Posted on 24 Comments

Muscle Loss While Dieting to Single Digit Body Fat Levels

A question that comes up quite often is how much fat someone can lose when they are dieting down to the single digit range.  It’s often claimed that losing more than two pounds per week will cause muscle loss or that the ratio of fat to muscle lost will start to shift in a negative direction.  Even that data is usually based on studies of the obese and it is likely to change as people get leaner.  So what’s the reality.  How fast can fat be lost in lean individuals without muscle loss.

The 2 Pound Per Week Limit

The idea that weekly weight loss should be limited to 2 pounds has been bouncing around for decades although nobody seems to know where it came from.  There’s no real physiological reason for this to be a weekly maximum and much larger rates of both weight and fat loss can be achieved with extreme deficit diets.

Ignoring all of the game playing that goes on behind the scenes, Biggest Loser contestants routinely lose far more than that per week, often 10+ pounds.  Studies utilizing a protein sparing modified fast (PSMF) as per my  Rapid Fat Loss Handbook have been measured at 1/2-2/3 pounds of fat loss PER DAY.  Which is 3.5+ pounds of fat per week.  Clearly 2 lbs/week is a bogus value in a physiological sense.

So where did 2 pounds come from?  I suspect it was mostly a behavioral/reality issue.

Losing one pound of fat is usually assumed to require a 3,500 calorie deficit.  To lose even 2 pounds per week then requires a net weekly deficit of 7000 calories.  That’s 1000 calories per day.

This is a very large deficit which will require either a large amount of activity (2 hours+ for an untrained individual) or fairly large-scale calorie restriction.  Certainly this can be achieved with extreme diets but I suspect that the 2 lb/week rule came out of this idea.

For most people, a larger deficit than 1000 calories per day simply isn’t realistic.  I’d note that this was during a time when it was generally felt that more rapid fat loss was associated with poorer long-term results.  But depending on how it’s done, rapid fat loss may be superior.

Mind you, weight loss isn’t fat loss and the issue of muscle loss is a concern.  When dieting we want to improve body composition.  And initial bodyfat percentage plays a large role here: leaner individuals are more at risk for muscle loss than those carrying more bodyfat.

Rapid Weight Loss and Muscle Loss

Another issue was that analyses of the studies, always done by Gilbert Forbes, suggested that more extreme deficits caused more greater muscle loss.  But there were two major problems with this conclusion.

  1. There was no exercise, especially weight training, done.
  2. The caloric intake was stupid low.

We know that exercise spares muscle loss when dieting.  And while all types of exercise will help in total beginners, weight training is invariably found to be superior.  When most of the research on this was being done, weight training wasn’t particularly mainstream so it was never included.  If the dieters exercised it was invariably aerobic exercise.  And often no exercise was done.

And while that’s important, the second issue is probably the biggest one.  Many of the early Very Low Calorie Diet (VLCD) studies used insanely low intakes.  I am talking about things like 200-400 calories per day.  And frequently the diets were at most 50% protein.  So realistically you had people eating 100-200 calories per day of protein or 25-50 grams of protein.

Now, even those individuals with extremely high body fat percentages have some minimum protein intake requirements.  And most of these VLCD’s didn’t come close to providing it.  This is fundamentally why I set up my the Rapid Fat Loss handbook up around protein intake rather than calories.  You have to meet protein requirements on a diet or it will fail.

And when researchers finally started providing sufficient dietary protein, usually in the realm of 1.5 g/kg (0.7 g/lb) of lean body mass with a PSMF, muscle loss stopped.  It was almost as if protein was protein sparing or something.  For a 300 pound individual with 40% bodyfat, that calculates out to 122 grams of protein per day which is about 500 calories minimum. Add in some tagalong carbs and fats and you get higher calories than that.   Simply, setting calories at 300/day doesn’t allow sufficient protein.  Yet most of the data on this came from diet studies that did exactly that.

Lean vs. Obese Individuals

For what should be fairly obvious reasons, obesity researchers don’t do fat loss studies in lean individuals for the most part.  Rather, all of the research above comes from studies in the obese.  And the fact is that the system does change as people get leaner.

More work by Gilbert Forbes showed clearly that initial body fat percentage impacted on the ratio of fat and muscle mass that was lost.  On average, leaner individuals lost more than those carrying more fat.  Some early work suggested that, when you were lean, you’d lose roughly 1 pound of muscle for every 3 pounds total weight lost.  That is, up to 33% of your total weight loss might be muscle.

Many if not most aspects of physiology change as people get leaner and this is one of them.  It’s also why almost all of my book use a Category system based on bodyfat percentage for diet set up.  The reasons for the increased risk of muscle loss is multi-factorial and relates to calorie partitioning.  There are hormonal effects along with the relative difficulty of using fat versus muscle for fuel.

With the idea that faster weight loss led to more muscle loss, suggestions to limit weekly weight loss to one pound per week when you got lean were often made (other systems will use a percentage of current bodyweight based on BF%).  Dan Duchaine echoed this in the seminal Bodyopus and for a long time I suggested 1-1.5 lbs/week as the “sweet spot” for weekly weight loss for leaner individuals.   It’s still not a bad value for people on a moderate deficit.

But it’s not an absolute value.  Some can lose faster than this as people who use my Rapid Fat Loss handbook diet have shown.  True fat losses of 2-3 lbs/week in lean individuals without significant or any muscle loss is achievable for at least short periods of time in leaner individuals.  But it’s a couple of weeks tops before a break has to be taken.

But the 1-1.5 lb/week value isn’t an absolute, some can lose faster than this as lean people using my Rapid Fat Loss Handbook have shown.  True fat losses of 2-3 lbs/week in lean individuals is possible at least for short periods of time (one limitation of the RFL approach for lean people is that it should only be used for about 2 weeks straight before something less extreme is done).

So clearly it is possible to lose more than the stock-standard 1-1.5 lbs/week of true fat without muscle loss.  And understanding why and how means understanding why muscle loss tends to occur on a diet in the first place.

Why Does Muscle Loss Occur During a Diet?

There are a number of reasons that muscle loss tends to accelerate as people get leaner.  One is that the person has less bodyfat.  As fat cells shrink, it becomes more difficult to mobilize fat from them for energy.  So the body has to find something else.  That something else is usually muscle.

For that reason, protein requirements also go up as people get leaner, often reaching requirements of up to 1.5 g/lb lean body mass.  Yes, this is 1.5 g/lb lean body mass, not the 1.5 g/kg that is sufficient for the obese.

Beyond that, the big reasons are hormonal.    As people get leaner during a diet, leptin falls as does testosterone (often reaching castrate levels at the extremes of leanness).  Cortisol goes up which can hasten muscle breakdown, thyroid falls, metabolic rate falls, etc.  It’s one giant set of metabolic adaptations that the body makes to try to keep you alive.  And these factors all become more pronounced the leaner you get.

I’d note in this regard that if you look at the strategies used by professional bodybiulders, they are invariably using drugs to help offset all of the problems I’ve described.  With enough testosterone, thyroid medication, thermogenics such as clenbuterol, anti-cortisol compounds and appetite suppressants, they can show an effectively normal physiology while dieting to the extremes.

Now, these factors reverse themselves when people raise calories.  Various cyclical diets such as my own Ultimate Diet 2.0 or strategies such as The Full Diet Break can all help to normalize hormones and help to avoid all of this.   Recent research on the topic has actually finally caught up to what I was writing about in 2004 in this regard.


An additional factor is that people’s ability to train intensely often goes down on a diet and maintaining the appropriate tension stimulus to keep muscle is key to avoiding muscle loss.    The entire idea of training with less intensity and more volume on a diet is asinine and only works for steroid users.  The key to avoiding muscle loss is to maintain at least some heavy training. This is what builds muscle and this is what maintains it.

But the ability to maintain training intensity in the face of a long diet at low body fat percentages is often impaired.  If the lifter can’t maintain their intensity in the gym, muscle loss is more likely.  This is yet another reason to use various cyclical dieting strategies such as refeeds or diet breaks.  By restoring muscle glycogen and raising calories, training intensity invariably improves.    This is in addition to the beneficial hormonal effects.

Dieting in the 1980’s and 1990’s

In the 1980’s and 1990’s, natural bodybuilders had all kinds of problems with muscle loss which is what led experts like Duchaine to set a 1 lb/week limit.  But the dieting practices of the time were also pretty awful.  Invariably they included:

  1. An increase in training volume with a decrease in intensity
  2. Excessive aerobic training
  3. Protein intakes of only 1 g/lb bodyweight

And when you combine those three, muscle loss is almost guaranteed. As well, nobody utilized refeeds or diet breaks.  It was just straight dieting in attempt to make it to stage.    And that just compounded a lot of the problems.

Don’t get me wrong, some people still made it work.  Why?  I can’t say.  But I would say that more had problems with the traditional approach than succeeded with it.  Many dieters probably gave up due to excessive muscle loss so what you were invariably seeing was the survivors who made it work.  And that’s misleading.

But so long as you do the opposite of those things, fat can be lost faster than 1 lb/week without muscle loss.  First, keep weight training intensity as high as you can. If you can maintain your poundages on the bar, you should.  Never cut intensity for volume and be prepared to drop volume if you need to.  Because 3 heavy sets will maintain muscle better than 6 lighter sets.

To that use cardio in a targeted manner.  Yes, some people need more than others especially as metabolism adapts down and down over the course of a diet.  If you need to do an hour per day to get lean, that’s fine.  Make sure to work up to it over the course of your diet.  But don’t do it just to do it.  Do it because you need it.

To that add sufficient protein.  For a male in the single digits, I recommend 1.5 g/lb lean body mass of protein.  Yes, this is a lot.  But that’s what is necessary.

Then strategically use refeeds and diet breaks as needed. Have one or two high calorie/higher carbohydrate days per week during the diet.  If that’s not a good approach for you, take a 7-10 day break at maintenance every 4-6 weeks.  Yes, your diet will take longer but it will work better in the long-run.

Because if you do that, you should be able to achieve a single digit body fat without muscle loss, even at fat loss rates of greater than one pound per week. With an extreme diet you might even get 2 lbs per week but you can only do it for a couple of weeks at a time.

Or if you don’t want to do that, and choose to diet in the inefficient ways that people did it 2 decades ago, you should probably stick with one pound per week to be safe.  Or, just don’t do that.


Similar Posts:

Facebook Comments

24 thoughts on “Muscle Loss While Dieting to Single Digit Body Fat Levels

  1. “1.5 g/lb should probably be the minimum while dieting (certainly some people get away with less but this is highly individual)”

    Is this per pound of LBM or per pound of bodyweight?

  2. Waffle,

    I think Lyle’s covered that somewhere on the site in one of his questions. The answer is to err on the side of total body weight, unless you’re carrying alot of bodyfat, in which case LBM approximations are more appropriate.

  3. Andrew is correct as well as the simple fact that, anyone for whom this article applies (e.g. approaching single digits), the difference in total and lean body mass is at most 10% (e.g. if you’re 10% bodyfat). The difference in daily protein intake will therefore be pretty small regardless of the value you use (esp. within the range of weights you see in natural individuals).

  4. Would 1.5 g of protein/lb also apply to those on a ketogenic diet with weekend refeeds?

  5. But were you talking just for the RFL or general dieting like Flexible diet sort of dieting? If a 170 pound guy with 10% BF eats 150g carbs and 180-200g of protein combined with a 500kcal daily deficit, would protein need to be higher as you said in The protein book? Could carbs in this situation be at least muscle sparing, and allow a bit lower protein amount?


  6. What are your thoughts on this diet?

    The premise is a “slow-carb” diet w/ a once weekly cheat day to reset metaboism related hormones. Carbs can also be eaten within 90 minutes of completing a full body workout.

    I’ve been dieting off and on for quite some time using this type of system, but I feel that my metabolism and testosterone levels may be very very low from such a long period of very restrictive dieting. Before starting this diet I was restricting calories severely w/out paying any attention to macronutrient profiles. Although, I’ve been much happier mentally on this diet, I haven’t lost the weight I’d like to.

    I think I’ll up my exercise and increase calories + carbs for the next two weeks to see if I can get my metabolism back in order.

  7. John: Protein intake sort of ‘lives outside’ of the rest of the diet unless you’re talking about something super extreme like the Rapid Fat Loss diet. As noted in the article, there is some variance in this. Some do just fine with 1 g/lb

    Harold: See my response to John.

    Aaron: Yeah, I called that a Targeted Cyclical Ketogenic diet in my first book over 15 years ago. Please also read the article on the site titled “The Full Diet Break”.

  8. If you are gonna make Q&A articles, you should make the answer more spesific and not way out of the context of the question. You are talking more about the physiological limits of fat loss and general dieting guidelines, than talking about the spesific situation of the question.

  9. Everything discussed above was relevant to the question and I’d rather give folks the background to understand why I’m saying what I’m saying than to just say it.

    But here’s something neat: if you don’t like how I write, you don’t have to read it.

  10. I’m not saying i don’t like the writing. Just merely suggest you be more spesific when you do Q&A. Why not just make it a regular article and adress every single situation more indept?

  11. Lyle,just received your Ketogenic diet few days ago & was wondering if frequent refeeds is really necessary for lean individuals using the targeted keto approach?My body fat plays around 6-7% as of the moment,how often would you recommend refeedings during extreme leanness?

  12. As per my response on the support forum, refeeds essentially ‘live outside’ of the specifics of the diet because leptin and the rest will go down as fat is lost/in any deficit. So yes they are still needed and a frequency of perhaps 5-12 hours every 5th day or 24 hours every 7 days would be appropriate at that body fat level.

  13. Great article, Lyle. Your 1.5g/lb suggestion has been super helpful – I had been suffering muscle loss as I venture below 10% body fat, but that has now stopped.

  14. Just wanted to say thanks for another good article.

    However, after reading quite a few of your replies, I’ve come to the conclusion that lyle is an asshole.

    Just wanted to put it out there.

    In the end, what’s the point of being fit and healthy if everyone thinks you’re an asshole ?

  15. Thank you for noticing, Bob. I’ve worked very hard to become what I am and would hate that some internet person didn’t notice my hard work.

    Question back at you: what does my personality have to do with anything? Does Tiger Wood’s personality issues detract from his golf skills? Or can you not make the distinction between the two?

  16. Lyle, Personality has nothing to do with your writings, and nothing to do with the fact that you are generally heralded as an authority in the field. Plus, I think that such a demeanor results from being of superior intelligence. Tiger woods is good at Golf, and that is all anyone should care about.

    I’ve read a lot of your work, but as far as I can tell you’ve never detailed your personal “diet”. If you have, maybe you could point me in the right direction? Thanks.

  17. I’d rather have correct information with someone being brutally honest about dieting than keep on living in lala-land. I am extremely thankful for Lyles writing. If he would not have written the stuff that he does I would not be where I am today bodycomp-wise. I’m sure thousands of others would say the same thing.

    Personality does matter in relationships with a person but I really appreciate Lyles honesty, internet would suck allot more without him. I’m a rational person and I think more people should be instead of doing stupid stuff.

  18. Let it go. Seriously, just let it go. Frameless was just a little whiner anyhow.

  19. Much of human persuasion has to do with being liked to a large degree before people will even be ready to accept the written or spoken views of the presenter. Lyle could probably do more with the opporunity before him. Obervance of Lyle’s comments and “scientific” writing leave much to be desired as far as being applicable to many situations addressed in his writing from a mature and peer point of view. Practical obervance of human and non-human situations have repeatedly contradicted his opinion. This subject is a good example, as is this comments section.

    He states opinions of others he seems to accept and respect and then closely says basically the same thing, often not what he himself found in practical or live situations. This shows a lack of being detailed as many notice.

    Being rude to others turns them off to accepting any validity Lyle does have in his writing and thus limits his audience. Lyle responds negatively and defensively to being questioned and innocent suggestions. That is a poor combination for science and persuasion and even for informative purposes. Lyle seems comfortable with his writings and personality though. Pity.

  20. Here’s something for you and Frameless to consider: IF YOU DON’T LIKE WHAT I HAVE TO SAY OR HOW I SAY IT THEN DON’T READ THE SITE.

    Seriously, what is with the constant whingeing on the Internet these days, is it the estrogen in the water bottles? Because if all you folks who have NOTHING better to comment on is that I’m an asshole, then your lives must be very very very empty.

    That’s the real pity. That you bitch about me but we both know you read my site constantly. You can’t help yourself. Your like the idiots who complain about Howard Stern, and listen to him every day. Get a life, find something better to do than read a site when it gives you so much angst.

    No-one is forcing you to be here, no-one is forcing you to read my articles. So if all you can do is bitch, it’s easy: leave. Take my site out of your bookmarks or Google reader or whatever.

    But spare me the whining. It’s just pathetically sad.

    Don’t like it? Then don’t read it. It seems altogether too simple.

  21. say you were on a diet for (insert amount of time here) and your hormones were falling, would starting to take ephedrine help with hormone levels at all? if not, then would it be best to start taking ephedrine after a diet “break”?

  22. The only hormonal system that the EC stack can possibly ‘fix’ is reduced sympathetic nervous system drive which is one of many that goes down with dieting.

  23. Really enjoyed this article, thanks Lyle. Very interesting. I’ve been guilty of too much volume and not enough intensity, a good reminder

  24. I enjoyed the article, but would like clarification. You mention early in the article that protein of 1.5 g/kg of lean body mass is required, then later you mention 1.5 g/lb of lbm. Could you please clarify which is appropriate?

Comments are closed.