. I still include a fair amount of unsaturated fats, but I still eat more animal fats than my peers, I believe.


I’ve always found this kind of reasoning weird, to be honest. Because, as you said, the food we eat is different, even if it’s “the same”. Our lifestyles are also different. But most importantly: we’re assuming our paleo ancestors lived long, healthy lives, which they likely didn’t.


Funny thing. Mum sent me an alarmist article (think Sensationalist weibo post).

I think “the poisons in the dose” applies. I don’t think there’s any issue unless you’re eating pounds at a time. Absolute possible, but at that point, I think the bank account would take more damage than the heart given ridiculous prices.

Also, lamb and other ruminants has other nutrients and CLA. Apparently CLA is sold as a fat loss supplement?

I’d say there’s a very clear difference between trans fats from animals and trans fat in processed foods.
I’d imagine it’s similar to the “fructose in fruit” situation

1 Like

There is a reason the zoo feeds animals the same diet they evolved eating.

And you don’t have to go back to paleolithic times to look at similar diets and lifestyles. You can look back just hundreds of years. And yes, health spans of those peoples were better than their western diet counterparts. We have good evidence that cancer, heart disease, diabetes, obesity, etc largely didn’t exist before agriculture. Hunter gatherers were larger, stronger, had less disease, and even had bigger brains than their farming cousins. I don’t want to romanticize their lives which were brutal, but it’s silly to think we can’t learn anything from their diet because many died from falls and snake bites.

And again, this isn’t some hard rule, it’s a perspective. I’m amenable to changing my mind on the health aspects of food, but the burden off proof goes the other way.

On the specific topic it’s also easy to look at US epidemiology and see that animal fats almost certainly aren’t the problem, at least as a general population issue. Animal fat intake has been on the decline the past 100 years and our health has done nothing but get worse.