Why Cardio Doesn’t Help You Lose Weight

Why Cardio Doesn’t Help You Lose Weight


Losing weight… You hate thinking about it but it’s always on your mind.


Cardio is the most common way I see people attempt to lose weight on their own – whether it’s on the treadmill, a rowing machine, or a bike on the road.


Instead of attempting to lose weight through cardio, your approach should be losing weight through metcons (short for “metabolic conditioning”). Metcons are superior to cardio sessions due to the nature and interaction of the body’s metabolic pathways.


In today’s article, I’ll first define what metabolic conditioning is. Then, I’ll explain the difference between anaerobic and aerobic exercises – and why cardio movements should be performed in anaerobic intervals. Finally, I’ll conclude with a better approach to losing weight.


Metabolic Pathways


“Cardio” is typically any of the following movements: biking, running, swimming, rowing, speed skating and cross-country skiing. The vast majority of cardio is ineffective because it either isn’t performed long enough to gain any benefit, or the pacing is that of my grandma.


There are three metabolic pathways that provide the energy for all human action. These “metabolic engines” are known as the phosphagen (or phosphocreatine) pathway, the glycolytic (or lactate) pathway and the oxidative (or aerobic) pathway.




The first, the phosphagen, dominates the highest-powered activities, those that last less than about 10 seconds. The second pathway, the glycolytic, dominates moderate-powered activities, those that last up to several minutes. The third pathway, the oxidative, dominates low-powered activities, those that last in excess of several minutes.


Total fitness requires competency and training in each of these three pathways or engines. Balancing the effects of these three pathways largely determines the how and why of the metabolic conditioning that we do at RxFIT.


Favoring one or two to the exclusion of the others and not recognizing the impact of excessive training in the oxidative pathway are arguably the two most common faults in fitness training.


Anaerobic vs Aerobic


Of the three metabolic pathways the first two, the phosphagen and the glycolytic, are “anaerobic,” and the third, the oxidative, is “aerobic.”


Aerobic conditioning allows us to engage in low-power extended efforts efficiently. Whether it’s a long bike ride or run, these efforts will improve cardiovascular function and endurance. They can decrease body fat when performed for hours. But I have good news for you: there’s a more effective way to get fit.


Anaerobic activity also benefits cardiovascular function and is superior to aerobic exercise for fat loss! Anaerobic activity is unique in its capacity to dramatically improve power, speed, strength and muscle mass. High intensity exercises allows us to exert tremendous forces over brief time intervals. You can use anaerobic efforts to develop aerobic conditioning by training in intervals.


Interval Training


The key to developing the cardiovascular system without a significant loss of strength, speed and power is interval training. Interval training mixes bouts of work and rest in timed intervals.


The table below gives guidelines for interval training. We can control the dominant metabolic pathway conditioned by varying the duration of the work and rest interval and number of repetitions.




Interval training doesn’t need to be so structured or formal. One example would be to sprint between one set of houses and then jog between the next set. You can alternate in this manner for the duration of a 20-minute run in your neighborhood.


Why Cardio Doesn’t Lose Weight


In summary, cardio doesn’t lose weight because of your approach.


The days of watching a t.v. show on the stair stepper or listening to a podcast while riding your bike are long-gone. There is certainly a time and place for long bouts of cardio sessions, but they should be treated more as “recovery days” instead of training days.


In order to elicit fat-burning long after your workout, the bulk of your training should be metcons.


We are in search of elite fitness – the kind that produces collegiate and professional athletes. Just look at what these high school athletes look like at the end of their senior year, and then look again at their bodies after their freshman year in college sports. Elite training breeds elite health. And elite training is performed in metcons.


Take any collegiate sport and look into their training regimen. No one is training with ear buds and low heart-rates.


The basketball players are sprinting “suicide” intervals under one minute or performing anaerobic plyometric exercises.


The wrestlers are dripping in sweat while performing large sets of pull-ups, push-ups, and sit-ups.


The cross-country athletes are running alongside each other while timing their miles with a wrist watch.


In short, no one is leisurely exercising. Your litmus test should be that of breathing heavy and sweating a lot. “Training” implies working hard – not being entertained by some episode on your phone.


If your goal is to lose weight, stop doing cardio and start metcon training.




*This article was originally inspired by Greg Glassman. You can find it here.

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