Lift weights to lose fat...
Summary
A newly published study has revealed that strength training reduces body fat. This means that in addition to aerobic training and calorie restriction, we now have another tool in our tool kit when it comes to reducing body fat- something very exciting!
Full article
Earlier last week, the Sports Medicine journal published a study that is, as exercise professionals, music to our ears.
A team of researchers from the University of New South Wales (including one of our exercise physiologists here at Aevum, Brandon), have found that strength training, on its own, can reduce body fat.
Although we knew previously that strength training was amazing for our health for a variety of reasons, we were unsure of its effect on fat mass. Similarly, although we knew that aerobic training (e.g. walking, running, cycling) and dieting (i.e. calorie restriction) were both proven and effective ways at reducing fat mass, we were unsure whether the story was the same for strength training.
This study is the first of its kind to definitively confirm that strength training (i.e. lifting weights) is able to reduce fat mass. Specifically, it found that strength training reduces body fat percentage, body fat mass and visceral fat mass.
Body fat percentage
Body fat percentage is the proportion of total body mass that is fat tissue. Anything that is not fat tissue is considered lean body mass (e.g. muscle, bone). For reference, the typical healthy body fat percentage range for a female is 20-30% and the typical healthy range for a male is 12-20%.
The reduction in body fat percentage was perhaps the most unsurprising finding of the study. This is because it is well established that strength training is likely to increase muscle mass. Since muscle mass is a constituent of lean body mass, its accrual increases lean body mass. When the proportion of lean body mass increases, it means that the proportion of body fat mass decreases. This results in a reduction in body fat percentage.
The study found that strength training reduces body fat percentage by an average of -1.46% (it doesn’t sound like much, but it’s quite a lot!) However, the study didn’t say for certain whether the reduction was due to the mechanism just described, or if strength training actually reduces fat itself (regardless of whether lean body mass increases). With that said, given the paragraph to follow, it is likely a combination of the two.
Body fat mass
It was expected that this problem would arise; how do we know whether the reduction in body fat percentage is due to actual fat loss, or if it’s just due to a relative increase in lean mass (muscle)? To combat this, we examined the effect of strength training on body fat mass itself.
It was found that strength training reduces body fat mass by an average of -0.55kg (again, it doesn’t sound like much, but this is about the equivalent to a block of butter!). This means that strength training, by itself, reduces fat, regardless of whether you build any muscle.
Visceral fat
Visceral fat is fat that surrounds our organs. It is ‘bad’ fat, due to its association with many major diseases. Consequently, anything that has the potential to reduce visceral fat is a really, really good thing.
The study found that strength training reduces visceral fat. Huge! Due to a bit of a research nuance, though, it’s hard to express just how much visceral fat was reduced by (in terms of kilograms/percentage), but it was found to be a moderate reduction effect (so, not heaps, but not a little bit).
What type of study was it?
The type of study is called a ‘Systematic Review and Meta-Analysis’, and involves two main processes.
The ‘Systematic Review’ part: Searching for a whole bunch of research papers relating to a specific topic (in this case, the topic was strength training’s effect on body fat), collating them, and then creating a big summary of what they all say about the topic.
The ‘Meta-Analysis’ part: Unfortunately, we can’t just leave the systematic review on its own and exclaim that its conclusions are scientifically valid. This is because it is hard to standardise the results found by each individual paper. As a result, some hairy statistics must be applied to all of the collected data in the systematic review to quantify the strength of and validate the findings.
Fortunately, it was statistically proven that strength training does indeed reduce body fat.
But what about cardio and dieting? How effective is strength training compared to them?
The amazing news is that strength training is almost as good, if not as good, as aerobic training and caloric restriction when it comes to fat loss.
As with anything, though, balance is key. For optimal fat reduction and overall health, it is likely best to incorporate all three modes.
Regardless, it’s still good to know we have another tool in our tool kit when it comes to reducing body fat (especially if you aren’t the biggest fan of cardio or dieting!).
How much strength training is required to lose fat?
At least four weeks of a whole-body strength training program is required to see the degree of fat reduction found in the study. As per the regular resistance/strength training guidelines, however, you still need to strength train for at least 2 sessions per week, and it needs to be at a relatively high intensity (i.e. lifting pretty heavy!).
The important consideration with the study
As with most scientific studies, this study was population specific. In this case, the population studied was ‘apparently-healthy’ adults. This means that studies were only included if they examined the effect of resistance training on fat mass in adults who had no diagnosis of any disease or illness, had no current or past injury, were not doing other training or dieting, and weren’t elite athletes.
This isn’t to say that strength training doesn’t lead to reductions in fat if you aren’t ‘healthy,’ it just means that we are not yet sure if it does. Further studies are required to determine if strength training has the same effect in other populations, such as individuals who have diabetes or high blood pressure.
Fat loss is just one of the many benefits of strength training
As mentioned, strength training is a remarkable tool, and learning that it reduces body fat is just the icing on the cake. To name a few, strength training may increase muscle strength, improve blood sugar control, improve cardiovascular health, increase bone density, assist in the management of pain, and improve mental health.
As a result, strength training should be incorporated into nearly everyone’s exercise routine, regardless of whether or not you are looking to burn some fat.
If you are looking for further guidance and would like to speak to one of our exercise physiologists, please do not hesitate to get in touch via the contact details below.
Aevum Physiotherapy
Phone: 02 8544 3231 (Kirrawee) or 02 4294 9990 (Helensburgh)
Email: info@aevumhealth.com.au
Brandon Coorie, AEP