Why Do We Need Fats?

One of the hardest things for me to accept when I transitioned from a vegan diet to a more ancestral one was the role of saturated fat (especially the fat from animals) as well as cholesterol in my body. I had gone a decade believing that because I ate a purely plant-based diet free from cholesterol and animal fat that I would avoid cancer, heart disease, and other major illnesses. This belief was bolstered by the popularity of books like The China Study and documentaries like Forks Over Knives. While I became more and more obsessed with justifying my biologically unnatural diet, I ignored the early warning signs of the autoimmune diseases that were developing in my body. Little did I know that eating a diet completely devoid of cholesterol and fat was setting me up for a harder struggle down the road. I believed so strongly that veganism was the answer to every health problem, and as I got sicker my diet got more strict as I tried every cleanse and variation of the raw vegan diet.

At one point it became obvious to me that I was doing something wrong, and my suffering had become so great that I was finally open to the idea of changing my diet. As I have written about at length in this post, when I started eating meat again I recovered very quickly in a lot of areas – it only took a few months to regain sufficiency of most of the major vitamin and mineral deficiencies that had plagued me for years. One of the areas I struggled with even after months of diet change was fatty acid status. It wasn’t until I started studying nutritional therapy that I learned of the important roles of fats in the body, and why some of my lingering symptoms could be attributed to being on a low-fat diet for a very long time.

I wanted to share a list of beneficial roles that fats play in the body from the excellent book Know Your Fats by Mary Enig:

  1. Fats make up cell membranes. An extreme importance is placed on the quality of these cell membranes, because if they are made out of the wrong type or low-quality fat it will directly impact the functioning of the cell. Cholesterol is necessary in cell membranes to give them a flexible structure, and over half of the cell membranes are made out of saturated fats.
  2. Fats play a role in regulating enzymes by controlling if an enzyme can reach a receptor site or not. If the membrane is made out of a certain type of fat, the receptor site can be hidden, while if it is made out of another, it can be available for use.
  3. Fats are necessary for managing inflammation. If the omega 3/6 fatty acids are consumed in inappropriate quantities, this can throw off the body’s natural way of managing inflammation.
  4. The essential fatty acids linoleic acid and alpha linolenic acid cannot be made inside the body and must be supplied by the diet. They are precursors to local messengers called prostaglandins and important for cell membranes and structure.
  5. Cholesterol is the raw material that hormones are made out of. It is used in the skin cells to make the precursor to vitamin D, and also is used for the production of the precursor to the steroid hormones (stress and sex hormones).
  6. Fats are necessary to transport and absorb the fat-soluble vitamins A, D, E, and K. Without sufficient fat in the diet, these incredibly essential nutrients cannot be absorbed.
  7. Fat slows gastric emptying, increasing the hormones that make us feel satiated.
  8. Fat cushions our organs, bones and joints as well as provides a source of energy.

Amazing, isn’t it? They don’t tell you that when you sign up for a low-fat, vegan diet! Turns out fat is incredibly essential and useful in the body. After coming to this conclusion and doing some more research, I came across the information that it takes about 7-10 years for the body to replace most of its cells. Some cells never get replaced (neural cells), and others get replaced very quickly (skin cells). It turns out that most cells have a life of a few years. After finding that out, I was mortified to think what my structure was made out of after eating vegan for a decade. During that time I abstained from all cholesterol, and I didn’t eat any saturated fat besides what was found in nuts. I didn’t take supplements like fish oil or vitamin D. The fat in my diet was primarily from nuts and highly processed seed oils – canola, grapeseed, soybean, and safflower. I regularly used butter substitutes like earth balance. I ate tons of omega 6 oils and no omega 3s. No wonder my skin was increasingly thin and flaky, my joints hurt, I had problems with chronic pain, I never felt satiated, and my hormones were in the tank.

It has been a little over a year and I am beginning to see improvement in my fatty-acid status. My skin is no longer thin, rough, dry or flaky. This did not begin to change immediately, but around 6 months after I started eating fat again I noticed the beginnings of change, and it still gets better with every passing month. My chronic pain has greatly reduced, and my pain during menstruation has almost completely gone away (I believe this is related to eating a proper balance of omega 3/6 to manage the balance of prostaglandins). I am still having some issues finding hormonal balance, but knowing that my body now has the materials to make them has me hoping for the best. I am committed to giving my body quality fats to heal from my past abuse as a vegan, even if it might be years before I fully feel the effects of it.

In my next article in the series I am going to provide a little guide to healthy fats.

Have you ever been on a low-fat diet and change to a more nourishing one? What types of changes did you notice and how long did they take?

About Mickey Trescott

Mickey Trescott is a co-founder here at Autoimmune Wellness and a co-teacher of AIP Certified Coach. After recovering from her own struggle with both Celiac and Hashimoto’s disease, adrenal fatigue, and multiple vitamin deficiencies, Mickey started to write about her experience to share with others and help them realize they are not alone in their struggles. She has a Master's degree in Human Nutrition and Functional Nutrition, and is the author of three best-selling books--The Autoimmune Paleo Cookbook, The Autoimmune Wellness Handbook, and The Nutrient-Dense Kitchen. You can watch her AIP cooking demos by following her on Instagram.


  • Kat says

    I am glad to see you’re back! The new website looks great. I also recently switched from a low fat diet, and it has been hard to get used to eating so much fat. Now I have come to realize that eating fat is the only way to get satiated. I used to eat carbs all day long when I was vegetarian, and now I can easily eat three meals a day with no snacking. The information you’ve given us really makes sense after what I’ve experienced.


    • autoimmunepaleo says

      Thanks Kat! That has been my experience as well 🙂

  • Eileen says

    Very well written and such important information. People are always asking me about this, and sometimes it’s hard to explain it clearly. I’ll now forward them a link to this page. I wasn’t vegan, but I was on a low-fat diet for years leading up to my autoimmune onset. I don’t think it was a coincidence either. I was calorie counting to lose weight, and since I didn’t want to give up my bread and cookies, I gave up oils and butter. Not a good trade. For the first few months on Gaps/Paleo, it was so weird to slather on large quantities of healthy fats. I was squeezing them in anywhere I could, because Dr. Natasha Campbell-McBride (author of the Gaps Diet) said that the more fat you eat, the faster you’ll heal. I took that to heart, because I wanted to feel better as quickly as possible! Some days, I would even swallow coconut oil like a vitamin (not recommended, by the way. It’s much tastier in food). So, I can relate to your before and after experience. It’s interesting that the China Study gets so much play when the science behind it has been thoroughly debunked. That’s another link I share frequently (rawfoodsos’ critique.) By the way, did you know that two famous vegans recently “came out” to their tribe that they’ve switched to eating meat for their health? Kristen Suzanne & Alexandra Jamieson. If you do a google search, they both wrote some pretty powerful blog posts about it. By the way, I’m so glad you took a break and have regained your energy. I love your blog, and I missed you, but I think what you did is excellent role modeling, too.

    • autoimmunepaleo says

      Thanks for the comment Eileen! I love Denise’s work and it was very important in helping me change my views that veganism and vegetarianism were healthy. I also read those bloggers accounts – really brave of them to put that out there! When I was getting ready to make the switch, I was scouring the web for that shred of information that someone figured out how to heal themselves with autoimmunity on a vegan diet so that I wouldn’t have to change. What I found was an overwhelming amount of information to the contrary, mostly stories about vegans that were way more ill than I was or those who changed their diets and felt a million times better. It was eye opening, to say the least. 🙂

  • […] In my last article I gave a little personal background on my decade of low-fat vegan dieting and how I believe it contributed to my ill-health, as well as gave you a bunch of reasons why fat is incredibly necessary for the optimal functioning of the human body. Here I have prepared a little guide on fats, as they apply to someone on the autoimmune protocol. […]

  • Grant says

    Great blog and great article, my own experiences dealing with auto-immunity are similar. I tried Vegetarianism but crashed so bad that I spent the better part of the next couple months in bed.

    • autoimmunepaleo says

      Thanks! Vegetarianism didn’t work out for me, unfortunately it took me 10 years to figure that one out. For now, I am trying to recover by eating loads of healthy fats… 🙂

  • Jussie says

    So glad I have stumbled on your blog! My story is very much like yours as I was diagnosed with Hashi’s and celiac, I was also a vegetarian from age 11 and a vegan for 2 years! I now eat meat and my results have never been better in 15yrs!! I am currently really battling with the moral issue of eating meat and wondered if you had any tips for not beating yourself up about it? Thank you in advance.

    • autoimmunepaleo says

      I have been planning some blog posts on the topic in the future – the short story is that it has been hard to wrap my mind around eating animals, but I can’t argue with the way I feel when I include them in my diet. I am no longer able to suffer so that an animal doesn’t, but that doesn’t mean that I will eat conventionally raised meat or anything like that. I am committed to doing my best to source meat from people who raise them ethically, and most of the time that means not buying from the store and sourcing from local farms instead. I will expand on this at some point. Much luck to you!

    • Katherine says

      Jussie, I too struggle with the issues surrounding eating animals. Like Mickey, I do my very best to insure that the animals I eat are raised in humane, biologically appropriate ways which means generally meants eating locally produced meat from pasture-centered farms. Additionally, I (mostly) choose beef over chicken because the meat, bones and organs from a cow can feed my family for a long, long time whereas a chicken can feed my family for about a day. The added benefit is that ruminant meat is generally more nutritious than poultry — it’s a double win!

      I don’t have the emotional discomfort with fish consumption but rather environmental concern so I’m careful to purchase fish that is sourced sustainably.

      Additionally, we eat the minimum amount of animals and animal products necessary for health and do not take the biological imperative to eat of animals as free license to eat as much of them as possible.

      I also incorporate bivalves into my diet as they’re very, very nourishing (clams, iron; oysters, zinc) and have no CNS and therefor do not feel pain. They also tend to be farmed in environmentally sustainable ways.

  • annakay says

    Jussie please a great book by Liere Keith called “The Vegetarian Myth”.

  • Barb says

    Only just found this entry and your BLOG as I also have been a vegetarian for so long that these blogs didn’t catch my attention. When an auto immune disease struck I went the whole way and explored vegan – although butter was my downfall there and even tried raw( all the best organic I could find) in an attempt to heal myself – I was, and still am, convinced that diet will do it. My issues all came to a head when I then developed a severe intolerance to salicylates – and therefore most of the vegetables and fruits which “sustained” me. I lost so much weight that I had to turn to meat and fats just to keep going. I still haven’t come at organ meats and chicken and fish is also a real challenge but I am coping with good grass fed lamb and beef and now reading all the Paleo books and blogs while I sip my bone broth. I am fermenting things – still not really enjoying, but it’s amazing what we will do for our health and I am determined to put the autoimmune condition into remission and overcome the salicylate intolerance.

  • Ian says

    Thanks for this great article, I can relate with this. I did the same for 13 years with vegan and raw vegan approach only to find myself with severe mood disorders and inflammation.

    Now I’m actually starting to have days where I know what it means to really be alive, thrive and feel confident and grounded!

    Cheers to BACON and animal fats!

  • Ellen says

    Hi everyone, so I love all this info, and I totally get it about what our bodies need fats for, but YET I am still worried that my cholesterol & LDL is going to go up and my mainstream-MD is going to flip out and tell me that I need to eat less animal meat & fat. How can I combat this fear? Is this a realistic concern? Do I need to get my lipids checked more regularly now?



  • […] Vitamins: Chard is also a rich source of vitamin A, vitamin C, magnesium and manganese. Since vitamins A and K are fat-soluble vitamins, be sure to cook your chard with plenty of healthy fats, to help you absorb these valuable nutrients. […]

  • Lori says

    Love this post! People often ask me questions related to fat and cholesterol and this is a great summarization: easy for everyone to understand. I will have to share your link on my blog’s Facebook page. Thanks for sharing!


  • Frankie says

    I have been on an anti-inflammatory diet before which recommends no animal products/fats because animal fat increases the arachidonic acid cascade (pro-inflammatory). How does one explain how eating bacon (high fat) not increase inflammation? It seems counter-intuitive to me?
    Thank you.

    • Mickey says

      Hi Frankie, you bring up a good point. It is true that saturated fat fuels the AA cascade, which promotes inflammation. Having said that, I think this explanation is oversimplified, since all inflammation is not bad–its how our tissues are able to repair themselves. What is necessary is a proper balance of fats, especially omega 3 and 6, which create pro and anti-inflammatory prostaglandins. Animals that have been raised on their ideal pasture, i.e. grass for cows, have a more natural balance of omega 3 and 6. Conventional meat has much more omega 6. Chris Kresser answers this question on his blog in this article:


      Personally, I was on a low-fat, vegan diet for over a decade and I have never been so inflamed. Just my experience, but the way I eat that best manages inflammation is natural, whole foods, including plenty of properly raised or wild meats, and including things like bone broth and organ meats.


  • bart says

    I am visiting Europe and they use rapeseed oil for cooking here.
    It has only 2.7g of poly saturated fats per 10g. Is this oil safe?

    • Mickey Trescott says

      Hi Bart,
      Rapeseed oil is from a seed and not compliant with the autoimmune protocol. I would use some of the solid fats (coconut oil, lard, tallow) for cooking!

  • […] of this is true, and it takes some adjusting (read this article for a ranking of meat quality, this article on why good fats are your friend, and this one for an argument against grains for Autoimmuners). […]

  • […] invest in at least one high-quality fat for cooking as well as one for dressing salads, minimum. See this article for a discussion on fats, and this one for a guide on which to […]

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