Do High-Fat Diets Cause Depression?

Psychiatrist worked up about high-fat diets and depression study

Fat-Phobia Strikes Again

Earlier this month, the following headline showed up in my inbox:


It was distributed by Medscape (a widely-read e-news source geared towards medical professionals), as well as a variety of other media outlets, including Science Daily.

The study itself 1) was published in the British Journal of Pharmacology and is entitled High fat diet-induced metabolic disorders impairs serotonergic function and anxiety-like behaviours in mice. 

We have been (wrongly) told for decades by public health officials that dietary fat is unhealthy, so we tend to take articles that support this belief at face value, without question.

But before you clear your cupboards of all fatty foods, hoping for eternal happiness and tranquility, let me tell you why the results of this MOUSE study need not cause you any additional depression and anxiety.
SodaStream (Soda-Club) USA

Of Mice and Mental Health

Researchers fed one group of mice a low-fat chow and another group a high-fat chow. After twelve weeks, the mice eating high-fat chow had gained more weight. They had also developed high blood sugars, high insulin levels, and glucose intolerance. Sixteen weeks into the study, these mice also showed more signs of emotional distress.

Poor meeces.

Furthermore, when the high-fat mouse group was treated with the antidepressant Escitalopram (brand name Lexapro), the antidepressant failed to work.

The study’s authors concluded that high-fat diets may lead to type 2 diabetes, and that type 2 diabetes may then lead to depression and anxiety symptoms which respond poorly to antidepressants.


As a psychiatrist with a special interest in nutrition, I understand how important dietary fat is to the health of the brain, and I know that fat doesn’t cause type 2 diabetes. So, I took a peek behind the headlines to see if this study would confirm or challenge my beliefs.

What I discovered is that the researchers who conducted this study THINK their experiment is about fat, when in reality, it’s about SUGAR.

The proof is in the chow, my friends.

Show Me The Chow

I hunted down the ingredients and macronutrient composition for each of the mouse chows used in the experiment:

Low-fat chow main ingredients (STDA04, SAFE diets): barley, wheat, corn, soja meal, wheat bran, and hydrolyzed fish protein. Macronutrient composition: 43.5% starch, 16.1% protein, 3.9% fiber, 3.2% sugars, 3.1% fat and 2,791 kcal/kg.

High-fat chow main ingredients (D12451, Research Diets): casein, lard, sucrose, maltodextrin, corn starch, cellulose, and soybean oil. Macronutrient composition: 41% carbohydrate, 24% protein, 24% fat, and 4,730 kcal/kg. The carbohydrate in this chow consists of 21% corn starch, 29% maltodextrin, and 50% sucrose!!! Are you rolling your human eyes at these mouse researchers yet?

Yes, the high-fat chow was indeed higher in fat than the control chow (24% vs 3%), I’ll grant you that. However, it also contained 50% more protein, 70% more calories, and THIRTEEN TIMES the amount of refined carbohydrate, HALF of which was pure sugar! The control chow contained only 3% sugar and no refined starches at all.

But wait, there’s more.

The manufacturer of the high-fat chow, Research Diets Inc, makes a low-fat chow that it specifically instructs researchers to use as a well-matched control, yet this was not done. Here is a direct quote from the high-fat chow manufacturer’s product information sheet:

“We recommend that you use a matched, purified ingredient diet and not a grain-based ‘chow’ diet. There are many, many differences between purified diets and chow diets and these variables make it difficult to interpret your data from a study in which one group was fed a purified ingredient high-fat and the other a low-fat chow diet. Differences between your groups could be due to the level of fat, but could also be due to differences in fiber type and level, source of carbohydrate, and the presence or absence of plant chemicals (such as phytoestrogens), just to name a few.”

Instead of doing as they were told, the researchers went rogue. They used chows made by two different manufacturers, so their ingredients were almost completely different.

The protein in the high-fat chow was casein (milk protein), whereas the low-fat chow contained soy and fish proteins. The high-fat chow contained two kinds of fat: lard and soybean oil. The low-fat chow, made of whole grains, soy meal and fish protein, is FAR healthier in general for a mouse than the high-fat chow, which is essentially the mouse version of a really bad ice cream cone, loaded with highly processed ingredients.

With so many variables, how are we to know which differences were responsible for the results?

mouse with ice cream cone—what diet component is the culprit?

Don’t Be Fooled

Please think twice (or maybe even a few hundred times) before taking this fat-phobic headline seriously. High-fat diets do not cause diabetes. High-SUGAR diets (whether they are high-fat or low-fat) can, and frequently do. This poorly-conducted mouse study, if it tells us anything at all, simply confirms that well-established connection. To see the evidence for yourself, please read my post Why Sugar is Bad For You: A Summary of the Research.

Maybe this sorry study is trying to tell us that mice who eat too much sugar, dairy, and refined starches not only develop type 2 diabetes, but that they get depressed and anxious as well. Now THAT would be a potentially very interesting result, with profound implications for mouse psychiatrists worldwide.

High-Fat Diets and Depression

So, what about the role of fat in depression and anxiety disorders? When it comes to brain conditions, high-fat, low-sugar diets are GOOD. While there is very little scientific research available to tell us whether a high-fat diet could be helpful in treating depression, it is well-established that ketogenic diets, which are very high in fat, have uniquely powerful healing properties when it comes to other serious brain conditions such as epilepsy and neurodegenerative diseases. Time will tell if depression will be counted among them. [For more information, please see my post about ketogenic diets and bipolar disorder].

There is, however, excellent science demonstrating a clear connection between high-sugar diets and anxiety—in humans. More about that in a new post coming up later this season…sign up below if you’d like to be notified when it becomes available.

[To learn more about the history, politics, and science of the dietary fat myth which continues to inspire so much bad research, I highly recommend Nina Teicholz’s book The Big Fat Surprise and Gary Taubes’ book Good Calories, Bad Calories.]

Until then, question the headlines! It is very common to see proclamations that high-fat diets cause disease, death, and worldwide destruction, but every anti-fat study I’ve ever read failed to take the amount and quality of carbohydrate in the diet into consideration. I know of no properly conducted study demonstrating a connection between whole-food sources of fat and human disease.

The single most important thing you can do for your health is to replace the bad carbohydrates (sugars and refined starches) in your diet with healthy fats!

Don’t let your good health be destroyed by bad information.

Sign up to be notified of my latest posts!

Signup now and receive an email once I publish new content.

I will never give away, trade or sell your name or email address. You can unsubscribe at any time.

Tagged with:


References   [ + ]

Tagged with:
  • Mark

    This will never end. Bad science. Bold headlines. A generally overweight, sick population upset that even though they followed the “expert nutritional guidelines” (sometimes for many years) they still feel bad and die younger than they should. Thank you for being there to set things straight.

    • Dear Mark,

      At your service! Love the way you summarized these important issues in your comment. Bad science, bold headlines, indeed.

  • Morgana

    My guess is that the researchers *knew* what they were doing when they set up that diet, and what result they wanted to get. Typical…(rolling eyes). I used to eat a high carbohydrate, low fat diet, as recommended, and had major issues with anxiety and depression (among other problems). Since I reduced carbohydrate and added much more fat, I don’t get depressed like I used to. So that is my own N=1; I don’t need a rodent study to tell me the truth.

    • Hi Morgana

      The same is true for me! My mood is so much better eating this way than it used to be years ago. N=2 🙂 As for whether the researchers deliberately manipulated the chow to get the results they wanted, I’d like to give them the benefit of the doubt and hope that they simply didn’t scrutinize or think much about the chow ingredients. I guess that’s the best case scenario, anyway. I hope they didn’t, but I have no way of knowing.

  • We get “DEBUNK THIS, BITCHES!” kinda stuff like this all the time on the keto/science boards, so wearisome.

  • Wendy Allen

    Saturated/monounsaturated fat hurts me..clogs my blood vessels. Good fat like fish oil/evening primrose oil/phosphatidylserine/DMAE, Lecithin, krill oil, CLA may help and raw walnuts (open shells to avoid hidden gluten and freeze so fresh). Depression can be due to low oxygen in the brain due to eating gluten/dairy/soy/sugar/GMO. Not eating these and taking vitamins/good oils/minerals..probiotic..LDN..detoxing may help and more like rhodiola/coenyzme Q10, coenyzmated B vitamins, MTHF, Amour thyroid if needed, Vit B12 methylcobalamin shot/under the tongue kind etc., HCl and enzymes with meals, dairy free probiotic when stomach acid is low, Mg, Zinc, Vit D3 5000IU, Vit C and more may help the brain/body/rebuild cells to burn oxygen. Antibiotics may hurt mitochondria and lower oxygen in the brain. Chemicals/heavy metals may hurt. Far Infrared Sauna may help detox chemicals/heavy metals/yeast/Lyme etc. Good water/sunlight/exercise/organic food/cooking own food..not eating food with a label which may have hidden gluten may help. Nuts not sold in the shell/meat basting/some spices/food in a box/label/certified gluten free food may have 20ppm of gluten which may hurt. Raising oxygen in the brain may help depression/anxiety/obsessing/no sleep/panic/suicidal thoughts and more. Best wishes.

    • Mark

      “Depression can be due to low oxygen in the brain …”

      “Raising oxygen in the brain may help depression/anxiety/obsessing/no sleep/panic/suicidal thoughts and more.”

      Would love to see cites on these statements!

      • Wendy Allen

        You may not find studies on everything that helps depression.

        Raising oxygen in the brain /body may help depression/anxiety/obsessing/no sleep/panic/suicidal thoughts by:

        —- thyroid medicine if needed and Zinc/Se/enough iron/probiotic to help convert T4 to T3 or more iodine/iodide/no soy which blocks thyroid

        —no gluten and LDN which blocks hidden gluten so more nurtrients absorb in intestines and multiple vitamins like Nature’s plus- Source of life/protein so cells are made right to work right and burn oxygen….

        —unclogging blood vessels EDTA or Serrapeptase may help and saturated/monounsaturated fat may hurt….

        —increasing circulation by Vit C/Vit E/ginkgo/MTHF/fish oil thins the blood

        —Raising oxygen by Vit B12 methylcobalamin shot/under the tongue kind.

        —Detoxing with Far Infrared Sauna or EDTA/DMPS IV chelations or organic sulfur or Now brand- Detox support or Vit C and glutathione and more may help raise oxygen.

        —Good water/exercise/organic food may help circulation and lower heavy metals which can block thyroid.

        —Raising oxygen by helping mitochondria burn …coenyzme Q10 is the spark plug for the mitochondria

        —-Good oils which help the brain/body work better….2000mg fish oil , 20000mg evening primrose oil. 2000 mg lecithin, Phosphatidylserine/DMAE, krill oil, CLA

        — Vit D3 5000IU or sunlight which helps stop autoimmune attacks on the intestines and thyroid and may stop crying or no reason.

        —Mg helps 350 chemical reaction and Zinc 50 chemical reactions

        — Lowering inflammation and swelling..No gluten/dairy/soy/sugar/GMO….Fish oil lowers inflammation.

        —balance Th1 and Th2. Too much Th2 foods may cause swelling.

        —Coenzymated B vitamins so they work better to raise oxygen than synthetic kind of B vitamins. Benfotiamine is fat soluble Vit B1 which can go into the brain and help raise oxygen. It may help obsessing fast.

        —PTSD can be due to burned out adrenals. Adrenals formulas on Amazon or LDN or rhodiola or licorice or cortisol may help and the rest of the things I list.

        —Rhodiola and other herbs that may help raise oxygen.

        —Sleep….Vit B12 methylcobalamin shot or under the tongue kind/cream/spray/intrinsic factor kind with MTHF and cortisol tiny amount daily may help if needed and Celiac diet etc I mentioned.

        —Panic…is due to low oxygen in the brain and all the ways I mentioned here may help and rhodiola/detoxing/100% no gluten etc.

        —No antidepression drugs which may have F which blocks thyroid and has many side effects. LDN may help block hidden gluten and help heal the gut lining and lower inflammation and help liver deox and much more…is like a miracle to help. Hidden gluten maybe in food with a label or certified gluten free or nuts not sold in the shell/meat basting or some spices etc. Microscopic gluten may hurt.

        —Antibiotics may hurt the gut lining/lower the immune system/hurt the brain/body and mitochondria lowering oxygen.

        —Herbals may help infections and only help the brain body like garlic which may help thyroid with Se and lower cholesterol and with S help detox etc.

    • twitchyfirefly

      “Saturated/monounsaturated fat hurts me..clogs my blood vessels.”

      I’m curious what exactly that feels like.

      • Wendy Allen

        It is like no circulation in the area/dead feeling in the area where I rubbed the coconut oil on my face. Blood vessels clogged is like blood is slower and sputtered in my brain. EDTA/DMPS IV chelations helped and Taurine helped, but best was not to eat them…too much suffering/pain. Food trials….I eat the same food and change only one food…then I can tell what is happening with the new food. For example: Gluten…I stopped it for 2 weeks and ate it again…I felt like I was dying. Two weeks of no gluten..felt 20 years younger and 1000X more energy. I eat meat once a year and notice how it feels. I ate one burger at a facebook place and within 2 bites my blood vessels were already clogged. It is hard to describe…like a numbness. Coconut oil clogging my blood vessels made spider veins in my leg.

    • Joris

      Dude if you need SO MUCH supplements to aid a little with your depression, then your “no saturated fat” diet is probably reponsible for this. And no saturated fat don’t clog arteries : there s a shitload of reaserch debunking this one. Stop repeating gov bullshit and use your brain before it totally become useless.

      • Wendy Allen

        Saturated fat clogging blood vessels means it is not being used properly and is not helping the brain. MS people get hurt by saturated fat. Fish oil hurt me also when my thyroid was low. My body is going too slow to use the fat. Olive oil hurts me also. I take many good oils which do not hurt me. Fish oil/evening primrose oil/lecithin/phosphatidylserine/DMAE/CLA/raw walnuts (open the shells to avoid hidden gluten)/poached cage free antibiotic free organic eggs. I can’t eat meat…hurts me/clogs blood vessels. Yes..glands/brain/cell membranes need oil, but I have to use the oils that only help and don’t hurt.

        Depression/anxiety/no sleep/obsessing/panic/suicidal thoughts …just rebuild the cells to burn oxygen. Low oxygen in the brain can cause depression. Gluten may hurt the gut lining so less nutrients/oils/vitamins etc absorb and then cells are not made right to work right. Antipression medicine may have Fluorine that blocks thyroid/lowering oxygen causing more depression/suicidal thoughts.

        Gluten is wheat/barley/rye/corn/oats/rice. I still eat rice, but take LDN/gluten enzyme to block the small amount of gluten. I can’t have coconut oil/olive oil/turmeric/resveratol etc…things other people can have. Each person is different. They need to figure out what foods help/hurt and what supplements may help if needed. Saturated fat clogs my blood vessels. They will eventually come out and say it is not good for all people. A few Alternative doctors/chiropractors have recently died of heart attacks. Maybe the saturated fat hurt them. They used to say don’t eat eggs, but they help me. You have to listen to your own body..not just what is in articles. Research maybe bias and not always accurate.

  • paleopete

    From my perspective, for what its worth, there is a real and genuine “pushback” from the conventional camps from the ever growing body of scientific studies which are basically saying the conventional wisdom is/was patently wrong.

    • Well said, PaleoPete. Hopefully it’s the last wave of protest before the long-overdue death of the low-fat paradigm.

  • Emaho

    Dr. Ede thanks for the great article. It is great because of the science discussion and also the humor. Have you ever thought about doing a comedy routine? Maybe you could team up with Gaffigan. His routine on bacon is one of my favorite:

    • Hi Emaho

      Thanks for liking my sense of humor and thanks especially for the video–it is hilarious! I personally find reading about mouse experiments to be inherently entertaining, but I’m pretty sure I’m alone on that one, so I try to spice the research posts up with some humor so that people have a shot at making it all the way through to the end! Thanks for reading and for adding to the fun:)

  • John J

    Thanks for your sane approach to good science, Dr. Ede! I think I ate that bad so-called ‘high fat’ chow (human version) for years, which is why my metabolism is so messed up! But I’ll carry on with my corrective plan of minimal digestible carbs, sufficient high-quality proteins, and healthy whole fats to keep hunger at bay. It seems to be the only way to reverse metabolic syndrome, along with exercise. Thanks for your blog, much appreciated.

    • Hi John

      Thank you; as a psychiatrist, sanity is my specialty:) Stay the course with your excellent plan. Love the human chow analogy! I am picturing you peeling out of your driveway, throwing your old human chow pellets out the window, and waving goodbye to them in the rear-view mirror as they bounce on the asphalt behind your car. Just hope no poor unsuspecting mouse happens upon them…

  • Matthew Ricci

    Hi Dr. Ede, just read your blog and was very glad to see that you did what journal reviewers should have done – looked at the mismatched diets and noticed that they were completely inappropriate for comparison to each other. This, as you point out, is a big problem in animal diet-induced disease research that will only go away with more education. Thanks for pointing this out.

    • Dear Dr. Ricci

      Thank you so much for reading my post and weighing in. As an experienced scientist who works in the field of animal-based diet research, your opinion means a lot. I hope that researchers will begin to pay attention to manufacturer’s recommendations and YES, that journal reviewers will take the time to examine the diets used to ensure that proper controls are in place!

      For those who don’t know Dr. Ricci, he is the science director for Research Diets; he spoke intelligently about the problem of improperly-controlled animal diet studies in this excellent piece published on Nov 23rd in The Scientist entitled “Inside a Lab Mouse’s High-Fat Diet”:

  • E.G.

    I’ll say it again: “I love you Dr. Ede.” 🙂

  • Marco

    OT: You mentioned organs are healthy to eat. Does this extend to Pate etc.? I actually live in China so not that hard to find organs/offal, usually lung, liver, kidney, heart, tripe, tounge and in some places insects which are actually not so bad.

    I have spent time in Mongolia for business and all they eat is basically meat with alot of fatty cuts. Their babies grow very quickly and at 1 year is about twice the size of a Chinese baby from what I have seen, the cold probably impacts this aswell. Interested I checked IQ ranking and found Mongolia is ranked 6th highest in the world… pretty good for a population that is still or only recently left a nomadic lifestyle… I think the diet plays a role in this.

    • Hi Marco

      Very interesting! Thank you for sharing your perspective from China! Yes, pate is made from liver, and liver contains many healthy nutrients, so pate can be very good for you. The only concern with pate is that it can sometimes contain other ingredients, such as dairy, which can bother some people with food sensitivities, but each recipe is different. Thanks for writing in!

  • bigmyc

    Hi, Georgia. Just wanna say that your blog and its comprehensive approach to all things diet is a real “heavy weight” among the blogs that I’ve come across in the nutrition-o-sphere. That was a boxing reference, btw.

    I really like how you are not afraid to challenge convention..or even, the newer conventions. I will be adding yours to my daily/weekly reading list. Keep up the great work.

    • Hi bigmyc,

      Thank you so much for your very kind words! I’m glad you find the work useful! I’ll continue to try to provide information that you find valuable.

  • Malaena Medford

    Hey, there,

    Came across your work and I hope you don’t mind me referencing your blog on my own nutritional blog along with a few things included in your own research. Trying to get people to understand how to read science is like herding cats. I had one doof complain that I only got my research from NIH one time…and they failed miserably at comprehending when I told them NIH PubMed is JUST a catalog of published journals, and I even pointed to the bottom where all collaborative journals are locates with links to the original articles.

    I really enjoy your articles, and as a student nutritionist, they are really encouraging and contain links to much-needed informational documents with explanations on highly specific details.


  • Alyssa Finch

    Thanks you for using the term ‘brain conditions’; it very clearly puts mental illness in where it belongs, in the ILLNESS category, where it belongs. And thank you for this post! My husband and I just started a ketogenic diet (I’m training for a half marathon in two years and he’s in the Army and so needs to make weight) and I’ve been wondering if it hasn’t been effecting my depression (which has been all over the place) but having read this and a few other things I believe my other suspicion is more correct and that I just need to get my meds figured out (because you really needed to know all this 😂).