7 Ways The Low-Fat Diet Destroys Your Health

Unhappy Woman Holding a VegetableIn the beginning, the conventional low-fat diet was based on very weak scientific evidence, which has since been thoroughly disproven.

In the past few decades, many massive, long-term studies have shown that this diet is a very poor choice.

Not only is it proven to be ineffective, it can also be downright harmful for a lot of people.

Here are 7 ways the low-fat diet can harm your health.

1. The Low-Fat Diet Encourages Consumption of Harmful Foods

When the low-fat guidelines first came out, food manufacturers jumped on the bandwagon.

They wanted to bring a whole bunch of “heart healthy” low-fat foods to the market, in order to sell to the health conscious crowd.

However, there is one big problem with foods that have had the fat removed from them… they taste like crap.

For this reason, the food manufacturers added sugar instead. Sugar is not a fat, it’s a carbohydrate. Therefore, a product can be labelled “low fat” even though it is loaded with sugar.

(I should point out that the low-fat guidelines DO recommend that we reduce refined sugars, but not nearly as enthusiastically as they warn us about the “dangerous” fats).

The conventional low-fat diet (brought to you by the United States Department of Agriculture) also advocates increased consumption of certain foods:

  • Vegetable Oils: Vegetable oils can reduce cholesterol in the short term, but in the long term they cause harm and are significantly associated with inflammation and heart disease (1, 2, 3, 4, 5).
  • Whole Wheat: A significant portion of the population may be sensitive to wheat gluten, experiencing symptoms like pain, stool inconsistency, tiredness, among various other symptoms (6, 7, 8, 9, 10).

Basically, since the low-fat guidelines came out, people have increased their consumption of harmful foods like sugar, wheat and vegetable oils.

Bottom Line: Many high sugar junk foods with a low-fat label have flooded the market. The low-fat diet also advocates consumption of foods now known to cause harm.

2. The Low-Fat Diet Can Raise Your Triglycerides

Bread Caution

Having elevated triglycerides in the blood is a well known risk factor for cardiovascular disease.

It is also one of the features of the metabolic syndrome, a cluster of symptoms believed to play a causal role in cardiovascular disease, obesity and type II diabetes.

When blood triglycerides are eleveted, it is usually because the liver is turning excess carbohydrates (especially fructose) into fat (11, 12, 13, 14).

Because the low-fat diet is also a high-carb diet, this diet can lead to an increase in blood triglycerides, potentially elevating the risk of cardiovascular disease (15, 16).

The best way to lower triglycerides is to eat in the exact opposite way, a low-carb, high-fat diet. Such a diet consistently leads to reductions in blood triglycerides (17, 18, 19).

Bottom Line: The low-fat diet is very high in carbohydrates. Excess carbohydrates are turned into fats in the liver, which raise blood levels of triglycerides, an important cardiovascular risk factor.

3. The Low-Fat Diet Discourages Consumption of Healthy Foods

Chicken and Egg, Smaller

Animal foods that are naturally high in fat tend to be healthy and nutritious.

While I agree that factory farmed, grain-fed animal products aren’t an optimal choice, foods from animals that have been properly raised and fed are very healthy.

The low-fat diet discourages people from consuming these foods because they contain saturated fat and cholesterol.

Here’s a newsflash: Neither saturated fat or cholesterol have ever been proven to cause harm.

It was a myth all along, they have now been proven to be perfectly safe in multiple large, long-term studies (20, 21, 22, 23).

Blaming the epidemics of obesity, diabetes or heart disease on fatty animal foods makes absolutely no sense, because the diseases are relatively new, while the foods have been with us all along.

Plenty of populations throughout the world, for example the Inuit and the Masai, have consumed almost all of their calories from animal foods and remained in excellent health.

Here are 4 examples of foods that have been demonized due to the misguided war on saturated fat:

  • Meat: Naturally fed meat is an excellent source of Omega-3 fatty acids, CLA, vitamins and minerals along with important nutrients like Carnosine and Creatine (24, 25, 26).
  • Eggs: Eggs are among the healthiest foods on the planet. They are loaded with vitamins and minerals, along with Choline and powerful antioxidants that protect the eyes (27, 28).
  • High-fat dairy products: Grass-fed dairy products are the best source of Vitamin K2 in the diet. Also loaded with Calcium, CLA and plenty of other nutrients (29, 30, 31).
  • Coconut: Coconut products contain fats that are associated with powerful health benefits, including increased fat burning, better blood lipids and improved brain function (32, 33, 34).

Bottom Line: Foods that are naturally high in saturated fat and cholesterol tend to be highly nutritious and perfectly healthy. The low-fat diet discourages consumption of these foods.

4. The Low-Fat Diet Can Lower HDL (The “Good”) Cholesterol

Boy Eating a Sandwich

High Density Lipoprotein (HDL) is often referred to as the “good” cholesterol.

It is well established that having high levels of HDL is associated with a reduced risk of heart disease (35, 36).

Eating more fat can raise HDL levels, while a high carbohydrate intake can lead to a reduction (37, 38, 39).

Therefore, it is not surprising to see studies where a low-fat, high-carb diet leads to reductions in HDL, which may lead to an increased risk of heart disease (40, 41, 42).

One of many good ways to raise HDL levels is to eat a low-carb diet (43, 44).

Bottom Line: HDL is known as the “good” cholesterol and is associated with a reduced risk of heart disease. Studies show that the low-fat diet reduces blood levels of HDL.

5. The Low-Fat Diet Lowers Testosterone Levels

Unhappy Man

Testosterone is the main sex hormone in males, but women have small amounts of it too.

Like other steroid hormones, testosterone is produced out of cholesterol.

Having adequate testosterone levels is important for various aspects of health in both men and women.

Having low testosterone levels can lead to decreased muscle mass, increased body fat, osteoporosis, depression, decreased libido, among others.

One of the side effects of a low-fat diet is significantly reduced testosterone levels, one study showing a reduction of 12% after 8 weeks on a low-fat diet (45, 46).

Bottom Line: Testosterone is a very important hormone in both men and women. Low-fat diets can significantly reduce testosterone levels.

6. The Low-Fat Diet Can Harm The Pattern of LDL (The “Bad”) Cholesterol

Doctor Thumbs Down

Low-Density Lipoprotein (LDL) is often referred to as the “bad” cholesterol.

It is well established that elevated LDL levels are associated with an increased risk of cardiovascular disease (47).

However, new data is showing that there are subtypes of LDL. We have small, dense LDL (called pattern B) and Large LDL (called pattern A).

The small, dense particles (sdLDL) contribute to heart disease, NOT the large ones (48, 49, 50).

A high intake of carbohydrates (especially refined carbohydrates) increases sdLDL, while saturated fat and cholesterol change the LDL particles from the small, dense (bad) subtype to the large (benign) subtype (51, 52, 53).

Studies show that low-fat diets shift the LDL pattern towards small, dense particles, while low-carb, high-fat diets shift them towards large particles (54, 55, 56, 57).

Bottom Line: Even though low-fat diets may cause mild reductions in LDL cholesterol, at the same time they shift the pattern of LDL cholesterol from Large LDL (which is benign) towards small, dense LDL (which is very harmful).

7. The Low-Fat Diet Gives You Heart Disease

Old Man Taking Pills

Heart disease is the most common cause of death in middle- and high income countries (58).

It is known that traditional populations that don’t eat a Western diet have very little heart disease (59, 60, 61).

When these populations adopt a western diet, they rapidly become obese, diabetic and start dying from heart disease (62).

Therefore, it seems pretty clear that the western diet is a significant contributor.

There have been several massive, long-term randomized controlled trials (which are the gold standard of science) that have examined the effects of low-fat diets on the risk of heart disease.

  • The Women’s Health Initiative: In a study of 48,835 women, the low-fat diet produced weight loss of only 0.4 kg (1 lb) over a period of 7.5 years. The diet did not lower the risk of heart disease or cancer (63, 64, 65, 66).
  • MRFIT: A low-fat diet did not reduce heart disease in a group of 12,866 men at a high risk of having a heart attack, despite the fact that many of the men quit smoking (67).
  • Look AHEAD: A 9.6 year study of 5,145 diabetics revealed that the low-fat diet did not reduce heart disease, despite the fact that they managed to lose weight by forced calorie restriction (68, 69).

Be aware that they are comparing the low-fat diet to the standard western diet, which is pretty much as bad as a diet can get.

Another way to consider these results… The low-fat diet is just as effective at causing heart disease as the standard Western diet.

Take Home Message

It is time to retire the low-fat fad. Period.


  1. Alexander Rios says:

    You have a spelling mistake. Should be “elevated”.
    “When blood triglycerides are elaveted,”

  2. Spot on as usual Kris. Outstanding summary!

  3. So many people are misguided by this myth that low fat is good for you. Even my husband! We have been together now for 12 years and he knows I am a real foodie.

    But after months of not working out and eating what he wants (if I don’t cook for him it is Ramen noodles, mac and cheese or microwave popcorn or cereal or toast!) He has decided he needs to lose 15 lbs.

    He gave me two options: 1) he would lose weight by cooking for himself which meant a low fat, low calorie diet. or 2) he would eat whatever I gave him and then if he DOESNT lose weight, I would be responsible.

    Of course I got angry at him because I don’t want to be held responsible, so once that argument was over and solved, lol, I have enough faith in the high fat diet and low carb diet that I started him on it. In 1 week (today is the 9th day) he has lost 4 lbs so far.

    And he is pleased. I have been allowing him bread a few times a week, but only sprouted (like ezekiel or jack sprats) and no sugar of any type, but honey and stevia are ok. He can have potatoes once a week. Last week we split a potato for dinner with our chicken, and the next day we split another one, so he has had one potato a week, but since we are sharing it has allowed him more than one meal with a potato.

    I have been putting coconut oil in his coffee, with raw cream and stevia. Since he isn’t a breakfast eater I told him as long as he does the cream and coconut oil, (protein and fat) he can have that for breakfast.

    No cereal. Grassfed meats. I even fried some chicken nuggets (homemade, gluten free) in homemade grassfed beef tallow!

    And, I have made ice cream from raw cream, raw milk, raw honey, homemade vanilla, and he gets to eat that.

    He can’t figure out why he is losing weight.

    DOH!! :)

    • Mary Titus says:

      My, now ex, husband wanted to support me in my mission to lose weight through Atkins. All he did was give up beer and he lost 10 lbs…

    • Try oopsie rolls, you can google the recipe. I don’t put sweetener in them, some of the recipes call for it, but nobody seems to add it, lol. These have replaced bread completely for my family, they are life changing!! Lol my stubborn hubby even loves them, I add some spices to the yolk mix, garlic and pepper, sometime basil and rosemary, you use two rolls per sandwich, 1 carb each, can use for burgers, sandwiches… o.m.g..amazing!!

      Tips: let them sit 8+hrs before bagging and keep bag loose, sprinkling a little cheese on top before baking helps them not stick to the bags, can store in the fridge longer than on the counter and can be frozen! Also let eggs get room temp before whipping, and whip whites really stiff. I googled tips for making oopsie rolls and got some good tips! I make these every other day! Takes about 10-15 mins max!

    • @Rebecca: Your husband needs to quit acting like a toddler and grow up. Seriously.

  4. Another great summary and I especially like the “Take home message”. You rock, Kris!

  5. Hey Kris,

    I love the idea of your web page, unfortunately you are falling victim to a common mistake that people encounter when they write these types of “summary” articles.

    You have taken many of the referenced articles out of context, in an attempt to build support for your extreme arguments.

    I’m sure this was not done on purpose, but I encourage you to be more careful in the future, as you seem to have accumulated quite a following of people who consider you a credible resource for their nutritional information.

    Good luck in the future.


    • Thanks for the comment, but I disagree. We can all make mistakes though, can you name any specific examples so that I can have a closer look and perhaps clarify even further?

  6. Nice summary. Points 2, 4, and 6 are the same point restated. I’m not sure they should be discussed separately. Doing so has got us in this mess and has kept us here — statins for LDL alone. Sugars overwhelm our LDL pathways LDL size falls, HDL is last in line so it suffers, and oxidization pressure from glycation spirals out of control. The one cause, sugar, has multiple impacts. Occam’s Razor.

  7. I was on a low-fat diet prior to developing rheumatoid arthritis, and I don’t think it’s a coincidence. If our cell walls are made up of 50% fat, it’s no surprise I developed weakness bodywide and intestinal permeability that triggered an immune response.

  8. It’s nice to see Harvard researchers dedicating a page to busting the low fat myth. More research is now needed with regard to healthful fats.

    Gut microflora is essential to health. It plays a massive role- we now have learned this. There is so much more to be learned about the strains and specifics- and how our diets affects gut microbiota.

    MUCH uncertainty exists with regard to what really constitutes a healthful diet. We are all winging it. But, we have to eat in the meantime.

    People like Dr. Fuhrman are scamming the public. He admits to none of the overwhelmingly enormous uncertainties out there about human diet.

  9. Correct me if i’m wrong, but aren’t these all the same studies?


    Citations 64, 65, and 67.

  10. Hi Kris,

    Thanks for the articles and references. I thought maybe I could get your opinion since it’s hard to find well researched nutritional advice specifically for my situation.

    I am a relatively fit 36 year old male (5’8″, 150lbs, non smoker, bike 1 hour a day). I have metabolic disorder with a heavy dose of familial hypercholesterolemia. Left unchecked my total cholesterol count has peaked at 435 with an LDL count of 330. I’ve been on and off meds, mostly Lipitor, since I was 13.

    My mother died of a heart attack when she was 36. A year ago I got a coronary calcium scan with very poor results (score of 770). That, combined with the fact I have an 18 month old daughter with a 2nd on the way, really opened my eyes. It would be an understatement to say I’m taking this very seriously.

    Since the calcium scan I’ve been on Crestor and other meds. My diet, shaped by my situation and why I’m writing you here, is of the extremely low-fat variety. The documentary, Forks Over Knives, has been very influential for me. Fruits, vegetables, legumes (lots of soy products), fish, and rice and my mainstream diet. I don’t eat much sugar but I do eat a lot of wheat and other whole grains.

    Have you found information in your studies surrounding severe familial cases like mine? I get regular blood work done so I can do A/B testing to some extent, and I’d love to add back eggs and some other things, but I’d be interested in hearing what you had to say about it.

    Thanks very much.

    • Hello Andy. I really don’t know what would be the best approach in your case. I think statins and a low-fat diet can be useful in familial hypercholesterolemia.

      Not sure if a vegan diet with soy would be a good idea… there are other things than cholesterol that can exacerbate heart disease, like oxidative stress and inflammation. Maybe a low-fat version of paleo, with fruits, tubers, vegetables and some fish would be optimal.

      According to Dr. Chris Masterjohn (a very smart lipid researcher) this is a good idea, as well as optimizing thyroid function and make sure the rest of your body is functioning optimally (low inflammation is key).

      There are some discussions in this podcast and the comments (if you use find and look for “fh”): http://chriskresser.com/chris-masterjohn-on-cholesterol-and-heart-disease-part-3

      But other than that, I’m not sure. Definitely work with your doctor on this and I think in this case statin drugs can be useful. But these are just my opinions, haven’t really done much research on the subject.

  11. Jeremias Cuervo says:

    Actually, Esselstyn Jr. and Ornish already demonstrate in a small group, that a very low fat diet, is the best for your arteries. They were able to reverse the atherosclerosis in cardiac patients, and prevent them from happening. Esselstyn is finishing a study with 200 cardiac patients, and just one event in the group in years. This is 40 times better than standard treatment.

    This diet also normalizes blood pressure and type 2 diabetes.

    All the science about low fat diets, doesn’t count for the diet I’m talking about. Ornish demonstrated that a 12% fat, 20% fat, and 30% fat (the low fat recommendation) would have totally different effects on atherosclerosis. 12% will reverse, 20% will slow down a bit, and 30% is the key to a new heart attack.

    In my opinion, eating a food that preserves the health of your arteries is a pretty strong indicator you are eating what your body is expecting.

    I know low carb high fat, will make people lose weight, improve inflammation markers, but in fact there will be some atherosclerosis.

    Studies on flow-mediated dilation of the brachial artery show a single high fat meal is enough to impair the arteries for a few hours, while corn cereal does not. It’s important to differentiate sugar, processed carbs and sugars, from whole foods like potato, corn, and fruits. Once you are eating whole foods your organism will know what to do, without a problem.

    Why I am here, supporting this kind of diet?

    Because it was the only one that could bring down my blood pressure and my post-exercise hypoglycemia, in a few weeks. Low carb, high fat failed, in two months. I lost weight with both, but only the low fat plant based diet could cure it.

    Another pretty strong indication that it is a good diet.

    • “Esselstyn is finishing a study with 200 cardiac patients, and just one event in the group in years.”

      Do you have a link where I can read more about this study?

    • Great reply. I too am embarking on a “Plant Strong” diet, focused mostly on the Engine 2 Diet written by Dr. Esselstyn’s son, Rip. I am doing his 28 day challenge to go plant based. The studies he, and other doctors who follow his same way of thinking/eating have strongly shown that a plant based, whole foods diet is really key to optimum health, and ideally the way that human beings are supposed to eat, and are designed to eat.

      I think the key to understanding a vegan diet, is that vegan doesn’t necessarily imply healthy. Just because one doesn’t eat animal based fats, doesn’t mean they aren’t eating processed, unhealthy foods. I know a vegetarian who eats a lot of processed, unhealthy foods, they just won’t eat meat. The key is making it plant based, and whole foods based.

      You can still add healthy fats in there … like nuts, and avocados (although Dr. Esselstyn says stay away from that — his son Rip allows for it in his diet). Seeing actual reversal of heart disease is powerful.

      I would love to see someone take someone with heart disease, put them on a low carb, high fat diet, and see if they saw improvement in their heart health, to include blockages beginning to clear themselves up. I feel like the results wouldn’t come close to matching that of plant based nutrition.

  12. 200 people is a microscopic sized study group. I don’t think one can prove anything with a study of that size. I think a much better way is to look at countries that have a very low rate of CHD and see what they might be eating.

    Remember too, that all of the people in any study group will eventually die of something. Tiny study groups prove nothing, but they allow the doctors & dieticians to sell books, dvds, and speaking engagements.

    Somehow, their advice always comes down to the bottom line, more money in their pockets. I wouldn’t trust any of them, or their advice.

  13. Approximately 21% of Americans have Apo E4, a genetically-determined pattern. This means that the Apo E protein, normally responsible for liver uptake and disposal of lipoproteins (especially VLDL), is defective. In people with Apo E4, the higher the fat intake, the more LDL particles accumulate. People with Apo E4 drop LDL (and LDL particle number and apoprotein B) with reductions in fat intake.

    As with most things, genetic differences mean there isn’t one “right” diet for everyone. The trick is to learn what’s best for you. In my case, reducing dietary fat improved my cholesterol profile, reduced my CRP, and lowered my blood pressure. My testosterone is normal.

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