Protein, ketosis, and lean mass

Most people make a big deal about protein.  I do, too.  Low carb diets aren’t muscle-sparing.  Again.



Comparison of a Low-Fat Diet to a Low-Carbohydrate Diet on Weight Loss, Body Composition, and Risk Factors for Diabetes and Cardiovascular Disease in Free-Living, Overweight Men and Women (Meckling et al., 2004)

Part 1.  Hunger Free Diet(s)

Focus on what they’re eliminating:

LC diet: “limit intake of breads, pastas, rice, and desserts, eliminating intake of deep-fried foods, dried fruit, candy, sweetened soft drinks, and sugar, and increased consumption of vegetables, lean meats, eggs, and nuts”

LF diet: “eliminate high-fat dairy products and substitute with no-fat or LF alternatives, to increase intake of fruits, vegetables, whole-grain breads, and pastas and to eliminate fried foods, cream sauces, and high-fat/sugar cakes, pastries, chocolate, and candy. They were also asked to reduce use of oil products in cooking. As with LC subjects, LF subjects were encouraged to consume lean meats as alternatives to high-fat meat products.”



I don’t care much for “LF alternatives” like low fat yogurt or skim milk, but for the purpose of this study (LF/CICO), it gets the job done.  Both of these are healthy, Hunger-Free Diet(s).  And neither are extreme.



Part 2.  Dismay!

LC dieters lost less fat and more muscle than LF dieters.



So I immediately thought it was either CICO or protein.  The LC group must not have cut enough calories (to explain the “less fat loss”) and cut too much protein (to explain the “more muscle loss”).





Maybe insulin didn’t decline in LC for some odd reason?!!!






Part 3.  Chill, guys.


3a. regular conclusion: Both groups started eating better, lost fat mass, and got healthier.


3b. alternative conclusion: Low carb diets aren’t muscle-sparing and even appear to be the opposite: you need to increase protein to attenuate muscle loss on this diet.  These LC dieters increased protein by 10 g/d and still lost more muscle than LF dieters, whose protein actually declined by ~10g.  If LC was muscle-sparing, the exact opposite would’ve happened.  It didn’t.  Please don’t hate me for this.


Keto works very well for many people!  I’d just say it’d be prudent to increase protein and maybe even take up resistance exercise to spare/preserve lean mass.


Further reading: Muscle growth sans carbs


calories proper


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  • One of the things I realized as Kiefer got popular was that I perhaps had not properly respected my cheats as part of my success. I’d go get ice cream or something once a week or so. Of course, there are a lot of people who claim to go keto and never really do because they cheat too much.

    • I’m glad you found something that works for you

      but imo, cheat meals can be tricky

      timing, frequency, duration… all very context-dependent

      some people do well with ’em, but many don’t

      • Isn’t losing weight statistically impossible? I remember something about losing weight and keeping it off for two years made you an outlier.

        This is all tricky.

        But the long period of low insulin followed by a relatively brief spike seems a lot better than what would happen with an idea like ‘complex carbohydrates’. Especially once it dawned on me that I actually want insulin every once in a while.

  • Interesting! I seem to gain lean mass easily on a VLC diet, but with high protein. I also do punctuated carb refeeds one a week or so. But I may be an outlier.

    • I actually don’t think you’re an outlier

      high protein diet + exercise = gain lean mass

      carbs are more supportive to muscle gainz than dietary fat, but quantitatively, protein & exercise are more important

      • Whew! I’m glad I’m not an outlier! I would hate to note be normal, statistically speaking ????

        • Martin

          And I have no problem maintaining muscle mass and more importantly strength on a LCHF diet with protein coming from meat and eggs in fair but not too extreme amounts (1.5g / kg of lean body mass). The sport I do (bouldering) requires good strength to weight ratio, so muscle gain is not my goal, though. As said, maintaining muscle mass, gaining strength and quick recovery are super easy on LCHF.

  • Ben Green

    Study didn’t measure muscle loss, it measured lean loss using electrical impedance. Low carb dieters lose lbm water through glycogen depletion. Study inconclusive.

  • rs711

    Hi Bill,

    I serendipitously came across this section in Mike Eades’ old response-post to Anthony Colpo just after having read this blog post ( Here’s the quote:

    “But what about the Piatti study, the one that showed the low-fat diet producing more weight loss than the low-carb? I have it marked with an asterisk for a reason. The paper by Piatti et al. titled ‘Hypocaloric High-Protein Diet Improves Glucose Oxidation and Spares Lean Body Mass: Comparison to Hypocaloric High-Carbohydrate Diet’ looked at how 25 obese women fared in terms of lean body mass and insulin sensitivity. They were put on 800 kcal diets for 21 days. It was found that the low-carb diet spared more muscle tissue and improved insulin sensitivity more than the low-fat diet of an equal number of calories”

    Here’s a link to the 1994 Piatti study Here’s a quote from the abstract:

    “In conclusion, our experience suggests that (1) a hypocaloric diet providing a high percentage of natural protein can improve insulin sensitivity; and (2) conversely, a hypocaloric high-polysaccharide-CHO diet decreases insulin sensitivity and is unable to spare muscle tissue.”

    Thought you might find it interesting (despite its methodological limitations).


  • Man

    Hey Bill, to maintain muscle mass in a hypocaloric state, you definitely need some anabolic hormone … something like INSULIN 😀
    Low carb / moderate protein are not anabolic enough. Resistance training will help but you need carbs to be more anabolic. The fat loss is not affected by insulin and carbs, only overall energy balance is important for fat loss : a deficit will make your body rely more on body fat to get by. But for muscle mass maintenance, no way around: you need to be in an anabolic state regularly enough. That is why for true fat loss, I would dial down my fat intake, but maintain a reasonable carb intake and resistance training program. But anyway, if one wants to go keto or VLC for fat loss, that’s not a problem to me and I won’t convince anyone not to try it (Note: I’ve been there as well, and I won’t willingly do it again …).

  • What kind of macros determine LF and LC here?

    • roughly ~15% fat for LF, ~15% carb for LC

      Full text:

      • Eve

        Would females with a lot of subcutaneous thigh fat, and therefore a lot of alpha adrenergic receptors, be better off with higher carbs or keto for maintaining or adding muscle mass? It seems like the two approaches have opposite effects here, but which outweighs the other?

        • if gaining muscle is your goal, carbs are more helpful than dietary fat

  • Martin

    Many problems with the study, again.

    >> Focus on what they’re eliminating:
    >> LC diet: “limit intake of breads,

    We do NOT know what they eliminated, we only know what they were asked to limit.

    >> Low Carb diets aren’t muscle-sparing

    Phinney & Volek claim that a ketogenic diet is muscle sparing. Just going low-carb with emphasis on lean meats can be problematic for all kinds of reasons.

    • Martin

      OK, it was a controlled study, the diet composition was fixed. Given the calorie restriction, they still ate lots of carbs (comparing to a typical carbs to fat ratio of ketogenic diet): ~59g. The claim that Phinney & Volek make is not disproved by this study.