tapping the body's fat in training

from http://www.bikeradar.com/fitness/article/health-burn-fat-better-1065

Health - Burn fat better (BikeRadar ©)

By Joe Beer

For fitness riders, the question "Why would I want to be able to burn fat?" begs the obvious answer - to get in better shape and look it. But for fit athletes who already have a well-worked lipolysis system, the answer might not be so obvious.

But tapping the body's fat in training increases endurance, reduces the likelihood of 'bonking' and increases fitness. So how exactly do you improve it?

Starting with the basics, you have two choices of fuel; carbohydrate and fat. Carbs provide around 1,500 to 2,000 calories when muscles are fully 'carbo loaded'. This 'higher-octane' fuel can help you go long by combining with fat use or it can fuel quick efforts or sustained high-intensity riding on its own.

The fat stored under your skin and within muscles themselves is a very high calorie fuel depot

Even lean riders like Lance have over 30,000 calories stored as fat, and there are quite a few fit riders carrying well over 100,000. This is clearly a significantly larger potential fuel source than carbs. Fat use generally increases steadily as a ride draws out, starting with the use of fat droplets stored in the muscle and then gradually using fat circulating in the blood stream that is coming off the 'chub' stores spread around the body.Tapping the generous body fat stores saves limited glycogen, but remember even at steady riding levels you will still use carbs.

FAT BURN TIP -- Keep the ride intensity under 80% of your max heart rate (HRmax) and ride for long periods

Build the engine

Training is crucial for optimising your dual fuel burning engine. If you can increase your oxygen carrying capacity and the architecture of fat use by riding regularly you will be many times more efficient than the irregular rider.

Studies show that one effect of training regularly is that less lactate is produced at a given level of effort. For example, unfit people (VO2max=25-35ml.kg.min) may have a significant increase in lactate (LT or Lactate Threshold) at 50%VO2max. Trained athletes (VO2max60-70ml.kg.min) are likely to have this same lactate increase at around 70 to 80%VO2max.

More importantly, data suggest that fat usage may be 80% higher in athletes compared to obese individuals. Data from well-trained riders in the study (VO2max of 64ml.kg.min) suggests that fat use stops above 87%VO2max, and the peak area is around 45 to 65%VO2max. This equates to around 70 to 85%HRmax. If you want to work out the approximate percentage of VO2max you are working at, use this equation... %VO2max = (%HRmax x 1.345) -50 Eg riding at 80%HRmax gives (80 x 1.345) - 50 = 57.6% VO2max.

FAT BURN TIP -- Training regularly, even turbo training sessions, helps use fat as fuel more than any special food, supplement or psychological trick and during a 2-hour endurance ride does not save glycogen but it does significantly decrease the use of fats stored within the muscle fibres

Type One 'endurance' muscle fibres were found to be the main area of fatty droplet use. Interestingly, glycogen storage after fasted sessions, on water alone, was much greater than the feeding during the ride. This suggests these fasted water-only rides up to 2 hours could be used to boost peak levels of fat use by 50% and post-exercise muscle glycogen storage by 200%.

However, for all those pulled in by 'fat burning' spinning sessions, aerobics classes and 'step', be sure you are number savvy. Fat use probably only provides 0.5g to 1g per minute. This will be greater during later stages of training sessions and in very fit riders (maybe 600 to 800 calories per hour). But, a carb meal 30 to 90 minutes before your ride will greatly turn down your fat burning engine, switching to more carbs.

FAT BURN TIP -- Fasted rides (when you don't eat before going out) on water or fasted rides on a 5% fluid replacement drink tap fat

Have breakfast after the ride (if you're going over 2 hours eat breakfast on the bike in the form of regular carb foods - about 40 to 60g per hour)

Take a rider with bad meal timing; lack of consistent riding, who's training too hard and fat use will be very poor. However, if you leave 2 hours between eating and riding, train fasted up to 2 hours once a week, keep in your steady riding zone (60 to 80%HRmax) most of the time and stay consistent, then you will be a good fat burner.