The Cardio-Free Diet
You may have heard about the controversial new book, The Cardio-Free Diet, by Jim Karas, just published on April 10, 2007. In it, Karas claims that cardio fails to help you lose weight, that it makes you hungrier and less fit, that it damages your joints and your energy level. He recommends a weight-lifting, strength-training regimen that includes no aerobic activities. He claims that with The Cardio-Free Diet you can achieve significant fat loss and lean muscle gain by working out just 20 minutes three times a week.
Karas’s brash statement that “cardio kills” has created a lot of controversy and made his book a best-seller. But is it accurate?
Let’s examine Karas’s claims in The Cardio-Free Diet in the light of expert medical opinion. When ABC News covered The Cardio-Free Diet, they featured several fitness experts who vehemently disagree with Karas. Exercise physiologist Richard Weil, director of the weight-loss program at the New York Obesity Research Center at St. Luke’s-Roosevelt Hospital Center, says that Karas’s claims are simply untrue. There is some evidence that ultra-endurance athletes, such as marathon runners, who typically exercise several hours daily, may suffer from weakened immune systems and joint injuries. But for the recreational exerciser who does 30 to 60 minutes a day of walking, jogging, aerobics class, stair-climbing, or elliptical trainer, it’s just the opposite. Studies show that those folks enjoy stronger immune systems and, in most cases, stronger joints and less joint pain compared to those who do not exercise.
Another expert underlines the same point, saying that the “dangers” of cardiovascular training Karas brings up are very real, but only if someone is operating on the extreme end of endurance or ultra-endurance exercise (which most people never do). He concludes that most people will get the best results by doing both strength training and cardiovascular activities. He also points out that the media love to hype up extremes, and that the balanced approach just doesn’t make for best-sellers and high ratings. Good point!
So why is it that when you go to the gym you see mostly men lifting weights and mostly women doing cardio? For both men and women, there should be a combination of both. Aerobic means “with oxygen.” These exercises are usually performed under moderate intensity levels for generally long durations of time (30 - 60 minutes). Aerobic exercises strengthen your lungs, heart, and the circulatory system. They make your heart stronger by allowing it to transport more blood throughout the body with fewer beats. The more oxygen your muscles get, the longer and harder they can operate.
Anaerobic exercises are called that because your muscles are “without oxygen” (anaerobic) for a short period of time. The intensity is so high that oxygen metabolism can’t keep up. Anaerobic activities include weightlifting and running really fast (sprinting). When you do these, you are performing at such a highly intense level that the available sugars in the blood are immediately converted to lactic acids. That’s why you feel a burning sensation in your muscles until the lactates can be cleared out.
So what do we recommend? Balance! The ideal workout has five components:
- Warm-up
- Aerobic (cardio)
- Anaerobic (strength training)
- Flexibility (stretching)
- Cool-down
Pretty simple and very effective. Not extreme like The Cardio-Free Diet.
We’ll cover each component of the workout in more detail in another article. For now, let’s just say that the best guide to a balanced, effective fitness program that we know is Tom Venuto’s Burn the Fat, Feed the Muscle. It’s based on sound, proven principles. And by the way, it’s been a best-seller for five years running. Highly recommended!