Ever watch that show on the Discovery channel called “Myth Busters?” In short, two dudes separate truth from urban legend with the aid of modern-day science. Some past episodes include:
1. Can the unaided human voice shatter glass?
2. Can a penny dropped from a tall building kill someone on ground level?
3. Is it possible to break off a lock by shooting it with a gun?
4. Is it true that no woman can resist my uncanny charm and wit?
It’s a great show, and it’s always interesting to find out what is fact and what is fiction. In the case of #4 on the list above, it’s totally fact. I wrote it on the internet, so it must be true.
Nevertheless, I’d like to take this opportunity and play Myth Buster for some common myths and fallacies that we often come across in the fitness world. First on the hit list: The addition of aerobic training (ie: step class, endless hours on the elliptical machine) to a caloric deficit (through diet) will increase calories burned and therefore increase fat loss. True or false?
This is a myth that my good friend Alwyn Cosgrove tackled in his book “Real World Fat Loss: Destroying the Dogma.” In short the answer is undoubtedly FALSE.
How can this be? Personal trainers and group training instructors have always advocated that aerobic exercise is great for fat loss. We add in aerobic exercise, which increases calories burned, which burns more fat, which brings sexy back. Everyone wins.
Problem is, there is a plethora of research out there which states that aerobic exercise is inferior in regards to fat loss:
“Influence of diet and/or exercise on body composition and cardio respiratory fitness in obese women,” International Journal of Sports Nutrition. 1998 Sep; 8(3): 213-22.
Conclusion: the addition of 45 minutes of aerobic exercise at 78% Maximum Heart Rate (MHR), five days per week for twelve weeks had NO EFFECT over dieting alone.
“Does (aerobic) exercise give an additional effect in weight reduction regimens?” International Journal of Obesity. 1987; 11(4): 367-75.
Conclusion: the addition of of four hours of aerobic exercise per week had no effect on weight loss.
“Effects of strength or aerobic training on body composition, resting metabolic rate, and peak oxygen consumption in obese dieting subjects,” American Journal of Clinical Nutrition. 1997 Sep; 66(3): 557-63.
Conclusion: in an isoenergetic comparison, the strength training group lost significantly more fat than the aerobic training group. Additionally the aerobic training group lost significantly more lean body mass than the strength training group.
Despite all the research (and real world evidence), many fitness professionals still advocate aerobic exercise for fat loss. Isn’t it a bit ironic that a large percentage of “fitness or group exercise instructors” have a high body fat percentage themselves? Walk into any class and see for yourself.
Now before I get the hate mail, let me first say that there are many health benefits to including aerobic exercise into one’s weekly routine. But it we’re referring to strictly fat loss, it’s just not going to cut it. End of story.
That being said you need to look at an entire 24 hour day when talking about fat loss. Sure you will burn more calories performing an hour of aerobic exercise compared to an hour of lifting weights. However in a 24 hour period, it’s been shown time and time again that the body will literally burn HUNDREDS more calories through lifting weights due to what is called EPOC (Excess Post-exercise Oxygen Consumption). Long story short, once you’re done doing aerobic exercise, you’re done burning calories. On the flip side, after a strength training session, the body’s metabolism will be elevated for upwards of 24-48 hours, which burns far more calories (and fat).
As Alwyn Cosgrove states in his book, “Someone talking about the benefits of the fat burning zones or fasted cardio is a sure sign that the individual has stopped looking at the end of the exercise session. They have come to the conclusion that lower intensity, steady state exercise (aerobic) burns the most fat and made a massive leap of faith to suggest it is best for real world fat loss.”
Myth Busted: Aerobic exercise does not increase fat loss.