How Many Days Per Week Should Somebody Work Out to Build Muscle & Lose Fat?

There are some of us that want to build muscle. And then there are those of us that want to lose fat. But I’d be shocked to find somebody that wouldn’t want to achieve both of these fitness goals simultaneously. This phenomenon has a name, and it’s called body recomposition. 

There’s no questioning that diet will ultimately be the most important factor behind body recomposition success. That would require an entirely separate article (or a series of separate articles!) in order to emphasize that point. 

However, it’s impossible to build muscle without resistance training, and you risk serious muscle loss pursuing fat loss without resistance training. There needs to be some sort of training stimulus present. In other words, your muscles need a legitimate reason to grow. Your body won’t just grow muscle if it senses it’s not necessary, since skeletal muscle tissue is “metabolically expensive” to manufacture. 

Okay, so we know that resistance training is important. But the question remains “how many days per week should I work out so that I can build muscle and lose fat?

Well, it depends…

When you think about it, asking “How Many Days A Week Should Somebody Workout?” is a very broad question, no matter what the person’s specific fitness goal is. Both physiological and lifestyle factors play a significant role when determining how often somebody should workout. Some examples of each type of factor are listed in the table below:

Frequency is Just One Part of the Equation

When somebody asks how often something should be done, this refers to the frequency of that event. Merriam-Webster defines frequency as:

“The number of occurrences of a repeating event per unit of time” [1].

Training frequency is just one of the many components that make up an exercise program. Some other elements of an exercise program that should be taken into consideration include: 

Rest intervals, weightlifting velocity, and type of gym equipment used are also other variables to think about. 

This list is by no means exhaustive. But hopefully now you understand that yes, while training frequency is an important factor for success in your training, it’s just one of many factors to think about. 

Untrained Populations

Many studies observing the effects of training frequency on aspects of body composition and strength primarily emphasize untrained and inexperienced populations. 

One study in middle-aged women compared 2 different resistance training programs; one of which was 3 days per week and the other was 4 days per week [2]. The 3 days per week group completed each session on non-consecutive days, while the 4 days per week group completed each session on consecutive days. The overall amount of volume performed by each group was the same. Over the course of 8 weeks, women in both groups significantly increased their levels of muscle mass, with no statistically significant differences between the groups. 

In a 6-week resistance training program with both men and women, one group trained 2 days per week and the other group trained 3 days per week [3]. The researchers ensured that both groups were performing the same amount of volume. Both groups (which were each comprised of both men and women) equally increased their muscle mass and strength, and just like the aforementioned study, there was no statistically significant differences between the 2 groups in terms of overall muscle mass and strength gained.

Frequency Doesn’t Just Mean Number of Sessions

Frequency is often thought of as simply the number of training sessions performed during a one-week period.

However, it’s more valuable to think of frequency as a measure of how many times per week specific muscle groups are being trained.

This ensures that your training plan is well-rounded and all encompassing. It helps to avoid asymmetries and imbalances, both from an aesthetic and a functional perspective. 

One study from McMaster University in Ontario, Canada implemented this concept into their study design. They recruited 30 college aged women (none of whom had formal resistance training experience) and divided them into 3 groups; control group (no exercise), whole routine, and split routine [4]. So, what does whole-body and split routine mean exactly?

Exercise routines are structured more broadly into one of two ways; whole-body routines, where the individual performs exercises for all muscle groups in one single session, or split routines, where to individual separates the exercises into sections and only performs specific exercises for one section on a particular day (e.g., “upper-body” days and “lower-body” days). 

This exercise program had each individual train each muscle group twice per week, regardless of the experimental group they were placed in. The only difference here was that one group performed 2 whole-body sessions per week and the other group performed 4 split sessions per week. So, while the relative frequency for each muscle group was the same between both groups (number of sets performed for each muscle group), the absolute frequency (total number of exercise sessions) was not.

Ultimately, the study found that whole-body and split training routines produced similar training responses (accrual of lean muscle tissue and decreased body fat %) over the course of roughly 5 months of training (20 weeks). 

White bars indicate the time period before the 20-week training program started and the black bars represent the time period after the 20-week training program ended. The asterisks (*) indicates that there is a statistically significant difference compared to where that group started from, which in this case was all the groups with the obvious exception here being the control group, who did not perform any exercise throughout the entire study period. 

Notice in the figures above how both the “whole” and “split” groups experienced similar gains in lean tissue mass and decreases in body fat percentage, relative to where they started from. 

Trained Populations

The amount of data available in trained, experienced individuals is more limited compared to untrained individuals. Fortunately, though, research in this area for trained individuals has increased more recently. 

Similar to the design of the study we just discussed with the 30 college-aged women, a study conducted in 2019 recruited men with at least 3 years of training experience. These men were placed into one of two groups; “low-frequency” (split routine, each muscle group trained 1x/week) and “high-frequency” (whole-body routine, each muscle group trained every session). 

What makes this study particularly interesting is that both groups trained for same number of days (5 days, Monday-Friday for 8 weeks), with the only difference being the number of days they trained a particular muscle group. Volume was also equated between the two groups.

Similar to what was observed in many of the studies that examined untrained populations, both exercise frequencies were effective in increasing strength and muscle growth [5]. This result was supported by another research group that replicated this study design, with the only difference being that the latter research group included both men and women as subjects [6]. 

Untrained vs. Trained Populations

A meta-analysis in research is a type of review paper that aggregates multiple studies on a topic and attempts to reach a statistical conclusion based on all the data gathered. One of these types of papers was conducted on the effects of various training variables (one of which, of course, happened to be frequency) on gains in strength [7]. 

 The researchers discovered that those who were untrained (no prior formal lifting experience) saw improvements in strength as they increased the number of times they trained each muscle group per week, up to 3 days per week. For those who had prior formal lifting experience, training a muscle group 2 times per week elicited the greatest results.

Noticing a Trend Here?

If you’ve been paying close attention, you may have noticed that all the studies we went over in this article here today have one thing in common. 

It’s that they came to the general consensus that frequency didn’t make much of a difference in the amount of muscle gained or fat lost. What mattered the most was the amount of volume that was being performed. As long as volume was equated between groups, the outcomes were very similar. 

In fact, equating for volume is a sign of a good research design. In order to illustrate this point, one of the current leaders in exercise science research Brad Schoenfeld conducted a meta-analysis that examined the effects of frequency on muscle growth (hypertrophy). He conducted analyses on studies that equated for volume as well as those that didn’t [8]. 

For the volume-equated studies, no significant difference in strength and body composition between those who performed low-frequency or high-frequency exercise programs. Studies that did not factor in the equalization of volume between groups tended to favor higher frequency exercise programs compared to lower frequencies. While this effect was statistically significant, it was still relatively modest. 

 
This plot illustrates all of the volume-equated studies, along with the body parts that were examined for changes in muscle size. 

As you can see, a large majority of the lines are centered around the “0” line on the x-axis. This indicates that frequency was irrelevant to the amount of muscle mass gained. As long as volume was accounted for and equal between groups, individuals experienced similar benefits regardless of the number of times they exercised per week.

Practical Takeaways

This article has provided you with interpretations on the highest quality data that’s currently available at this moment in time regarding training frequency. But what is that all worth if you don’t have something practical to take away from this?

At the end of the day, the number of days you should workout per week in order to build muscle and lose fat depends on your schedule and lifestyle. Performing 2-3 full-body workouts per week where you’re targeting each muscle group at least once per week (but preferably twice) is sufficient to see the benefits you’re looking for. Just keep in mind that you might have to spend a little more time in the gym during each of your sessions compared to somebody who goes to the gym 3+ days per week, since those who’s schedules allow for higher frequencies have the ability to space out the amount of “work” they have to perform.

There’s not really a right or wrong answer here. While some people don’t have time to go to the gym as often as others, some people simply prefer shorter duration workouts as opposed to lengthier ones. And that’s completely okay. As long as the amount of volume in your program is sufficient to see progress, it’s then just a matter of personal preference. 

If your fitness goals place a greater emphasis towards fat loss, then it might be worth it to you to tack on a short HIIT (high intensity interval training) cardio session at the end of your workout in order to be as efficient with your time as possible. It doesn’t have to be only HIIT cardio of course. You can also perform a lower impact activity like jogging or walking on an incline on a treadmill. Just remember that lower intensity cardio will require more time to complete in order to match the volume of shorter duration, higher intensity cardio. 

Another option is to perform your cardio on a day that’s separate from your weight training sessions if your schedule allows or if you simply prefer to do it that way instead. It’s important to remember that you’re not under any sort of obligation to perform cardio. Some people may have jobs and lifestyles that are relatively active as it is, therefore rendering cardio as unnecessary additional activity. Think of weight training as the primary foundation that’s necessary to build muscle and burn fat, and cardio simply as a supplement to assist in that process. 

The information presented here to you today is not meant to act as the “end all, be all” and you may find that a different amount of training frequency works better for you compared to somebody else. It may take some trail-and-error before finding the amount of training frequency that works for you, so don’t be afraid to experiment! 

References

1. Frequency, in Merriam-Webster. Merriam-Webster.com dictionary.

2. Benton, M.J., et al., Short-Term Effects of Resistance Training Frequency on Body Composition and Strength in Middle-Aged Women. The Journal of Strength & Conditioning Research, 2011. 25(11): p. 3142-3149.

3. CANDOW, D.G. and D.G. BURKE, EFFECT OF SHORT-TERM EQUAL-VOLUME RESISTANCE TRAINING WITH DIFFERENT WORKOUT FREQUENCY ON MUSCLE MASS AND STRENGTH IN UNTRAINED MEN AND WOMEN. The Journal of Strength & Conditioning Research, 2007. 21(1): p. 204-207.

4. Calder, A.W., et al., Comparison of whole and split weight training routines in young women. Can J Appl Physiol, 1994. 19(2): p. 185-99.

5. Gomes, G.K., et al., High-Frequency Resistance Training Is Not More Effective Than Low-Frequency Resistance Training in Increasing Muscle Mass and Strength in Well-Trained Men. J Strength Cond Res, 2019. 33 Suppl 1: p. S130-s139.

6. Thomas, M.H. and S.P. Burns, Increasing Lean Mass and Strength: A Comparison of High Frequency Strength Training to Lower Frequency Strength Training. Int J Exerc Sci, 2016. 9(2): p. 159-167.

7. RHEA, M.R., et al., A Meta-analysis to Determine the Dose Response for Strength Development. Medicine & Science in Sports & Exercise, 2003. 35(3): p. 456-464.

8. Schoenfeld, B.J., J. Grgic, and J. Krieger, How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency. J Sports Sci, 2019. 37(11): p. 1286-1295.