April 21, 2017

Within the fitness realm, there is a handful of enduring and guiding principles that everyone just seems to automatically know shortly after stepping into the gym for the first time. Some of these are time-tested, proven and trustworthy.

Most of these axioms, however, are completely false and need to just die already. One of the most persistent and pervasive of all of these concepts is this: To lose fat, use light weights with high reps. This is often recited in conjunction with the other half of the false equation: To bulk, lift heavy weights for a few reps.

As you may have gathered from the tone of this article, that is entirely wrong. In fact, if you're struggling to lose fat by swinging around the lightest weights you can find, you're actually doing yourself a huge disservice. The reality is that heavy lifting is a much better way to shred fat.


To really understand the advantage that heavy lifting has over it's lighter counterpart, we need to compare both the immediate and long-term impacts of both forms of training.

Just To Be Clear

But what are we talking about when we say “heavy” or “light” weights? After all, these are completely relative terms, representing different numbers for everybody.

So, here are some guidelines. For our purposes, we'll say that a “heavy” weight is one that limits you to about 8 reps. Typically, this works out to about 70 percent of your 1RM. Granted, you could go heavier. But this rep range is that one that is best suited toward building defined muscle. Which is what you're looking for when trying to shred extra fat.

If your reps approach – and pass – the 15 count, you've now entered the realm of “light” weights. This workout style isn't useless, it's just not what you need when your goal is fat loss. But more on that later.

Immediate Benefits

Actually, we lied. Let's talked about why light weights don't work in this situation right now.

Once your reps get into the 15-or-more range, your muscles are no long working as hard as they  had been in the lower ranges. And that's really the major difference. Essentially, these workouts turn into endurance training. Which most definitely has it's place.

And, generally, these high-rep workouts will actually burn more calories than the low-rep alternatives in the same way that cardio will typically burn more workouts than lifting.

If you're looking to get rid of body fat, though, you need to do more than just burn calories. You need to develop muscle fibers. Otherwise, as you lose weight, you will simply become skinny rather than the cut, defined, toned look that you're actually working for.

Plus, the more muscle fibers that you activate during your workout, the more calories you will burn. And, in order to activate those muscles, you have to challenge them with heavy, exhausting weights.

Long-term Benefits

The real reason why heavy lifting is a better fat-burning tool, though, takes place over the long period of time and – as such – often gets ignored. Put simply, muscle burns more calories than fat, even when you're sleeping. As you build more muscle, then, your metabolism will steadily increase.

Heavy workouts in particular, though, bring with them the added perk of Excess Post-exercise Oxygen Consumption, loving known as EPOC. This effect means that, for up to 48 hours after your workouts ends, your body will continue to burn more calories than it would otherwise.

So, while light-weight workouts have their place, the ability to build more muscle fiber and burn more calories in less time makes heavy lifting a much better tool for shredding fat.

-Jonathan Thompson
Jonathan Thompson is a Certified Personal Trainer and Nutritionist with over a decade of experience writing about all things health and fitness. In addition to plenty of articles and blog posts, Thompson is also the author of the book Weighted Vest Workouts.