The benefits of replacing saturated fat with vegetable oils? Possibly none

Bottle of rapeseed oil (canola) and rape flowers bunch

The recommendation to replace saturated fat with vegetable oils is rebutted by a meta-analysis, which finds no clear benefits when it comes to heart disease risk:

Available evidence from adequately controlled randomised controlled trials suggest replacing SFA with mostly n-6 PUFA is unlikely to reduce CHD events, CHD mortality or total mortality. The suggestion of benefits reported in earlier meta-analyses is due to the inclusion of inadequately controlled trials. These findings have implications for current dietary recommendations.

The “implications” are that the current dietary recommendations to replace saturated fat with industrial seed oils are misguided and should be updated to reflect higher-quality science.

Nutrition Journal: The Effect of Replacing Saturated Fat with Mostly N-6 Polyunsaturated Fat on Coronary Heart Disease: a Meta-Analysis of Randomised Controlled Trials

The findings are not new, several meta-analyses have come to similar conclusions. One thing is quite interesting in this paper however. The only support for the idea that limiting saturated fats is beneficial comes from older uncontrolled trials, where other things in the diet were changed as well (e.g. less sugar). In controlled studies where the only thing changed is less saturated fat (and more unsaturated fat instead) the benefit is… nothing at all.

The bottom line? Enjoy your butter and enjoy your steak. Just limit the sugar and carbs and enjoy a healthy low-carb diet.


The Dietary Fat Guidelines Are NOT Rooted in Science

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  1. Harry
    Unfortunately the American Heart Association just repeated their old advice to swap out and drastically limit saturated fats (to 5-10% of calories), and they now specifically included coconut oil on that list.

    “Scientific studies that lowered intake of saturated fat and replaced it with polyunsaturated vegetable oil reduced cardiovascular disease by approximately 30 percent; similar to cholesterol-lowering drugs, known as statins,” the organization said in a "presidential advisory."

    “Several studies found that coconut oil — which is predominantly saturated fat and widely touted as healthy — raised LDL cholesterol the same way as other saturated fats found in butter, beef fat and palm oil."

    “We want to set the record straight on why well-conducted scientific research overwhelmingly supports limiting saturated fat in the diet to prevent diseases of the heart and blood vessels,” said Dr. Frank Sacks, lead author of the advisory and professor of Cardiovascular Disease Prevention at the Harvard T.H. Chan School of Public Health.

    Their list of fats from best to worst thus looks quite unlike those promoted by Team Dietdoctor here:
    Safflower oil: 75 percent polyunsaturated fat
    Sunflower oil: 66 percent polyunsaturated fat
    Canola oil: 63 percent monounsaturated/ 28 percent polyunsaturated fat
    Corn oil: 55 percent polyunsaturated fat/ 28 percent monounsaturated fat
    Olive oil: 73 percent monounsaturated fat
    Peanut oil: 46 percent monounsaturated fat/ 32 percent polyunsaturated fat
    Butter: 63 percent saturated fat/ 26 percent monounsaturated fat
    Coconut oil: 82 percent saturated fat
    Lard: 39 percent saturated fat/45 percent monounsaturated fat
    Palm oil: 82 percent saturated fat/ 11 percent monounsaturated fat

  2. Ashley
    This goes against common sense science and you should be ashamed of yourself for spreading misinformation and heart disease.
  3. Bonita Gates
    I'm excited about joining the diet doctor program. Both my husband and I are diabetic type 2. Not sure how to start the program. Any recommendations.
    Reply: #4
  4. mary bertha
    hi Bonnie
    I am new to this site as well,I am over weight from A LOT of pain meds and other medications ,I have a small crack in my spine and a couple herniated discs that keep me immobile most of the day,the only suggestion I can give you is start anywhere if u don't like the recipe change it up to what u would like but with all the same ingredients this is what I have done since joining 2 weeks ago and I am done 12 pounds I am so freaking happy this is the first diet that is actually helping good luck

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