Low Fat Bests Low Carb In Six Month Trial And Low Carb Advocate Honestly Admits It


Honesty must be acknowledged, and especially in a person whose general preference and advocacy runs counter to what he’s reporting.

Now, whether or not Bill Lagakos would characterize it like that or not, that’s just my take. Bill reports results on a recently published Chris Garner study, Weight loss on low-fat vs. low-carbohydrate diets by insulin resistance status among overweight adults and adults with obesity: A randomized pilot trial.

OBJECTIVE: To test for differential weight loss response to low-fat (LF) vs. low-carbohydrate (LC) diets by insulin resistance status with emphasis on overall quality of both diets.

METHODS: Sixty-one adults, BMI 28-40 kg/m(2) , were randomized in a 2 × 2 design to LF or LC by insulin resistance status in this pilot study. Primary outcome was 6-month weight change. Participants were characterized as more insulin resistant (IR) or more insulin sensitive (IS) by median split of baseline insulin-area-under-the-curve from an oral glucose tolerance test. Intervention consisted of 14 one-hour class-based educational sessions.

RESULTS: Baseline % carbohydrate:% fat:% protein was 44:38:18. At 6 months, the LF group reported 57:21:22 and the LC group reported 22:53:25 (IR and IS combined). Six-month weight loss (kg) was 7.4 ± 6.0 (LF-IR), 10.4 ± 7.8 (LF-IS), 9.6 ± 6.6 (LC-IR), and 8.6 ± 5.6 (LC-IS). No significant main effects were detected for weight loss by diet group or IR status; there was no significant diet × IR interaction. Significant differences in several secondary outcomes were observed.

CONCLUSIONS: Substantial weight loss was achieved overall, but a significant diet × IR status interaction was not observed. Opportunity to detect differential response may have been limited by the focus on high diet quality for both diet groups and sample size.

…So, low fat did better than low carbohydrate. Read it and weep.

Here’s Bill:

Low carb diet: participants went from 230 grams/d to less than 50 for the first 3 months, then creeped up to ~80 over the next 3 months.

Will the critics say “the carbz weren’t low enough!”?  REALLY?


In brief, the one-size-fits-all diet theory is #fail.

Don’t be tied down to one approach; different #contexts require different approaches, and both can change over time.


To make a long story short, insulin sensitive patients randomized to the low fat diet lost about 20% more weight than those randomized to low carb.  Read that sentence again (just the part in bold).

Insulin sensitive dieters lost more weight on a high carb diet than a low carb diet (10.4 vs 7.4 kg).  Insulin resistant dieters lost more weight on low carb (9.6 vs 8.6 kg).  Notably, of all four groups, the most weight was lost on a high carb diet (10.4 kg) despite low carbers consistently getting more protein.

Don’t be a science denier!


Are these data meaningful? YES

I say this because the differences are very close to the magnitude we’d expect in these populations.  Insulin sensitive dieters lost 20% more weight if they were assigned to a low fat diet, but they still lost weight on low carb…  we wouldn’t expect insulin sensitive dieters to gain weight on a low carb diet, just lose a little less because it’s not optimal in this #context.

Are there a million other factors involved here?  YES.  Insulin sensitivity  is only one of ’em, but a pretty good starting point.

Theoretical scenario: a sedentary, obese insulin resistant patient starts off on LC and is initially successful.  They start exercising and focusing on sleep quality, insulin sensitivity improves (ie, new #context)… but weight loss stalls in many of these people.  Maybe at this point they would benefit more by switching the focus from strict LC to monitoring other things, like calorie or fat intake (ie, to match the new #context) –> progress resumes.

Don’t be tied down to one approach; different #contexts require different approaches, and both can change over time.

Honesty is refreshing. An open question for me is whether an LC approach helps insulin sensitivity or harms it (physiological IR). Perhaps that’s individual too. Sure was for me, both fasting and post-meal. Potatoes and beans fixed that, and now I’ve tossed whole oat groats into the mix, rounding out my “Peasant Diet.” It has done so for others as well, and I predict it will only get bigger. The bottom line for me is whatever you do, limit it to whole foods, and low carbers also need to come to grips with the fact that oils are not whole foods. They are processed foods.

Richard Nikoley

I'm Richard Nikoley. Free The Animal began in 2003 and as of 2021, contains 5,000 posts. I blog what I wish...from health, diet, and food to travel and lifestyle; to politics, social antagonism, expat-living location and time independent—while you sleep—income. I celebrate the audacity and hubris to live by your own exclusive authority and take your own chances. Read More


  1. wallycat on March 27, 2016 at 08:38

    This is why my comment (somewhere on this blog) is that NO diet works the same for everyone. There is no one-diet-fits-all.
    Unfortunately, the population at large is getting more and more insulin resistant. Yes, all the other factors that we do not know about probably apply but if don’t know them, you can’t deal with them. That’s the frustrating part. Diabetes diagnosis is increasing.
    In a perfect world, as many have said here, moderate food consumption (I think these huge portions have done us a dis-service) balanced with fat, carb, protein may never have gotten many of us (insulin resistant) folks to where we are today.

  2. PhilT on March 27, 2016 at 10:33

    “No significant main effects were detected for weight loss by diet group or IR status; there was no significant diet × IR interaction”.

    So there was no difference in anything beyond that which could have occurred by chance ?

    • Richard Nikoley on March 27, 2016 at 11:43

      I’ll refer you to Bill’s comment on that, and I agree with him. Also, they were not testing for significant weight loss, or even dietary comparison. They were testing for whether insulin sensitivity or resistance makes a huge difference and that’s what wasn’t statistically significant. All subjects lost weight.

  3. king of the one eyed people on March 27, 2016 at 14:49
  4. solver on March 27, 2016 at 15:54


    just an update fyi: I tried potatoes, usually with meat as a protein source and always low, low fat but I still found I lacked my potential in terms of energy (measured via max lifts at the gym).

    So I tried beans instead. Wow! It does everything you say potatoes do but I feel even more energized. I suspect it may have something to do with the protein content in the beans. For me every meal is about 50% beans by weight plus other vegetables (some potatoes but mainly greens) and meat. Mostly soups. Oh, and I add gelatin to my soups – works a treat and boosts the protein content with zero fat contribution.

    Potatoes are (mostly) out and beans are in for me!

    Love always Richard. Solver.

  5. solver on March 27, 2016 at 19:31

    Oh, and re: podcast, maybe try and find some of the ‘lost’ paleo brigade such as Kurt Harris and Art Devany? It would be cool to see what they’re up to now. What’s life like after paleo?

  6. Hapennybacon on March 28, 2016 at 07:23

    Has anybody read the whole study? What about fatloss?
    Simply shrinking obese people doesn’t make them healtier.

    • Richard Nikoley on March 28, 2016 at 08:03

      I think all this fat loss vs. lean loss LC and Paleo peeps engage in is bunk.

      In 1981, 10 IRA prisoners starved themselves to death via hunger strike. They all died in the 60-75 day range with no food. In that time, they lost 95% of their body fat but only 19% of lean mass.

      In general, obese people will be healthier on any diet that loses weight, because the vast majority will be fat, no matter the diet. Also, in weight gain, about 25% is lean anyway, so some lean loss in a weight loss program is to be expected.

  7. John Bafaro on March 28, 2016 at 10:40

    I’m curious as to the grams / day of fat the LF group consumed.

  8. A. Velez on March 28, 2016 at 12:12

    An important “detail” that is not in the abstract tells me that the real food strategy is a winner anyway:

    The fourthstrategy was to promote high nutrient density (Quality). Other Qual-ity concepts included “real food,” “minimally processed,”“seasonal,” “organic,” “grass-fed,” “whole grain,” and “pasture-raised,” depending on diet assignment. Both diet groups receivedsimilar instructions to drink water, maximize vegetable intake, andto minimize added sugars, refined white flour products, and sourcesof trans fats.

  9. Mike on March 28, 2016 at 12:36

    Reconfirms what Chris Gardner found in his early study. If you are IS then HC is better, If you are IR, then LC is better (didn’t see this part in your post) .

    Good path to weight maintenance and health is probably LC until you fix the IR at which point you wll probably plateau, then add carbs to get to your goal weight. From there whatever you can stick to.

    • thhq on March 28, 2016 at 18:44

      That is how the old ADA carb counting protocol works. It’s effective for flattening blood sugar spikes and controlling diabetes, but it also works for weight loss. It’s Atkins with nuance and brains, and of course uncredited by HFLC Nation.

  10. john on March 28, 2016 at 15:37

    The results section states “Six-month weight loss (kg) was 7.4 ± 6.0 (LF-IR), 10.4 ± 7.8 (LF-IS), 9.6 ± 6.6 (LC-IR), and 8.6 ± 5.6 (LC-IS)” and Bill states “Insulin sensitive dieters lost more weight on a high carb diet than a low carb diet (10.4 vs 7.4 kg). Insulin resistant dieters lost more weight on low carb (9.6 vs 8.6 kg)”. Looking carefully, he is making incorrect comparisons. 7.4 kg and 10.4 kg pertain to the low fat groups (IR and IS respectively), and should not be compared as high carb vs low carb; likewise for the 9.6 kg and 8.6 kg comparison. Additionally, these error bars are enormous, and a valid conclusion of which approach is better cannot be made. If one takes the averages of the low fat vs low carb groups, the low carb group actually loses more weight (9.1 kg compared to 8.9 kg). Another thing not mentioned is the quality of the calories-micronutrients may have a large effect on metabolism. All in all, this study does not demonstrate any significant difference between low carb vs low fat.

    • Richard Nikoley on March 28, 2016 at 15:53

      You mean takes the averages of the already averaged numbers.

      The only way to know how much weight was lost is to cumulatively total weight loss, subject by subject.

      The most significant thing about the study is I’m not seeing it touted as a victory for LC anywhere.

  11. thhq on March 28, 2016 at 18:33

    First of all I must point out that this is a pack of lies which are are result of soft science, illustrated on pg 232-234 of GCBC. Oh wait, the whole foundation of the carb insulin assertion – NHANES dietary recall surveys – is fraudulent….nevermind…back to the original program…

    And what did anyone reasonably expect? EVERY weight loss diet, high or low carb, works if you follow it. In another study low carb might incrementally outperform low fat over six months. That doesn’t make either of them a pattern for a long and healthy life. They’re both ER treatments.

    What it looks like over 50 years is what interests me at this point. I’m done losing weight. My obesity crisis is over. For me the question is what would Ancel Keys and Jack Lalanne do? How do you live long and healthy? One thing for sure is that it’s not a high fat OR a low fat diet. From what I observe, It’s a balanced diet with a lot of activity, both mental and physical. And a sense of calm about it. What you did yesterday to be happy and healthy is what you do today is what you do forever. Boring but effective. Nobody reads Eat Healthy and Stay Healthy anymore. But they should.

    • Richard Nikoley on March 28, 2016 at 18:56

      “I must point out that this is a pack of lies which are are result of soft science”

      That’s simply the coolest passive-aggressive thing I’ve seen lately.

  12. Paul on March 29, 2016 at 10:39

    I failed to see the besting described in the title.

  13. JJ on April 3, 2016 at 06:07

    My own personal experience is low carb is the only thing that worked for me. Technically I had a suitable BMI but only 2 to 3 pounds before I would move into “overweight” BMI. I don’t know if I’m insulin sensitive or resistant but after 15 years of eating low fat, and attempting to restrict calories on a low fat diet, I weighed exactly the same. As soon as I started eating more fat, mostly from nuts but also from butter, and cut the grains and sugar in yogurt and coffee, I lost weight.

    But I definitely believe there is no one size fits all. White potatos do not agree with me at all. One tiny potato and I’ll have gained weight the next day.

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