The Lightweight High Reps Myth

high reps myth

Table of Contents

You must do high reps / light weights

The reason why I chose to address this myth first is because it’s been around for TOO long! Fortunately, many fitness related myths were debunked over the past few years, however, for some odd reason, this one still lives. Ironically, it is also one of the worst things you can if you are serious about changing your body composition and achieving a ripped physique.

TL;DR Version

  • Switching to a light-weights-high-reps program will increase the risk of losing muscle mass.
  • L.W.H.R. approach is time consuming.
  • Losing muscle mass will yield unfavorable changes in body composition.
  • L.W.H.R. is a “bro myth”.
  • Heavy weights/high intensity training will allow you to retain a greater amount of muscle mass.
  • Heavy weights/high intensity will raise EPOC significantly more than L.W.H.R.
  • L.W.H.R. won’t provide a strong enough stimulus to give your body a reason to maintain muscle mass.
  • L.W.H.R. will cause you to lose strength.

The absolute worst thing you can do when transitioning into fat loss mode is to switch to a high-reps only program. I’m sure you’ve heard something like this: “to lose fat, you have to do high reps BRO!”. An intelligently designed training program should have you training in different rep ranges. This is because a smart program will consider whether you are in an energy deficit or surplus, your individual response to strength training, intensity, volume, past and potential injuries, frequency…etc. The truth is you can build muscle and lose fat at any rep ranges, but an important question is which approach is most efficient. Sure, you can build muscle doing body weight exercises, but it won’t be long till your body adapts and your progress slows down which will result in you needing to apply more stress (heavier weights / more resistance) if you want to make more progress. One might argue that when your body adapts you can merely execute the same body weight exercise(s) for higher reps. But, how high is high enough? What are you going to do after you can do 50 pull-ups with your own body weight? Do 70? Realistically, this approach will not yield optimal progress and lifting weights will be inevitable. Moreover, losing fat has nothing to with what rep range you use. Losing weight/fat is a mere result of being in an energy deficit or expending more energy than you consume.
I went a little off track here. Anyway, so why is switching to only high reps counterproductive?

  1. You risk losing a lot of lean muscle mass
  2. Inefficient
  3. You risk losing strength
  4. No direct effect on fat mass


1- The risk of losing lean muscle mass increases significantly

muscle atrophy
The risk of losing lean muscle mass when adopting a light-weights-high-reps approach increases significantly for the following reasons:

  • Lack of stress/stimulus
  • Greater deficit
  • Too much stress

Let’s examine the first reason. The main reason we can build muscle is because our bodies can adapt to stress. The human body only cares about one thing: survival. Since strength training is an excellent form of stress, our body responds by adapting and building muscle to be able to resist future stress. Our bodies perceive stress that’s being imposed upon it as “danger”. So, if you can only do 2 pull ups today, you will most likely be able to do many more the next time you apply the stress on your body (pull ups).
When you switch to a light-weights-high-reps program you significantly decrease the amount of stress that your body is accustomed to handling. Thus, your body has absolutely no reason to keep the muscle mass it had built to combat the higher stress it was being put under. Example: your chest gets bigger due to being able to bench 250 pounds. You start doing lighter weights and do not touch the 250-pounds anytime during your “cut”. Why would your body keep your chest the same size that can handle 250 pounds when it’s not being put under the same pressure anymore? Result? Muscle atrophy.
This is even more true because muscle mass is the most “expensive” type of tissue. In other words, muscles require significantly more energy to be built or maintained.

The second problem is that doing higher reps indirectly increases energy expenditure due to doing more work. If your regular training session takes 1 hours to complete, switching to ultra-high reps will almost always take double the time. This is counterproductive if you are already in an energy deficit. Why? Because it’ll put you at an even greater deficit which also increases the risk of losing muscle mass. So, for example, if you have designed your diet plan and decided that being in a 500-calorie deficit is most optimal for you, doing significantly higher reps might put you at a greater calorie deficit.
The greater the caloric deficit, the greater the risk of losing muscle mass. Yes, the number on the scale may decrease faster, but chances are you are also losing more muscle mass. There is a threshold of how fast you can lose fat without losing muscle mass. Weight is not indicative of body composition. A decrease or increase in “weight” could be a result of increase/decrease in fat mass, muscle mass, water, food in G.I. tract…etc. So, resorting to just what the scale says is a recipe for failure.

A third issue that arises with high reps is that you can easily end up doing too much volume. This may seem contradictory to what I just said two paragraphs ago, but read along. So, ditching heavy weights for lighter weights and higher reps can significantly decrease the stress applied on your body and muscles which will result in muscle atrophy (your body has new use of energy-demanding tissue that’s not being used). On the other hand, there is a certain threshold of how much work each person can handle. Even under normal circumstances, if your training intensity and volume are not optimized and you continue doing tons of work, you will eventually burn out and lose muscle mass or at least make sub-optimal gains. The risk is even greater when you are at a caloric deficit since your recovery isn’t be up to par. Thus, your training volume and intensity must be optimized accordingly. So, if you consistently do high reps, you will also be doing too much volume, and once again, you risk losing more muscle mass. “High reps” are fine as part of a structurally-balanced training program, but they shouldn’t be the only tool in your arsenal.


Why would you want to spend 2 hours at the gym when you can do “less” work in a shorter time and get better results? Doing very high reps is often time consuming due to the high amount of volume per session, gym logistics, machines being occupied…etc. Thus, providing the right stimulus through heavier weights is time efficient and will yield higher retention of muscle mass. Heavy weights could be defined as 70-90% of your 1RM.

3-You risk losing strength

Strength is a by-product of both neural and muscular drive. The central nervous system and muscles are both recruited during resistance training. Resistance training not only results in muscle hypertrophy, but also in neuromuscular adaptations. Meaning, your body adapts to strength training by building muscle and “learning” how to use those muscles by efficiently recruiting neuromuscular drive. Simply, your nervous system learns how to use your muscles better.
Therefore, guess what your body will do when you solely do light weights for high reps? You will lose muscles AND strength! You will lose muscle due to lack of stimulus, and you will strength due to losing muscle and your nervous system losing its neuromuscular adaptation. Which is why taking some time off the gym yields loss in strength.

4-No direct effect on fat mass

Just because you sweat excessively and “feel the burn” when doing high reps with light weights doesn’t mean you are burning fat. Regardless of your training style, high reps or low reps have no direct effect on fat loss. However, exercise intensity does indeed affect fat oxidation rate. Also, losing fat is a result of optimal nutrition and training plans. If you are timing your food intake properly, consuming the right amounts of macros, consume mostly high quality whole foods and train hard and smart, you will maximize fat loss AND even build muscle -more on this later-. For instance, if you have a well-structured customized training plan that’s tailored to your own genetics, lifestyle, goals…etc. while taking into consideration volume, intensity and frequency, you should be able to recover adequately, gain muscle, lose fat and increase your strength levels.

NOTE: Since “low weights high reps” is still a form of resistance training, you will still preserve some of your muscle mass. This is because you are still somewhat stimulating your muscles, however, when wanting to retain as much muscle mass as possible and even gain more muscle, a stronger stimulus will be required. So, it could be said that lifting low weights for high reps is still better than being inactive.
Another argument a “bro” may raise is that doing more reps will require burning more calories and thus -theoretically- yield greater fat loss. As I have mentioned a few points ago, there is a limit on how fast you can lose fat without losing muscle. This rate varies from an individual to another. So, when you’re past that ideal fat loss rate, the weight you lose will come from your precious muscle mass. Once again, the greater the deficit the higher the risk of losing muscle. Additionally, an interesting term that’s often associated with low weight for high reps is the “afterburn” effect. Which informally refers to the calories burn post exercise. Though skeptical, I’ll assume the bros are referring to “EPOC”, or excess post-exercise oxygen consumption. Lifting light weights for high reps supposedly increases calorie expenditure significantly more than lifting heavy weights. This is based on simplistic thinking: the more work you do, the more calories you burn. Right? Not exactly. In fact, it’s quite the opposite!
In a study conducted by Thornton and Potteiger (2002), the researchers investigated the effect of two exercise regiments with two different intensities, low and high, on EPOC and energy expenditure. Both programs were adjusted to keep total work equal. High intensity program included 2 sets of 8 reps at 85% of 8RM. Low intensity program included nine exercises for 4 sets of 15 reps at 45% of 8RM. The researchers found that the high intensity program elicited a greater EPOC response (11 calories versus 5.5 calories).
What does this study tell us? Despite doing almost double the number of reps, higher intensity training will elicit a greater “afterburn” effect. Thus, EPOC is influenced by exercise intensity rather than duration. So, save your time and follow a smart training program.

“But, many guys swear by high reps! My friend started doing high reps and he is shredded.”

Perhaps, but many other factors could’ve easily affected their results. Such factors include but are not limited to:

  • Genetic response to strength training
  • Having a significant amount of muscle mass
  • Steroid usage
  • Having low amounts of body fat

Genetic response to training – individuals with good genetics will have an easier time building and retaining muscle mass. This depends on many factors such as nutrient partitioning, quality of diet, sleep quality, stress levels, hormonal levels…etc. Thus, an individual with great genetics will retain more muscle mass than the average Joe when both adopt the low weights high reps approach. However, that person can retain and even build muscle while losing fat which will further improve his body composition and aesthetic look. So, even though the genetically-gifted individual retained a good amount of muscle while dieting, he could’ve achieved a much better body composition had he trained properly. And although he retained a good chunk of muscle mass while dieting, he still probably lost some due to absence of strong consistent stimulus.
Having a significant amount of muscle mass – Your friend might’ve gotten shredded, but this doesn’t mean he didn’t lose muscle in the process. If your friend starts dieting with a great amounts of muscle mass, he will still look great by the time he loses a significant amount of fat to look shredded despite losing muscle mass. Why? Because even though he still lost a considerable amount of muscle mass, he had a good muscular base to make him look good even when he loses some. Had your friend started dieting with less muscle on his frame, he wouldn’t have looked as good as he did.
Steroid usage – It’s no secret that steroids change the equation. Steroids increase hormonal levels to superhuman levels, significantly enhance nutrient partitioning, create an anabolic environment, increase protein synthesis rate…etc. Steroids make it much easier to not only retain but also to gain a significant amount of muscle while dieting. Therefore, it’s not surprising that a “light weights, high reps” bro will retain all his muscle mass on a diet and gain some more.
Having low amounts of body fat – An individual who starts dieting with a tiny amount of fat to lose will look ripped by the time he loses that amount of fat merely because he won’t stay in a caloric deficit for long enough to lose a significant amount of muscle mass. In other words, the shorter the cut, the less muscle you lose. The less time you spend in a deficit, the more muscle mass you will retain. Moral of the story? Don’t dirty bulk!

Bottom Line

If you wish to retain as much muscle as possible while maximizing fat loss, do not resort to solely doing light weights for high reps. Doing so will increase the risk of losing a good chunk of muscle tissue and will result in less fat being lost. Ultimately, you will not achieve the results you had worked hard to achieve. It’s crucial to note that total volume and intensity also apply in this case. Thus, an intelligently designed program that implements a variety of rep ranges will provide the optimal amount of volume and stimulus needed to retain and even build muscle mass while maximizing fat loss. Also, you can build muscle, gain strength, and increase muscular endurance at all rep ranges, however, when comparing a high-reps-only program to a low-reps-only program, the low-reps-only program will elicit more size, strength, and endurance while saving you plenty of time.

Evans, W. J. (2010, April). Skeletal muscle loss: cachexia, sarcopenia, and inactivity. Retrieved from American Journal of Clinical Nutrition:
Helms ER, F. P. (2015, Mar). Recommendations for natural bodybuilding contest preparation: resistance and cardiovascular training. Retrieved from PubMed:
Thornton MK, P. J. (2002, April). Effects of resistance exercise bouts of different intensities but equal work on EPOC. Retrieved from
Paddon-Jones, D. (2006, August). Interplay of Stress and Physical Inactivity on Muscle Loss: Nutritional Countermeasures. Retrieved from The Jounal of Nutrition:
Holm L, et al, Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity, Journal of Applied Physiology, Nov 2008, 105:1454-1461



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