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Is Fat Bad and Can Low Fat Diets Cause Depression?

A reader wrote on Facebook that she was on a diet and was feeling depressed. Although she admits to losing weight, she felt that her mornings were no longer met with enthusiasm and wondered if it could be her new food choices.

She started a, what I call, “home-made diet,” mostly all salad. This reader completely eliminated all fats — even those found in nuts. She admits to drinking wine at night to “feel better.” I asked Dr. David Edelson, an Assistant Clinical Professor of Medicine at Albert Einstein College of Medicine and former director of the Weight Management Clinic at North Shore-LIJ Medical Center, if low fat diets can cause depression. Here’s what he advised:
Research seems to indicate that low fat diets can cause depression. A recent article in the British Journal of Nutrition followed 20 individuals on two diets, one with 40% of calories from fat and one that started with 40% fat and after one month, switched to a diet with only 25% calories from fat. The latter group showed a 25% increase in depression and hostility from baseline.

It seems logical that too low a fat intake can affect both normal hormone production (through lowered cholesterol intake) as well as possible nerve and cell membrane repair that comes from healthy fat sources.  Either of these could lead to the findings seen by these researchers.  Omega-3 fats are vital to our health, both physical and mental.

Is fat bad?

Dietary fat is essential for life.  Our bodies use fat to produce a huge variety of tissues and hormones including:

  • Cell membranes: virtually every cell in our body has an outer layer produced from phospholipids, a derivative of fat.  Without fat, the wall of the cell would collapse and the cell disintegrate.
  • Myelin (nerve) sheath:  the coating on nerve and brain tissue is composed of 80% fat. Without it, the nerves would not be able to talk to each other, and diseases such as Multiple Sclerosis develop.
  • Hormones: virtually every hormone produced in your body starts out from the cholesterol molecule.  The body uses this form of fat as the building block for estrogen, testosterone, cortisol, progesterone, and many other essential hormones required for normal body function.

What is the recommended daily allowance of fat?

This depends on the individual in question, as there is no single diet that works for every person. It also depends on the TYPE of fat being consumed.  Bad fats (saturated and trans-fats) should be kept to an absolute minimum (less than 5% of daily calories.)  But good fats (Omega-3′s, Mono-unsaturated fats) should be consumed with gusto, especially in individuals with diabetes, metabolic syndrome or any condition associated with insulin resistance. In these individuals we often increase healthy fat intake to 30-40% of daily caloric intake.

Dr. Edelson is the founder and medical director of HealthBridge, a nationally recognized preventive health facility. Dr. Edelson is widely recognized as one of the nation’s top weight loss experts. He is board certified in both Internal Medicine and Bariatric Medicine, and is a two-time recipient of the Faculty Teaching Award at North Shore/LIJ Medical Center. Dr. Edelson has been a featured speaker on Obesity Management for Medical Grand Rounds at some of the top hospitals in the country. He has published independent research in the Journal of the American Diabetes Association, Nutrition, and has been featured in articles in The New York Times, Woman’s Day, and Essence, among many others.


  • Thanks for posting this.

    There have been studies that link high levels of Omegas 6 & 9 and low levels of Omega 3 to violent behavior.

    Fat is not a bad word. Our brains need healthy fats and complex carbs to function properly.

    Not to mention low-fat diet foods are all highly processed and full of crap they use to replace the fat. Bad stuff.

    Saranna DeWylde

    1:50 pm

  • It really is amazing how fat has become a bad word in our beauty focused society. We need fat in our diet. I am glad you wrote this article.

    Simone Cruz

    10:28 pm

  • I think when we eliminate things that our bodies need, our bodies react. There are definitely good fats that are amazing for us. When our body is getting what is needed, we may be surprised at the way we feel!

    Gena Morris

    10:14 pm

  • I basically cut fat out of my diet from a very young age. I can eat very little amounts of fat, but too much makes me feel sick. I do have some low days, but I wouldn’t call it ‘depression’, but I never linked my moods with diet. think I should slowly start including more good fats in my diet. Maybe start with some olive oil.
    I have read that Omega 3 can actually help against depression.


    9:59 am

  • I think that every diet should have some fat in it. You just have to make the right food choices to avoid excess fat or unhealthy fats. I could eat avocados all day long, so that’s my fat of choice!


    8:37 am

  • Thanks Rona. Yes, it is important to not loosely use “depression” when we simply mean something less problematic


    2:24 am

  • No, it wasn’t sad, because ultimately mine’s been a story of triumph: As I said, I no longer have Clinical Depression. My point on both pages that while nutrition has been a major factor in my depression, my weight never has, it has only been a minor issue and irritant in comparison to the issues that depressed me.


    2:15 am

  • What is being said on your Facebook page is really important and useful to people who suffer from depression. What Nicole commented is very sad.

    Rona E

    1:48 am

  • I went thru the same thing but mine included rage. There were time that I would get so upset for no reason. It kinda scared me.


    1:30 am

  • Well, I CAN eat liver, but it’s got to be covered in onions, eggs, and ketchup. The dietary results are WELL worth it for me; I seem to be VERY sensitive to malnutrition.


    1:20 am

  • When we were kids, my mom would cook liver and I. just. could. not. eat. it. That tough, fiber string thing that seemed to always appear in the middle of the meat. Revolting, to this day.

    Stefan Pinto

    1:16 am

  • My own experience with Clinical Depression bears that out: When I eat super-healthy foods like liver, which of course has fat, I feel MUCH better for days on end.


    1:07 am

  • Sounds like she might just be hungry?

    Adam Kastoria

    12:12 am

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