Improving Body Composition: Optimizing Fat Loss & Muscle Building

L.J. Walker
Written By: L.J. Walker
December 5th, 2013
Updated: June 13th, 2020
63.8K Reads
This article provides specific advice on how to approach the fat loss and muscle building process for individuals currently carrying around some unwanted body fat.

Preamble on improving body composition

The goal of most any individual in the gym is to improve their body composition. The conundrum is that improving body composition is a give and take process. For years people have argued over the idea that you cannot simultaneously lose fat and build muscle since that would essentially require mutually exclusive energy intakes (i.e. you can’t ingest a surplus of calories and be in an energetic deficit and vice versa).

This is why the “traditional” approach for many gym-goers looking to improve their body composition is to alternate between periods of building muscle mass and losing fat; colloquially, people usually refer to these timeframes as “bulking” and “cutting”, respectively.

So one way to think of the overall process is like it’s a see-saw between building muscle and losing fat—if you want to increase one then the other will have to decrease. This is probably the greatest conundrum physique competitors have dabbled over ever since they set foot in the iron asylum; alas, without the use of pharmacological doses of PEDs (and even then), it is an exercise in futility to try and concurrently optimize both muscle hypertrophy and fat loss (unless you intend to overcome thermodynamic laws, which I invite you to refute). The other option is to be in a “maintaining” phase (neither building/losing muscle nor losing/gaining fat).

Now when we apply the above predicament to individuals who are already in a state of being overweight, it seems intuitive to work on losing fat first and foremost. While this may be proper in some circumstances, it’s not always the ideal way to go about it and some overweight individuals can actually stand to benefit from working on building muscle before trying to shed the extra flab.

Given this, this guide will cover the possible approaches to improving body composition and apply these protocols to overweight (or even obese) individuals. We will also talk briefly about what exactly body composition is, some of the physiology behind losing fat and building muscle, and the necessity of things like cardiovascular training, weight training, and proper nutrition.

Build Muscle

What is body composition and how does one improve it?

In the fitness/bodybuilding sense, body composition is the percentage of fat tissue (in percentage) that accounts for one’s overall body mass (hence some people may just interchange the terms “composition” and “fat”). Seems pretty simple, but to improve one’s composition is where it gets a bit trickier.

One thing most people seem to skip right over when they set a new physique/fitness goal is the fact that bodyweight alone is not a sufficient measurement for progress. There are few scenarios where someone’s only goal should be to lose or gain weight just for the sake of seeing a quantitative change on the scale. It is rather more pertinent to focus on improving one’s body composition, regardless of what your overall body mass is.

In an ideal world, we would to concomitantly optimize fat burning and muscle building. Unfortunately, as noted before, these two goals are theoretically mutually exclusive at any given moment. However, this does not mean you can’t improve your body composition at any given time.

Improving your body composition simply entails increasing your ratio of muscle to fat tissue, respectively (i.e. lowering your body fat percentage). So for example, if we take Mr. Shredded and add 5lbs of muscle to his frame while only adding, say, 2lbs of fat, we have just improved his body composition. Likewise, if Mr. Shredded was able to shed off 5lbs of fat and only lose 1lb of muscle mass he again has improved his body composition.

So to reiterate, we either want to maximize muscle hypertrophy (while limiting fat gain) or maximize fat burning (while limiting muscle catabolism/loss). Hopefully these examples make the concept of improving body composition more perceptible.

Optimizing muscle building

When we consider the goal of building muscle tissue, it is useful to understand what comprises a state of muscle anabolism/hypertophication. Fundamentally, it breaks down to what is called the net protein turnover ratio, which is a quantitative measurement of muscle protein synthesis (MPS) versus muscle protein breakdown (MPB).

When MPS is greater than MPB, this is indicative of muscular hypertrophy (e.g. a state of anabolism) and vice versa. A plethora of factors cause this ratio to fluctuate, such as exercise, nutrition, disease/immune conditions, gene expression, pharmaceutical agents (e.g. PEDs), over-the-counter supplements, etc.

So in order to optimize/maximize muscle building, we ideally want to maintain a higher rate of MPS than MPB (thus the muscle protein turnover ratio is in favor of anabolism). Easy enough, right? Well, not too fast there Mr. Muscles, for muscle protein synthesis is tightly regulated via a protein encoded by the FRAP1 gene in humans called the mammalian target of rapamycin (mTOR). (1)

The mTOR protein itself acts as the backbone to mTOR protein complexes (e.g. mTORC1 and mTORC2) that activate protein synthesis when necessary cellular conditions are met (and ultimately induces cellular growth and proliferation). (2) As noted earlier, regulation of protein synthesis pathways is highly complex (and extends beyond the premise of this guide), but it’s still worthwhile to have this rudimentary knowledge of how muscle cells actually grow.

The activity of mTOR protein complexes is dependent upon the cell’s energetic state, circulating growth factors and hormones (especially insulin), nutrient availability, and oxidative stress. Given this, the goal for maximizing/optimizing muscle building is to augment these factors so as to up-regulate MPS.

Muscle Building

Optimizing fat loss

On the fat loss side of things, the mechanisms conducive to increasing fat burning are more or less directly antagonistic to those mechanisms involved in muscle building (and vice versa). Fat loss is largely regulated by the enzyme adenosine monophosphate-activated protein kinase (AMPk), a trimeric protein expressed throughout many tissues in the body.

You’re likely aware that adenosine triphosphate (ATP) is the energy currency of the cell and the breakdown of ATP forms adenosine diphosphate (ADP) and free energy. Physiology lingo aside, AMPk is activated when the cell is in a state of energy deprivation (e.g. the ATP: ADP ratio drops). This occurs during times of nutrient (specifically glucose) deprivation, ischemia (lack of blood supply to an organ), exercise,  and /or use of certain chemicals/drugs.

Conversely, things such as eating and excessive glycogen levels inhibit AMPk activity (since the ATP: ADP ratio is elevated).

Why does this all matter in the grand scheme of fat loss? Well, frankly, AMPk increases lipolysis, enhances fatty acid oxidation, improves glucose uptake into muscle tissue, and inhibits lipogenesis. (3) In essence, it is the “metabolic switch” for burning fat.

AMPk and mTOR: A give-and-take relationship

So now we understand the importance of mTOR and AMPk when it comes to improving body composition, but the issue is that they are operated by antagonistic mechanisms. Thus, while AMPk is great for “turning on” fat burning, it is also an inhibitor of mTOR (and thus, muscle protein synthesis). (4) Conversely, mTOR reciprocates by inhibiting AMPk, so when MPS is activated fat burning is inhibited.

If you think about it rationally, this shouldn’t come as a surprise since cellular energy levels can only be sufficient or depleted, with regards to the ATP: ADP ratio, at any given moment. While this is a simplistic way of describing these pathways, it still provides an idea of why you can’t have your cake and it eat it too, so to speak, when it comes to fat burning and muscle building.

However, this is not to say you can’t alternate between these two cell conditions, and in fact that’s what certain things like intermittent fasting, re-feeding protocols and yo-yo dieting are based upon. Theoretically, for improving body composition, it would be best to give each of these pathways (AMPk/mTOR) sufficient stimulation/activation, even if it’s only intermittently. Thus we use the analogy of these two pathways having a give-and-take relationship and acting like a see-saw.

So where should an overweight (over-fat) individual start?

While there will always be individualistic variables at play when it comes to the “perfect plan” for overweight individuals, there are still some general tips to consider when improving body composition is the primary goal. “Overweight” is a somewhat misleading term since it doesn’t necessarily mean someone is “over-fat”, so this is more directed towards individuals with a high body-fat percentage (especially those in the 20+% tier).

You will need to assess yourself honestly/objectively and decide whether or not you have a decent base of muscle mass to work with or if you need to develop that base first. Some larger people may possess an appreciable amount of muscle mass but are also over-fat (think of the “traditional” heavyweight powerlifter), while others may be over-fat and lack significant muscle mass.

Concentration Curl

Creating metabolic “wiggle room”

The main prerequisite when it comes to improving one’s body composition is to elevate metabolic rate as much as possible. One way to think of this is that you want to first “expand” your metabolism so you have room to work with and reduce calorie intake from. There are several factors that help “expand” your metabolism, but the main one we will focus on is building more muscle (since muscle tissue is more metabolically demanding than adipose tissue).

Intuitively, the greater your “starting” metabolic rate is, the more efficient the process of improving body composition becomes. The main reason we want to expand your metabolic capacity early on is because long-term energy restriction will slowly lower metabolic rate and eventually you will reach a plateau where fat loss just won’t budge anymore.

Therefore, it is imperative to get your metabolism “healthy” (so to speak) before you try shedding off extra flab. This is not to say you absolutely can’t lose fat without first working on building muscle mass, but just that it will be much more efficient in the long run and make the process much more bearable physically and psychologically.

How to approach body recomposition when you are overweight

Case 1: over-fat but has decent amount of muscle mass

In the case of the over-fat but musclebound individual, it may be more appropriate to focus on shedding the extra flab first and mix in intermittent periods of maintaining and/or bulking. Since these individuals have a decent amount of muscle mass they have a greater metabolic capacity to taper down from; essentially, these individuals have more “wiggle room” to work with when it comes to cutting calories.

As noted before, metabolic rate slows as one remains in an energetic deficit, so by interspersing brief periods of caloric surplus you can avoid fat-loss plateaus (and enjoy the extra nourishment for a while). This is where you will need to assess your progress and adapt as you go on.

Some people may be able to achieve consistent fat loss for months before ever needing a “re-feeding” period, while others may stall within a few weeks. Since I can’t provide a one-size-fits-all protocol, here’s just a sample diet scheme for someone in this category looking to improve body composition:

  • Phase 1—“Cut” with a goal of roughly 5% bodyweight loss per month or until your weight loss stalls. A good starting point to achieve this is by cutting 500 calories from your maintenance energy expenditure (which can be calculated here:
  • Phase 2—once fat/weight loss stalls, increase calories back to maintenance or possibly a slight surplus for 1-2 weeks. You may notice some weight increases during this period but don’t panic.
  • Phase 3—Resume “cutting” again as you were in phase 1. Repeat phases 1 and 2 until you have reached your goal body-fat percentage/body composition.

Cable Front Laterals

Case 2: over-fat and lacks significant muscle mass

On the contrary, if someone lacks muscle mass and is over-fat, they are in a bind metabolically since their energy expenditure is already likely rather low and they will have to severely cut calories just to lose a slight amount of weight. Moreover, when calorie content is severely limited in these instances, most of the weight loss will just be muscle mass anyway, essentially lowering your bodyweight but not your body-fat. This generally manifests itself into the dreaded “skinny-fat” syndrome, which is quite the predicament to get out of.

Therefore, if you are in this category it is generally wise to consider eating either at maintenance calorie levels or in a “slight” deficit and focusing on resistance training. Most people probably think this is inane to recommend an obese/over-fat individual to not focus on weight loss and doing tons of cardio, but I would argue that by focusing on building and maintaining some decent muscle mass/strength at this point the individual will be setup for much more efficient fat loss in the long run. Again, don’t be blinded by short-term results.

Also bear in mind, I’m not saying these individuals need to go full blown “cutting” mode, starve themselves and pretend it’s for the best. If you give yourself time, remain consistent, and focus on resistance training, even a slight calorie deficit (or eating at maintenance) will be conducive to improving body composition since you will slowly lose fat and maintain strength and muscle.

This is not to say that cardio shouldn’t be implemented either, just that it is not necessary (nor useful) to be doing hours of daily cardio unless you just want to sacrifice mostly muscle mass (which you already have very little of if you’re in this category).

As noted above, there is no one-size-fits-all scheme for individuals in this category, so here is a sample (this is not all too different from that of Case 1 individuals):

  • Phase 1—“Cut/Maintain” with a goal of slight reduction in weight each week (e.g. .5-1lb week). A good starting point to achieve this is by eating around maintenance energy expenditure (use calculator provided earlier) and making sure you are active (and focusing on resistance training). You may also opt to cut a few hundred calories from your maintenance intake if you’re not seeing much weight loss each week.
  • Phase 2—Same as Case 1; once fat/weight loss stalls (or you experience notable decreases in strength), increase calories back to maintenance or possibly a slight surplus for 1-2 weeks. You may notice some weight increases during this period but don’t panic.
  • Phase 3—Same as Case 1; resume “cutting” again as you were in phase 1. Repeat phases 1 and 2 until you have reached your goal body-fat percentage/body composition.

The case for overweight teens

The predicament of being over-fat as a teenager can be quite a tough spot. These individuals usually do more harm than good to their body by focusing on extreme calorie restriction and cardio. If you’re a teenager and over-fat, here’s the reality: you need to understand what made you obese and change those habits.

The issue with extreme weight loss during crucial developmental periods is the havoc that can be wreaked on your endocrine/metabolic health. Many over-fat teens take things too far and set themselves up for a myriad of health complications just for the sake of lowering the number on the scale.

So as above, teens that are over-fat would likely benefit more from the recommendations for “Case 2” and really emphasize correcting unhealthy habits and focusing on resistance training/building strength.

What about macronutrient ratios?

While there may be some merit to micromanaging your macronutrient intake down to the last gram, over-fat individuals need to first and foremost just focus on eating less, period. That being said, it is probably best in the long-run for most over-fat individuals to focus on balancing their intake of fats, proteins and carbohydrates rather than adhering to extreme measures like keto dieting.

Reason being is that a focus on moderation of all macronutrients and calorie control not only gives the individual more freedom while dieting, but it doesn’t “restrict” them either or engrain the idea in their head that certain nutrients/foods are “off limits”.

Final word

Many people don’t stick with a plan because they get upset with the short-term results (or lack thereof) and completely forget that improving health/fitness and body composition is a lifelong endeavor. You can’t rush the process; it will take a concerted effort and consistency on your behalf to achieve the body and level of fitness you desire. If at any point you feel like you’re not making progress, take a step back, assess your long-term goals, and make any necessary changes to your current habits to continue your journey.

Again, you need to understand what made you obese/over-fat and change those habits. Just doing that and implementing a sound diet and exercise regimen will ameliorate many of the health maladies that come with the territory of being obese. Don’t make this more complicated than it has to be.


1. Tokunaga C, Yoshino K, Yonezawa K (2004). "mTOR integrates amino acid- and energy-sensing pathways". Biochem Biophys Res Commun 313 (2): 443–6. doi:10.1016/j.bbrc.2003.07.019. PMID 14684182.

2. Wullschleger S, Loewith R, Hall MN (February 2006). "TOR signaling in growth and metabolism". Cell 124 (3): 471–84. doi:10.1016/j.cell.2006.01.016. PMID 16469695.

3. Ruderman NB et. al. Minireview: Malonyl CoA, AMP-activated protein kinase, and adiposity. Endocrinology (2003) 144: 5166-5171.

4. Bolster, DR. AMP-activated protein kinase suppresses protein synthesis in rat skeletal muscle through down-regulated mammalian target of rapomyacin (mTOR) signaling. J Biol Chem (2002) 277: 23977-23980.

Laila Garcia
Posted on: Wed, 09/01/2021 - 10:02

Is it okey for lactating mom to do some exercises like this

M&S Team Badge
Posted on: Mon, 09/13/2021 - 20:33

Hi, Laila. That is actually a question that would be best answered by your personal physician.

Posted on: Mon, 11/16/2015 - 03:37

thanks walker

Willie Mac
Posted on: Sun, 01/04/2015 - 15:51

Thanks for the great article! It's nice to see an article aimed at easy gainers/hard losers for a change.

Drek Zoolander
Posted on: Mon, 12/30/2013 - 05:16

after doing crossfit for the past 12 months I started at a regular gym in Sept 2013. When I joined the gym I decided to have a body composition check and I also started the anabolic diet which I had read up on.

3 months have passed and another body composition check showed a 5kg fat loss with a 1.7kg muscle gain (23.3% body fat to 18.9%).

My training doesn't change between cutting and bulking. My training is pretty much 6-12 reps/set combined with HIT (hr 160-175 bpm) between sets and it seems I am stimulating both muscle growth and fat loss.

Is this just because I am carrying excess bodyfat and because I am following a high fat moderate protein low carb diet I am using my body fat as energy??

Posted on: Fri, 12/06/2013 - 16:12

There is a nice article, but do you have any way to read in spanish? ! That's will be amazing !

May Palmer
Posted on: Thu, 12/05/2013 - 18:32

Great Article L.J.!! Your article is jam packed with lots of great information and advice. In fact, I am one of those individuals who is in the Case 1: over-fat but has decent amount of muscle mass category. I started cutting back on both calories and cardio a few weeks ago (I still do Total Body Strength Training 3 X a week with some targeting of 'problem areas' on my off days) and am finally seeing the results I've longed for. My body composition has vastly improved! Thanks for your article! Keep em' comin'!

Posted on: Thu, 12/05/2013 - 16:47

Nice article!