Monday, October 4, 2010

Training in the fasted state improves glucose tolerance during fat-rich diet.

I was originally going to write about breakfast and fat loss today, but then I got an interesting email from a lady who is following my articles. Specifically she wanted to know if fasted cardio / endurance exercise is beneficial to losing fat. Her trainer is against fasted cardio because, so he claims, she will lose muscle and get weaker. To top it off, this trainer also has her consume fruit juices and sports energy drink during the workout. Talk about making a bad situation worse. This lady was clearly frustrated with her results and is desperate to find someone that can help her. I’m sure our conversation today will put her on the right path to success.

One of the great debates coaches have amongst each other is whether fasted exercise is a valuable tool, or detrimental, to fat loss and gaining muscle. I believe that fasted exercise, especially when doing cardiovascular / endurance exercise is one of our most valuable tools for causing positive partitioning effects in our body, and in the future you can count on me to review these studies on my blog so I can make you a believer too.

A study I want to review today is quite interesting. Most studies that deal with exercise and obesity usually have the subjects consume 70% carbohydrates, 15% protein, and 15% fat. Although this type of diet is far from ideal for losing fat and gaining muscle, most studies do show that fasted exercise does result in a large amount of fat oxidation versus doing exercise in the fed state.

The researchers investigated whether exercise training in the fasted state is more potent than exercise in the fed state to induce favorable adaptations in whole-body glucose tolerance and insulin sensitivity during a period of hyper-caloric fat rich diet. .All volunteers were male, healthy, between the ages of 18 and 25. The length of the study was 6 weeks. Exercise was performed four days a week, two-60 minute sessions and two-90 minute sessions of running (85% of Vo2Max) and cycling (70-75% of Vo2Max). Three groups; the fasted group (exercise performed in a fasted state) but consuming a hyper-caloric fat-rich diet (50% of calories came from fat, and consuming 30% more calories than required to maintain a stable weight).Group two, the carbohydrate group, which ate breakfast 90 minutes before exercise consisting of 675 calories with a macronutrient ratio of 70% carbohydrates, 15% fat, 15% protein (118 grams of carbs!!!) plus consuming a beverage containing 1gram of maltodextrin per kilogram of bodyweight during exercise, and finally group three, no training, but same diet as group one and two.

The results: the fasted group gained 0.7 kilograms (kg) in bodyweight, the carbohydrate group gained1.4 kgs of bodyweight, and group three gained 3 kilograms of bodyweight. Glucose tolerance and insulin sensitivity increased more in the fasted group than the carbohydrate group. Muscle GLUT-4 protein content was increased by 285 in the fasted group and only by 3% in the carbohydrate group. I will stop here about the results and get to the point, “This study for the first time shows that fasted training is more potent than fed training to facilitate adaptations in muscle and to improve whole-body glucose tolerance and insulin sensitivity during hyper-caloric fat-rich diet.” If your glucose intolerant and insulin resistant, fasted exercise will be of great benefit to you.
The fasted group consumed approximately 1000 more calories than the carbohydrate group and only gained 0.7 kgs (insignificant).why did the carbohydrate group gained double the weight while following the same exercise program? Nutrient partitioning! If you can set up your diet and training program properly to include more fat, more protein, less carbohydrates, and fasted exercise, you will see some very pleasant results in your body composition. If your working with a trainer, doctor, nutritionist, or whatever, that recommends consuming carbohydrates during exercise, I suggest you fire them immediately.

Just so we are clear, fasted means fasted. No food at all. Some coaches recommend a small amount of fat and/or proteins before or during early morning exercise and still calling it “fasted” exercise. That’s not fasted. Fasted to me means at least 7 hours since your last meal and preferably when you wake up. One last warning; please don’t duplicate this study. It was an experiment, the results were positive, and let’s leave it there. Consuming an extra 1000 calories on a fat-rich diet while doing fasted cardio resulted in an insignificant amount of weight gain. Imagine what would happen if the diet was set up correctly. Later this week I will explain what happens when you do consume carbohydrates during a workout.