In 2007, Jim Karas wrote the book,” The Cardio-Free Diet." The book was highly controversial and was condemned by cardiologists and other health professionals. The author claimed, "Cardiovascular exercise kills a weight-loss plan, your internal organs, your immune system, your time and your motivation. If your true goal is to lose weight, interval strength training is the only way to go." The author wrote the book after his personal experiment with weight loss, he found that he would work up an enormous appetite after running several miles. Karas claimed that his cardiovascular health improved but he still wasn't losing weight. He grew more interested in strength training and started exercising with weights. Gradually, experimenting on himself, he started doing more strength exercise and less cardio -- and his weight went down. Karas was criticized by fitness experts for confusing the public with the facts, although long distance running such as a marathon runners and long distance cyclists and so forth have higher rates of respiratory infections and suppressed immune function. This is well known, contrary to long distance exercise, moderate intensity aerobic exercise increases the immune system. Moderate intensity aerobic exercise increases lymphocytes, results in an increase in immune system T-cells, and an increase in natural killer cells, which are all implicated in a reduced risk of cancer.

Does Cardio Kill Fat Loss?
Contrary to Karas book on aerobic not been helpful for fat loss, peer reviewed research studies have shown aerobic exercise to reduce bodyfat. For example, in 2007, a study was published in prestigious journal of Obesity titled: A dose-response relation between aerobic exercise and visceral fat reduction: systematic review of clinical trials. The review article documented that in a when 582 subjects from various studies were analyzed, visceral fat decreased significantly with aerobic exercises that were performed at brisk walking, light jogging or stationary ergometer, and that there is a dose-response relationship between aerobic exercise and visceral fat reduction in obese subjects without metabolic-related disorders1. One thing the study documented was that there was a relationship between the amount of time and intensity spent doing cardio and fat loss. Women may be at a disadvantage compared to men for losing weight thru aerobic exercise. In a previous study, obese men and women trained 5 days a week for 45 minutes a day at 75% of their max heart rate. The obese men had a significant enhancement of metabolism after exercise but not women15. This suggests that aerobic exercise may not be the best choice of exercise to increase metabolism. I read recently the chronicles of a fitness and figure competitor that wanted to complete an IRONMAN triathlon. She trained for seven months, she calculated that she worked out for a total of 374 hours for the Ironman— that's an average of over thirteen hours a week! Amazingly, over the course of seven months, training an average of thirteen to fourteen hours a week, she lost a total of five pounds! She was glad to have said that she completed an Ironman competition but she learned a valuable lesson, steady state cardio is not conducive for fat loss. She said, “For fat loss women should “Learn to Love Intensity, Not Duration! “

Metabolic Rate
Before jumping into what exercise mode is the best for increasing metabolism, lets examine the three components that will determine a woman’s metabolism.

• Resting metabolic rate (RMR) is defined as the energy expenditure necessary to maintain the physiological processes in the post-absorptive state and, depending on the level of physical activity, may represent approximately 60 to 70% of total energy expenditure.

• Diet Induced Thermogenesis (DIT) refers to the increase in metabolic rate above resting levels due to food intake (i.e. high protein foods) and corresponds to approximately 10% of total energy expenditure.

• Physical activity is the most variable component and is related to the energy expenditure necessary for skeletal muscle activity. In sedentary individuals it represents approximately 15% of total energy expenditure, whereas in physically active individuals this can reach 30%

Aerobic Versus Weight Lifting Effects on Metabolism
For a long time, a reduced calorie diet and aerobics exercise has been advocated for weight loss. The problem with aerobic exercise and diet is that studies indicate that, when food restriction is very severe, the combination of aerobic and diet results in losses in lean muscle mass10, 11, consequently leading to a reduction in metabolic rate12. Lean muscle mass contributes to the largest contribution of total metabolism. Be forewarned, if you are a cardio queen…you are not going to like this section! If you have 30 minutes to exercise, you look at the treadmill and then look at the circuit weight training section, which is more effective for fat loss? Researchers compared duration and magnitude of metabolism after exercise in a typical resistance exercise session with that of aerobic exercises with same duration (27 min) and intensity. Results showed that oxygen consumption (a measure of metabolism) remained significantly elevated up to 90 min after terminating the resistance exercises and only 30 min after the aerobic activity. Calories burned after exercise was higher during the first 30 min after resistance exercises than after the aerobic exercise, representing an additional energy expenditure of 95kcals for circuit training and 64 kcal for aerobics13. Sorry, cardioaddicts...Don’t shoot the messenger!


Cardio and Weight Training Better for Fat Loss than Cardio Alone.
It has been shown that if you compare a head to head match for weight loss, performing resistance exercise with cardio is more effective than cardio alone. There are two studies that have shown that if you want to drop body fat: a combination of cardio and weight training is best!

Study 1: In the study, 35 overweight subjects were placed in one of three groups for 12 weeks; diet-only (1500 calories per day); the same diet plus aerobic exercise; or diet plus aerobic and resistance exercise. The exercise programs were supervised by a team of personal trainers. Subjects in the diet and aerobic exercise group trained three days per week using a variety of activities (treadmill walking/jogging, cycling, rowing and stair climbing). The diet plus aerobic and resistance group trained with weights after the aerobic workout. The routine consisted of a complete body workout (machine squat, military press, bench press, lat pulldown, seated row, sit-up, lower back, leg press, hamstring curl, calf raise, and arm curl). The program involved heavy days (5-7 repetitions) and moderate days (8-10 repetitions). They took short rest periods (1 minute) between sets and exercises when using moderate loads and longer rest periods (2-3 minutes) with the heavier loads. Throughout the 12 weeks, subjects were encouraged to increase the amount of weight they used in each exercise. Twelve weeks later, all the groups had lost a similar amount of weight (between 20 and 22 pounds). However, fat loss was greatest and muscle loss was minimized in the group who trained with weights. In the group that followed the low-calorie diet for 12 weeks, 7 of every 10 pounds lost came from fat. In the group combining aerobic exercise with the low-calorie diet, 8 of every 10 pounds lost came from fat. In the group who dieted, exercised aerobically, and trained with weights, almost all of the weight lost came from fat.

Study 2: Thirty obese women were enrolled in the study for six months; the women were separated into three groups: a control group, an aerobic exercise group and a combined exercise group. The aerobic group did one hour of cardiovascular exercise (60-70% maximum heart rate) six days a week. The combined exercise program involved weight training (3 days a week, Monday, Wednesday, and Friday) and aerobic exercise (3 days a week, Tuesday, Thursday, Saturday). At the end of the six months, the loss of fat was greatest in the combined group (19.7 pounds) compared with the aerobics-only (16.3 pounds) group. The combined group also lost almost three times more abdominal subcutaneous fat and 13% more visceral fat than the aerobic-only group. So what is it about resistance exercise that seems to supercharge the metabolism for fat loss? Many people think it’s because resistance exercise increases lean muscle mass which contributes to increased calorie burning. This is true, but researchers suspect that the main benefit of resistance exercise (other than the calories burned during the workout itself) is the effect it has on oxygen consumption after the workout. This is known as excess post-exercise oxygen consumption (EPOC).