Fat In Your Diet vs. Fat In Your Blood

I received this email from a reader:

Hey Boss!

I hope things are well on the farm. I wrote you several years ago letting you know Fat Head was my entree to LCHF and I ended up losing 300 lbs. and not dying!

So thanks for that.

I wanted to write to share with you a recent real-world refutation of lipophobia. I donate blood plasma twice a week and recently had a diet related issue. As happens for various reasons I haven’t been able to do a low carb diet full on. Recently my father and I went out to a Chinese restaurant and ordered the General Tso’s chicken drenched in sugary sauce, which came on a platter which should have fed a small to medium sized family. Needless to say, I ate the whole thing.

The next day while donating, my blood was thick and goopy with fat to the point where I was nearly unable to even donate. I received several stern lectures on the need to cut back on fat in my diet. I managed to bite my tongue, but I requested their dietary handout (attached) and skeedaddled.

So you have to wait forty eight hours before you can donate again. In the interim I made sure to limit my carbs and up my fats. When the day arrived, I made sure I was well hydrated and went in.

Long story not terribly short my blood composition was excellent. I’m sure this doesn’t shock you, it didn’t shock me, but it is good to rap this bad dietary advice on the knuckles every time it rears its ugly head.

All the best,

Here are quotes from the handout Brian received:

As we performed pre-donation screening tests, or during your donation, we found that your plasma was lipemic. Lipemic plasma contains a high amount of fat. Sometimes the foods you eat may cause excess fats to be present in your blood stream. Lipemic plasma can prolong your donation times and possibly cause you to be deferred from donating.
These are some dietary suggestions to help you avoid lipemic plasma and enjoy a timelier donation.

  • Reduce intake of or avoid high fat dairy products such as whole milk, cheese, egg yolks, cream and butter.

  • Reduce intake of or avoid high fat meats such as organ meats (e.g., liver), ham, sausage, and bacon.

There was further advice to avoid junk foods like potato chips and pizza, and to eat a low-fat meal before the next donation.

Same old, same old. They think saturated fat gives us fatty blood, but the science says otherwise.

In this study from 2011, researchers found that it’s processed carbs that raise the level of saturated fatty acids in the bloodstream, not eating saturated fat:

High CHO [carbohydrate] intakes stimulate hepatic SAFA [saturated fatty acids] synthesis and conservation of dietary SAFA. Hepatic de novo lipogenesis from CHO is also stimulated during eucaloric dietary substitution of SAFA by CHO with high glycaemic index in normo-insulinaemic subjects and during hypocaloric high-CHO/low-fat diets in subjects with the metabolic syndrome.

We conclude that avoidance of SAFA accumulation by reducing the intake of CHO with high glycaemic index is more effective in the prevention of CVD than reducing SAFA intake per se.

Jeff Volek and other researchers reported similar results in this study. Here are some quotes from an article about the study in Tech Times:

People who consciously cut down their intake of saturated fats may be surprised to read the results of a recent study. Carbohydrates had a higher risk for increasing levels of fatty acids in a person’s blood than saturated fats in a small study, recently published in the journal PLOS ONE.

The participants in this study each were given a diet that had the same number of calories — 2,500 — and the same amount of protein. The diets started with higher levels of saturated fats, but every three weeks, the researchers progressively replaced saturated fats with carbs. They found that as the 16 participants ate more carbs and fewer saturated fats, they had increased levels of palmitoleic acid, a fatty acid which is associated with diabetes and heart disease. When the participants ate a diet high in saturated fat and lower in carbohydrates, levels of palmitoleic acid actually decreased.

Brian passed his next screening by eating fat and avoiding carbs. The handout told him to avoid fats, but he knew better. The shame of it is that the supposed professionals don’t know better as well.

p.s. — And in other news … after years of swearing he’d never open a social-media account, The Older Brother has suddenly started popping up regularly on Twitter.  He mostly tweets his libertarian/conservative take on things, so if you’re one of those “I like your posts about nutrition, but I don’t like your politics” types, you’ve been warned.  For the rest of you, check him out at @genaughton57.


31 thoughts on “Fat In Your Diet vs. Fat In Your Blood

  1. gallier2

    What gets me everytime is that it is obvious that fat in the blood, be it for donation or for measurment does not come directly from ingested fat. One only needs to open a physiology book (or the right wikipedia entry). Ingested fat is put in the gut into chylomicrons (i.e. big lipoprotein bubbles), these chylomicrons are transported via the thoracic duct into an put into the veinal system, where it is then transported to the peripheral adipose tissue and muscle cells. This means, the ingested fat exists in the blood only for a short time during digestion, after that it is buried away in the fat tissue.
    But, giving blood is always done in a fasted state, afaict, which means that the triglyceride found in the blood (which are in fact VHDL lipoproteins) cannot be coming from the gut. It doesn’t come from the adipose tissue either, because it release its fat for it to be metabolized in the form of free fatty acids.
    The only source for trigs (VHDL) in the blood when in a fasted state is the liver doing lipogenesis (there’s also the re-esterification of free fatty acids when those are in excess in the blood stream, but these tend to deposit in the gut).

    1. Tom Naughton Post author

      I’m afraid the (ahem) professionals either didn’t read the physiology books or forgot what they read.

    2. Tom Welsh

      The “received wisdom” about nutrition has nothing to do with science. It is politics, pure and simple.

    3. smgj

      Here (in Norway) we’re NOT supposed to donate fasting. They want us to have had both food and liquids before donating.

  2. Kathy in OK

    Years ago I also donated plasma regularly. I remember some of the donors’ plasma looked like yellow Crisco. I didn’t know nearly as much back then, but even then I knew there was something terribly wrong with them. I’m too old to donate now – so they tell me – but I sure would like to see my plasma now.

    1. Tom Naughton Post author

      I had an eye-opening moment during my vegetarian phase: they told me I couldn’t donate because I didn’t have enough iron in my blood.

      1. Firebird7478

        I contracted Hepatitis-A in 1999 which prevents me from donating blood. It is a conundrum, as my mother was told by a doctor back when I was in my late teens that I should donate blood once or twice a year to reduce the high ferritin levels in my blood — the result of weight lifting and meat eating — my blood was too thick and had to be thinned.

        Now they have therapeutic phlebotemy for that, but my doctor doesn’t think it is necessary.

  3. Kathy in OK

    I’ve never felt a need for a Twitter account, but the lure of the Older Brother’s take on things is tempting. Did he ever resurrect his blog?

  4. The Older Brother

    “… after years of swearing he’d never open a social-media account, The Older Brother has suddenly started popping up regularly on Twitter. ”

    Turns out it perfectly matches my attention span.

    But no FB, ever. I’m serious about that one!


  5. chris c

    It’s not exactly rocket science. when you eat so many carbs that you are only able to metabolise glucose – which is toxic in above normal quantities – your body puts the fat aside to metabolise later. If you then eat more carbs, just like you have been told, later never comes.

    Avoid the excess carbs – where excess may be a fraction of what you have been told is “essential” – and fat metabolism works properly again.

    It’s really frightening that “medical professionals” are so unaware of simple physiology, just as you say. Worse still is when you tell them this and they don’t believe you. My GP has learned a lot in the last decade but is still convinced that only fat can raise triglycerides, or make you fat.

      1. chris c

        Oh yes she’s good, not surprising as she worked with/for Ron Krauss. I have a much longer review paper of hers, er, somewhere, oh here from the references


        Trouble is the years if not decades of misinformation by The Annointed. You can lead a horse to water but you can’t make him drink, except by clapping his testicles between two bricks. I’m not sure what is the equivalent for a female GP.

  6. Marshall

    I’ve been eating 3 eggs with cheese for breakfast pretty much every weekday for years. I just had a physical this week and my doctor declared that the numbers on my lipid panel were the best in the building.
    Trig: 59, HDL: 60, LDL: 100, VLDL: 12
    I’m off to a dinner party tonight where I will eat copious amounts of cheese and not feel bad at all about doing so!

  7. Valerie

    A quick Google search reveals that the main contributor to lipemic plasma is chylomicrons. So, yes, dietary fats.

    The problem was probably not so much what Brian ate, but how soon afterwards he donated blood.

    Contrary to what gallier2 said, blood donation is not done fasting. Nurses at blood drives will make sure you have eaten that day and will offer snacks before and/or after the donation to minimize the risk of you passing out. Blood samples for medical tests are often done after an overnight fast, however.

      1. BobM

        Triglycerides are interesting. For me, they vary with fasting, too. I made the mistake of having my “official” blood cholesterol lab work done after 4.5 days of fasting. That was bad! I then took lab tests (both paid by myself) after 12 hours of fasting and after 4.5 days of fasting (i.e., Monday morning and Friday morning of the same week) and found that TC, LDL, and trigs go way up and HDL goes down while fasting. Of course, this guy:


        Has an explanation for this, and has completely changed how I look at cholesterol. I did my tests before he burst on the scene, though.

        If I have another “official” test, I’ll use his technique of low cal/fasting for 3 days then high cal, high fat for three days to get the “best” results I can.

        A note on high fat, though. Anyone listening to the Keto Hacking MD podcast with Jimmy Moore and Dr. Limansky? They tried a 90% fat diet and Jimmy Moore’s markers of insulin resistance (insulin, LPIR) went UP not down. He also had severe hypoglycemia. This goes to show how individualized diet can be. For instance, they went on a 3:1 protein:fat (by grams) diet for a week and both hated it and Jimmy had hypoglycemia after every meal. His blood sugar went DOWN after eating higher protein. Meanwhile, I’ve eaten very high levels of protein (150+ grams) in a single meal and verified with a continuous glucose monitor that nothing happens with my blood sugar (at least that I could see). However, what I’ve been doing is a 36 hour fast, then weights/aerobic workout, then eating very high protein. Maybe that mitigates my blood sugar response? If I eat too much protein and too little fat, I don’t feel good, though. I initially thought this was hunger, but it’s more a general malaise. I also will eat more normally at other means, and I’ve been fasting 36+ hours twice a week and 22 hours once a week, so I haven’t tried an entire week of 3:1 protein.

        Anyway, because of my tests with higher protein, I’ve switched to eating more protein and less fat. But this might not be for everyone.

        1. Tom Naughton Post author

          I’ve listened to the podcasts. The most revealing number for me was Jimmy’s fasting insulin. It’s way high, something like five times higher than Dr. Limansky’s. So anything they try, they’re starting at two very different places metabolically. Jimmy’s body is in something like constant storage mode.

      2. Valerie

        Yes, triglycerides.
        Not chylomicrons.
        The main contributor to lipemic plasma (not to be confused with displipidemia) is chylomicrons.

        1. Tom Naughton Post author

          That’s the part I’m trying to clarify. Science direct says this:

          Chylomicrons (CMs) arise solely from the intestine, and contain TG primarily of dietary origin.

          If they contain primarily triglycerides and a high-carb diet raises triglycerides, wouldn’t we pointing the finger at carbs instead of dietary fats?

          1. chris c

            Indeed we should, but for the memes of Holy Health Grains and Arterycloggingsaturatedfats which need to die first.

  8. Orvan Taurus

    It’s funny (funny-odd, not funny-haha) how pro-low carb folks can point to biochemistry and explain why things work as they do, and pro-high carb have ‘studies’ but no biochemical explanations.

    If you’ve heard Harold Baum’s “Biochemist’s Songbook” the tune ‘Pentose Phosphate Shunt’ starts, “When you’re converting carbohydrates to triglycerides…” Hrrrrrmmmmm.. What gets converted to triglycerides? Hrmm…. but evidently somehow the pentose phosphate shunt pathway must not be very important. Uh huh.

      1. Walter

        The most important thing I learned from Westerns on TV in my youth was, “Great White Father Speak with Forked Tongue.”

        Every child needs to develop a health disrespect for authority.

      2. Walter

        If your doctrines are supported by dogma, you don’t want to examine the facts and should the facts contradict the dogma then you need to suppress your study or at least provide an abstract that supports your dogma.

  9. Diana Donofrio

    This is a true story. When I was in college, my father was following doctors advice and eating a low fat diet. He went in the ER following a minor car accident. Unrelated to the car accident, he had small yellow bumps all of his body. The ER docs were thorough and took a sample to send out for testing. They also took a blood sample. A while later, the phlebotomist came back to take another blood sample telling us that the first sample was contaminated somehow. Then the doctor came in with a terrified look. She told us that my father’s blood was so full of cholesterol that they could see it rising to the top before centrifuging. His cholesterol was the highest they had every seen…it was over 1200. He was sent to be studied at a local teaching hospital because he was told, “no one ever had cholesterol readings that high and lived”. Turns out, the doctors warned him about eating low fat, suggested a low carb diet and even told him about the myth of avoiding food cholesterol. My father used to eat eggs every day and they suggested he go back to his usual breakfast. THIS happened in 1988. So why did the doctors know back then that the cause is high carb low fat diets but doctors are still pushing a low fat diet? I had similar issues a few years ago. I followed doctors’ advice for 10 years and ended up with non-alcoholic fatty liver disease (not a drinker). I wound up with kidney and liver issues, lost my vision, over 100 lbs overweight, severe inflammation/arthritis, high BP and T2 diabetes. I decided enough was enough and went LCHF. I lost 50 lbs in 3.5 months, reversed all but liver issues within a year. My liver took a while longer to heal. Its been years and my A1C, fasting blood glucose and BP are normal.
    When diet is wrong, medicine is of no use.
    When diet is correct, medicine is of no need.
    ~Ayurvedic proverb

    1. Tom Naughton Post author

      Goodness. Those doctors would be risking their careers giving that kind of advice today.


Leave a Reply

Your email address will not be published.