Muscle Loss While Dieting to Single Digit Body Fat Levels – Q&A

Question: My question is about what the maximum amount of fat that can be lost per week when someone is in single digit body fat percentage. I’ve heard it kicked around that once you start losing greater than 2 pounds or so per week that the ratio of fat to lean tissue loss starts to migrate towards the uglier side of things. However, this is presumably for people with higher body fat percentages not trainees who have been dieting for awhile to get to single digit body fat. My guess is that the hormonal and general homeostatic adaptations that occur during prolonged dieting and fat loss skew the muscle to fat loss ratio independent of any metabolic adaptation.

I realize that there are no hard and fast rules here, but do you have a figure kicking around that brain of yours that articulates what is the maximum amount of fat loss per week while maintaining a decent  fat/muscle loss ratio once someone has approached single digit body fat? I’m guessing it’s no where near 2 pounds at that point.

I’m at about 9% and I’m regularly hitting a 7,000 calorie deficit (Bodybugg) and I’m starting to see my strength levels go down regularly for the first time. It looks like I’m starting to lose a little muscle too but I’m not skilled enough with the calipers to know for sure. Obviously I need to cut back on the deficit and see how things go but it made this question pop in my head. Hope you can use it on your site sometime. Thanks for all your hard work and great info.

Answer: The short-answer, as always, is that it depends.  Now here’s the long answer.

First, the idea that 2 lbs/week is the maximum amount of weight/fat loss that should be achieved has been around for years but nobody seems to know where it comes from.  Certainly there’s no physiological reason for this to be a maximum and much larger rates of true weight/fat loss can be achieved with extreme deficits.

Anyone who has watched The Biggest Loser knows this to be true and even without that level of asininity, very large folks following a protein-sparing modified fast 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.  Assuming a value of 3,500 calories per pound fat loss (and I’d note that this value has some issues inherent to it discussed in The Energy Balance Equation), to lose even 2 pounds per week means a net deficit of 7,000 calories per week or 1,000 calories per day.

Which means either a lot of activity (a minimum of 2 hours for someone relatively untrained) or fairly large-scale caloric restriction.  Now, certainly this can be achieved with extreme diets but my guess is that the practicality of the 2 lb/week rule came out of this idea: for most people, a larger daily deficit isn’t realistic.  At the time it was also assumed that faster weight loss was associated with poorer long-term results but, as discussed in Is Rapid Fat Loss Right For You?,  depending on the specifics, the truth is actually exactly the opposite of that idea.

Of course, weight loss isn’t fat loss and the issue of muscle loss is a concern, I discuss this in detail in What Does Body Composition Mean? as well as elsewhere on the site.  Another issue regarding the 2 pound per week rule is muscle loss while dieting; this is (or at least should be) a concern and, certainly early studies found that bigger deficits caused greater muscle/lean body mass lost.  But there were at least two problems with this:

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

Number 2 is of course important, while all types of activity will spare some muscle in beginners on a diet, weight training is probably the best overall approach.  And it simply wasn’t a part of mainstream weight loss approaches or research when most of the work was being done.

Even there, number 1 is probably the bigger issue here.  Even very obese individuals need a certain amount of dietary protein to prevent muscle loss and when you only feed someone 300 calories/day, even if 100% of it is protein (and most very low calories aren’t because they are set up stupidly), that’s a maximum of 80 grams of protein.  Which is usually too little.  And is also is why I set up the Rapid Fat Loss Handbook diet by protein intake and not by calories.

You have to meet protein requirements on any diet to limit muscle loss; when researchers started giving obese folks a minimum of 1.5 g/kg lean body mass of protein on a PSMF approach, muscle loss stopped.    For a 300 pound individual with 40% body fat, that’s a daily protein intake of 122 grams per day or a minimum of 500 calories.  With tagalong carbs and fats, total daily caloric intake will be higher. Simply, setting calories at 300/day won’t allow sufficient protein; yet many of the data points came from exactly those studies.

Of course, all of the above really applies mainly to overweight individuals; for what should be obvious reasons obesity researchers tend to not care about fat loss in lean individuals.   However, there was work done on changes in body composition, usually during starvation (and most of this was by Gilbert Forbes who literally spent 30 years writing about the topic) showing that one of the primary predictors of what was gained or lost during over- or under-feeding was initial body fat percentage (discussed in detail in Initial Body Fat and Body Composition Changes).

And, as per that article, as folks get leaner, for reasons discussed in detail in Calorie Partitioning Part 1 and Calorie Partitioning Part 2, muscle loss tends to increase.   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.

And with the idea that faster weight loss made muscle loss worse, suggestions to limit weekly weight loss to one pound per week when you got lean often were made.  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 moderate deficit diets, mind you, and I use that as the sweet-spot value in Adjusting the Diet.

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.

Arguably the biggest reason (and the one we have only limited ability to control) is  shifting hormones: falling leptin and testosterone, increases in cortisol, and a whole bunch of other (bad) stuff happen during dieting and most of these things become more pronounced the leaner you get.   Cyclical diets (like the Ultimate Diet 2.0) and strategies such as The Full Diet Break go a long way towards helping with those issues since the periods of high-caloric intake help to restore hormone levels back towards normal (they can’t ever restore them completely).

Of course, as noted in those articles, a big reason bodybuilders use so many drugs is to fix problems while dieting. With enough testosterone, thyroid meds, thermogenics, anti-cortisol compounds, appetite suppressants, etc. they can basically replace everything that the body isn’t making anymore.

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.  This is one of the reasons I find the whole idea of increasing volume and frequency of training on a diet half-assed; as discussed in Weight Training for Fat Loss Part 1 and Weight Training for Fat Loss part 2, people do better when they cut volume and frequency and focus on maintaining intensity.

Diets such as the Ultimate Diet 2.0 get around this by having the heaviest workout after carb-loading (so you can go heavy) and even basic cyclical ketogenic diets help with this.  Refeeds refill muscle glycogen and that allows people to go heavier in the weight room; strength isn’t a perfect proxy but if you’re keeping your weights up in the gym, you’re probably not losing muscle.

I actually think that training poorly is part of why guys like Dan Duchaine found that more than 1 lb/week fat loss was too much without props.  Training in the 80’s and even early 90’s while dieting was often done in a rather stupid fashion.  People trained too many days with too much volume and often dropped intensity too much because of it.  That alone allows muscle loss to occur.

Coaches who use lower volume and/or lower frequency but higher intensity training on a diet don’t see that level of muscle loss on a diet (if they see any at all). As noted, people on the Rapid Fat Loss Handbook diet don’t report muscle loss so long as they do the training (low volume/low frequency/high-intensity) in the book.

Excessive amounts of cardio contribute to this as well.  When you have drugs to spare muscle loss, 2-3 hours/day of cardio is fine and lets you eat more.  For naturals, while it’s sometimes necessary to go to 2 hours/day at the end of a diet (to offset a cratering metabolism), too much cardio just causes the muscles to fall off on a diet.  Especially when combined with a big deficit and inadequate protein.  But people did (and still do) nutty shit when they diet to get lean; excessive cardio is part of that.

Adequate protein is also a big issue.  For years I went with the stock standard 1 g/lb but on a diet this is probably insufficient.  As I discuss in detail in The Protein Book, 1.5 g/lb should probably be the minimum while dieting (certainly some people get away with less but this is highly individual).  On extreme approaches, more than that (2 g/lb) may be needed.

So bascially if you look at old-school dieting for lean individuals, it had some major flaws including

  1. Often (not always) inadequate protein.
  2. Stupid training.
  3. No use of refeeds or full diet breaks to reset hormones and allow better training to be done.

And while certainly many make the above work, just as many (if not more) have issues with strength and performance loss.

So what’s the answer to your question after all of that?  Well it depends.  If you insist on doing things badly, training too much, excessive cardio, inadequate protein, too stubborn to use refeeds and diet breaks, the old value of 1 lb/week may be exactly right with 1.5 lbs/week maybe being achievable.

Do things in what I consider the ‘right’ way (proper training, adequate protein, refeeds/full diet breaks used) and you can get faster fat loss per week without performance or muscle loss.  1.5 lbs/week is usually achievable for most and, for short periods, with extreme diets, more than that can be achieved without muscle loss.

Of course, there is still individuality in all of this probably relating to genetics and hormone levels.  Some people lose muscle more than others, they have to go with slower rates of fat loss even if they do everything ‘right’.  And others are lucky, they lose fat more easily (some of the reasons are discussed in The Stubborn Fat Solution).  But they tend not to be in the majority of trainees (they are usually in the majority of folks who get on stage).



24 thoughts on “Muscle Loss While Dieting to Single Digit Body Fat Levels – Q&A

  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. 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?


  5. 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.

  6. 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”.

  7. 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.

  8. 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.

  9. 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?

  10. 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?

  11. 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.

  12. 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.

  13. 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 ?

  14. 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?

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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”?

  20. 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.

  21. 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?

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