February 3, 2021

Falsehoods of Fitness: Cardio Is a Great Way to Lose Fat

Are you tired of working endlessly to get rid of that last little bit of stubborn fat around the midsection?

A row of treadmills in a gym
Cardio for Fat Loss

Most people are intimidated by free weights and resistance training, so they head for the bikes, treadmills, rowers, and ellipticals to lose weight and improve their physique.

Bodybuilders and fitness personalities devote hours to these machines, and we assume that it’s a great avenue for burning fat.

However, what if I told you there might be a better way to burn fat than endless hours on cardio machines or sidewalks?

Believe it or not, you can spend little to no time in the gym and get better results.

Is Steady-State Cardio Really the Best Method to Burn Fat?

There are several reasons why long, low-intensity cardio sessions may actually hinder fat burning. Prolonged cardio sessions upregulate cortisol, a stress hormone, which can hinder your fat loss goals in two ways.

Cortisol inhibits lipolysis, the breakdown of lipid molecules (fat)

One review1 of 31 studies investigating physical activity’s effect on fat loss found only small weight reductions (0.04–0.18 lbs) after 12 weeks of prolonged exercise. Another review2 found that only 2 of 13 studies showed statistically significant weight loss benefits for exercise and diet modification compared to the diet modification alone.

For studies comparing exercise to no intervention, the results were slightly better. However, observed weight loss was still just 2–4 lbs after exercise, and some of these studies involved exercise interventions lasting more than one year.

These tiny numbers (in most of the cases, statistically insignificant differences) can be disheartening for spending hours a week doing prolonged cardio sessions.

Cortisol promotes proteolysis, the breakdown of protein molecules (muscle)

Higher cortisol levels can cause muscle tissue to break down over time. Think about it—have you ever seen a big, muscular marathon runner? (Hint: they don’t exist!)

This might make one wonder if some of the small weight loss “benefits” seen in the studies referenced above were actually muscle loss rather than fat loss.

Now, if you are training for an endurance event, this type of training is necessary to achieve greater muscular endurance and aerobic capacity.

If fat loss is the goal, however, this type of training is not very efficient and may be burning your muscle instead of fat.

Is Prolonged Cardio Safe on Joints?

Man running with injured knee

You may have heard or used the term “pounding the pavement” when referring to going for a long run. While walking is relatively low intensity, running on the road or sidewalk may cause unnecessary wear and tear on your body’s joints—primarily the hips, knees, and ankles.

A systematic review3 of 17 studies found lower-extremity injuries ranged from 19.4% to almost 80%, primarily in the knee. The authors also found that long training distance per week and previous injury were risk factors for running injuries.

Another study4 found increased impact forces and loading rates in older men when compared to younger men, which suggests that we lose our ability to absorb and redirect force as we age.

Cardio versus Resistance Training for Weight Loss

A woman runs to lose fat

Several forms of cardio and resistance training can help with physique goals, although some are more efficient than others.


Some of the most popular forms of prolonged forms include walking, running, cycling, and swimming due to the minimal equipment requirements. You may find pricey equipment at commercial gyms such as treadmills, ellipticals, rowers, and ski ergs. Most people use these machines for a long time, up to two hours, at a low speed or with low resistance.

Resistance Training

Like cardio, there are many forms of resistance training—bodyweight, free weights, machines, and bands are the most common. Free weights include barbells, dumbbells, kettlebells—objects you can move to target certain muscle groups.

Machines typically use a pulley system with cables attached to weight stacks - these require less stabilization than free weights because the movement path is relatively fixed.

Resistance bands are rubber bands of varying thickness, offering varying degrees of difficulty. The use of bands is called variable resistance because the resistance varies as the band is stretched—the further it’s stretched, the more difficult it becomes.

One study found improvements in strength (19%) and decreases in body fat mass (~4 lbs) after 20 weeks of variable resistance training5.

With X3, you train with greater force to trigger Greater Gains

Cardio for Fat Loss: The Verdict

So, although prolonged cardio may have some cardiovascular health benefits, it is not very efficient in burning body fat or retaining muscle mass.

Long cardio sessions can increase cortisol and cause wear and tear on the joints.

Resistance training can increase testosterone and provide a more efficient method to burn fat and retain, or even build, muscle mass.

Specifically, variable resistance training methods provide a superior stimulus for burning fat and retaining (or with sufficient protein intake, substantially building) your hard-earned muscle.

More in-depth information can be found in Dr. John Jaquish’s book, Weight Lifting Is a Waste of Time: So Is Cardio, and There’s a Better Way to Have the Body You Want.

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