Question: Is it possible to stay at the same weight and replace fat weight with LBM, by making decent strength gains over time? (i.e by not actually leaning out and then mass packing etc). Can the body use the extra calories that are needed for new muscle gain from existing fat stores on the body? I’m assuming this is the case for beginners, but how about intermediates/advanced trainees? If so, roughly what sort of time frame would be needed to say drop 10lbs fat and replace with the same amount in muscle? Thanks.
Answer: I’m willing to argue that if there is a single question (or related set of questions) that comes up perennially in the field of training and nutrition, it’s something akin to the above. The idea of ‘gaining muscle while losing fat’ in general or, better yet ‘replacing every pound of fat lost with muscle’ is sort of the holy grail of training and nutrition and a great deal of approaches that are supposed to generate that very thing have been thrown out over the years.
In essence, this is the basis of bodyrecomposition, you train and eat in such a way as to end up with more muscle and less fat than you had before. People on forums either want to know how to accomplish the above or make statements such as “I want to gain muscle without gaining weight.” implying that they are replacing every pound of lost fat with the exact same pound of muscle. Others will hide it in the math of the situation, wanting to move from one weight/body fat percentage to another without recognizing what that implies for the numerical changes that they are seeking.
Now, when I was younger and only thought I knew what I was talking about, I would often say that the above was impossible to accomplish. In hindsight, impossible was a bit too strong of a term; clearly it’s not impossible as it does happen. But it can sure be difficult depending on the situation.
There are a handful of situations where the combination of muscle gain and fat loss occur relatively readily. The first of those is in overfat beginners. I want to really stress the term overfat in the above sentence. This phenomenon doesn’t happen in lean beginners for reasons I’m going to explain in a second.
A second situation where this phenomenon occurs readily is folks returning from a layoff. Folks who are previously lean and muscular but who get out of shape (whether deliberately or not) often find that they get back into shape much faster than they did initially: they seem to magically replace fat with muscle. In fact, with the advent of before/after transformation pictures for supplements, this has become a growth industry: people who are already in great shape will deliberately get out of great shape so that they can quickly reattain their previous shape in a short period. Apparently there is huge money in selling such before/after pictures to help move supplements.
But that’s not really what the question was asking which had more to do with this idea: can the body use calories stored in fat cells to support muscle growth, essentially shunting calories from fat to muscle and achieving the holy grail: fat loss with concomitant muscle gain.
And this brings me back to my comment about overfat beginners as I think this explains some of the physiology involved. Please note that I’ve never really seen this topic studied directly and much of what I’m going to write is based on either observation or other known aspects of physiology that I feel tie into the issue.
So consider an individual who is carrying quite a bit of fat and not very much muscle. Your typical overfat beginner trainee. Let’s look a bit at what’s going on physiologically for this person.
One consequence of the excess body fat is a systemic insulin resistance and this is especially true for fat cells. Basically, when fat cells start to get full, they become more resistant to further caloric storage. That is to say: insulin resistance actually develops as an adaptation to obesity and this is one reason that obesity is often associated with things like hyperglycemia, hypertriglyercidemia and hypercholesterolemia; the fat cells get so full that they stop accepting more calories. So instead of being stored, glucose, triglycerides and cholesterol sit in the bloodstream. In that vein, and quite contrary to popular belief, insulin resistance actually predicts weight loss and insulin sensitivity weight gain but that’s another topic for another day.
So we have a situation in overfat folks where fat cells are sort of trying to ‘push calories away’ from the fat cells. That’s point #1.
The second thing to consider is the untrained state and the fact that when people start training, they always make gains in both strength and muscle mass faster. That is, beginners have the potential to gain muscle at a much faster rate (and more easily in terms of the stimulus needed) than someone trained. As well, keep in mind that regular training (both resistance training and cardio) improve muscular insulin sensitivity and nutrient uptake in that one specific tissue (training is probably the most powerful tool in our arsenal to improve nutrient uptake in that specific a fashion). That’s point #2.
So consider the combination: we have a situation with overfat beginners where fat cells are very insulin resistant and essentially trying to push calories away. Now we throw training on that, not only sending a muscle building stimulus via training but increasing nutrient uptake into skeletal muscle through effects on skeletal muscle nutrient uptake/insulin sensitivity.
And what happens under those circumstances is exactly what you’d expect: the body appears to take calories out of fat cells and use them to build muscle. And this is effectively what is happening due to the combination of the above two factors. But the combination of the two is required. A lean beginner won’t see the above because they don’t have the fat to lose/fat energy to shunt to the muscle. And as they get more advanced, the rate of muscle gain slows way down. Again, it’s the combination of overfat and beginner status that comes together here to let some magic occur.
And even there you’re not going to see the body replacing one pound of fat with one pound of muscle for very long. The rates of the different processes are simply too different. What you might see is an initial shift where muscle ‘replaces’ fat due to the calorie shunting effect but invariably it slows down and either muscle gain or (more frequently) fat loss becomes dominant.
Now, having looked at the specific situation of an overfat beginner, let’s look at what happens as one of two things (or both happen): the person becomes leaner and/or achieves a higher training status.
A known adaptation to fat loss is an improvement in insulin sensitivity especially in fat cells. This is part of why fat loss becomes more difficult as folks get leaner as well as why the risk of weight/fat gain is higher at the end of the diet (you’re MORE insulin sensitive). This means that the fat cells not only have less stored fat to give up but it becomes more difficult to get it out of there.
I discussed some of the reasons for this in detail in The Stubborn Fat Solution along with protocols to get around it. But the point is made: as folks get leaner, getting fat out of fat cells becomes more difficult. Some of the hormonal mechanisms involved are also discussed in Calorie Partitioning Part 1 and Calorie Partitioning Part 2.
Furthermore, as folks become better trained, it becomes more difficult to gain muscle under any condition. The training stimulus is higher and the impact of training is lessened.
So the situation that was in place for the overfat beginner has reversed itself in someone who is leaner and/or better trained. Fat cells are no longer insulin resistant and ‘pushing fat calories’ away; quite in fact they are ready to take up excess calories at any time. And since training has a lesser impact on muscle growth, the odds of getting the calorie shunting effect becomes lower and lower approaching nil. Again, that’s on top of all of the hormonal stuff discussed in the above articles (e.g. fat loss and muscle gain requires different hormonal situations).
Which is why a lot of the approaches advocated for ‘gaining muscle while losing fat’ aren’t very effective. In fact, I’d tend to argue that most people’s attempts to achieve the above results in them simply spinning their wheels, making no progress towards either goal. Because invariably they set up a situation where neither training nor diet is optimized for either fat loss or muscle gain. Calories are too high for fat loss and too low to support muscle gains and outside of that one overfat beginner situation, the physiology simply isn’t going to readily allow what they want to happen to happen.
But more specific approaches can be effective in achieving this goal. The Ultimate Diet 2.0 has often generated muscle gains while people dieted to single digit body fat levels (I’d note that the gain in muscle never reaches equality with the fat loss) but it also alternates specific dieting and gaining phases during the week.
Many of the intermittent fasting (IF’ing) approaches do this more acutely and I’d suggest anybody interested go to Martin Berkhan’s Lean Gains site for more information about IF. There are others, things like every other day refeeds (EOD refeeds) which are discussed in some detail in my The Bodyrecomposition Support Forums. But all of those approaches are alternating dieting phases (lowered calories, a net ‘catabolic’ state) with gaining phases (increased calories, a net ‘anabolic’ state).
But none of those approaches generate a muscle gain to equal the fat loss, at best they generate a small muscle gain in the face of a much larger fat loss (e.g. someone might lose a lot of fat while gaining a pound or two of muscle or what have you). But for the non-beginner/non-returning from a layoff trainee that’s about the best you’re going to get. Potential rates of muscle gain are never going to approach the potential rate of fat loss once folks are past the beginner stage. Even in the beginner stage, it’s generally always easier to lose fat much faster than you can gain muscle.
So the idea of replacing every pound of lost fat with exactly one pound of muscle will be essentially impossible for the intermediate/advanced trainee. There’s simply not enough fat/the fat cells dont want to ‘give up their calories’ and the ability to stimulate rapid muscle gains isn’t there any more.
A followup question might be what about fatter but more advanced trainees. Certainly in that situation, fat cell insulin sensitivity/etc. can approach what is occurring with the overfat beginner but there is still the issue of rate of muscle gain being drastically slowed. It’s probably possible briefly at the start of the diet to get some caloric shunting but it’s never going to approach a 1:1 gain in muscle with fat loss; the potential rate of fat loss (1-2 lbs/week) to rates of muscle gain (0.5 lbs/week if you’re lucky) simply doesn’t exist.
As a final comment, I can say without hesitation that someone will post in the comments that they managed to achieve the above results in some form or fashion. And while there are always going to be exceptions to any generality, that doesn’t tend to disprove the generality. And generally speaking, the above is what happens in the real world.
- Insulin Resistance and Fat Loss
- Reducing Body Fat Percentage by Gaining Muscle – Q&A
- Size of Deficit and Muscle Loss
- Low Body Fat in Women, Stubborn Low Back Fat, and Skinny Fat Training
- Body Composition – Calculations