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Fasting Slows You Down

Fasting for just a few hours slows an athlete down and the longer he fasts, the slower he moves. A recent study from Denmark shows that after 72 hours of fasting, a person's muscles accumulate far more fat and glycogen (stored sugar) than after 10 hours of fasting (American Journal of Physiology, Endocrinology and Metabolism, January 2012). This slows a competitive athlete down because it keeps muscles from responding to insulin and using more sugar for energy.

Insulin drives sugar into muscles most effectively when muscles are low on sugar and fat. Filling muscles with sugar or fat blocks insulin and reduces the amount of sugar that can enter muscle cells. Remember that when you exercise for more than an hour, you need to keep on taking sugar. The more intensely you exercise, the greater percentage of sugar your muscles use for energy. Emptying your muscles of sugar causes sugar to enter muscles even faster.

LACK OF SUGAR LIMITS SPEED: The time it takes to get oxygen into muscles is the limiting factor for how fast an athlete can move in competition. If he can get more oxygen into muscles, he will move faster. Muscles use fat, sugar and (to a lesser degree) protein for energy. Since sugar requires the least oxygen, an athlete moves faster when his muscles burn a greater percentage of sugar. If he fasts, he gets almost all of the energy to drive his muscles from his own body fat. Using fat for energy requires more oxygen, so he has to slow down.

MUSCLES CAN STILL FILL WITH SUGAR DURING FASTING: How can muscles start to fill up with sugar after three days of fasting? With fasting, the body breaks down its own protein for energy. Protein is made up of chains of building blocks called amino acids. Some of the amino acids are called branched-chain amino acids. The liver can convert these amino acids into sugars (called gluconeogenesis) which then travel in the bloodstream to be stored in muscles as glycogen.

HOW TO EAT TO COMPETE: If you are competing in sporting events that require speed, you should eat a meal that contains carbohydrates closer than three hours before the start of your event. If the event lasts more than an hour, take some source of sugar during your event, such as sugared drinks, fruit, candy, grain bars or dried fruit paste (fruit leather).


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Diabetes Should Never Happen to You

One of three North Americans will become diabetic, and almost all are pre-diabetic long before they become diabetic. Signs of pre-diabetes include:

• a protruding belly
• small buttocks
• love handles around the belt line
• high triglycerides (greater than 150)
• low HDL (good) cholesterol (lower than 40)
• fatty liver
• fasting blood sugar above 100
• blood sugar above 120, two hours after eating

If you change the habits that cause the signs of pre-diabetes, you can probably avoid ever becoming diabetic.

EXERCISE HELPS TO LOWER HIGH BLOOD SUGAR LEVELS. People who are pre-diabetic have a far more dramatic lowering of high blood sugar and insulin with exercise than non-diabetics (Medicine and Science in Sports and Exercise, December 2011;43(12):2231- 2240). High blood sugar levels cause sugar to stick to the outer surface of cell membranes and destroy them. High blood insulin levels constrict arteries leading to the heart to cause heart attacks.

INTENSE EXERCISE IS FAR MORE EFFECTIVE IN CONTROLLING BLOOD SUGAR LEVELS THAN JUST EXERCISING. In another study, men performed the following workout three times a week: They warmed up by pedaling on a stationary bicycle for five minutes, performed two 20-second hard sprints and then cooled down by pedaling slowly for five minutes (European Journal of Applied Physiology, December 2011). After six weeks, there was an incredible drop in blood sugar and insulin levels, far more than a diabetic achieves by exercising less intensely for more than one hour a day. The authors write: "These sprints break down as much glycogen in two 20-second sprints as moderate endurance exercise would in an hour."

Muscles store sugar inside their cells as glycogen. Emptying muscle cells of glycogen markedly improves the ability of muscle cells to remove sugar from the bloodstream.

BAD HABITS THAT CAUSE DIABETES: If you have type II diabetes, you probably did it to yourself. More than 90 percent of diabetes is caused by inability to respond to insulin. Insulin cannot do its job of driving sugar from the bloodstream into cells until it attaches on special hooks on cell membrane called insulin receptors. So anything that blocks insulin receptors prevents insulin from working and causes blood sugar levels to rise too high. Also, anything that drives sugar into cells without needing insulin helps to prevent and treat diabetes. Behaviors that block insulin receptors include:

• EATING RED MEAT. The saturated fat in red meat blocks insulin receptors to prevent insulin from doing its job.

• BEING FAT. Full fat cells block insulin receptors.

• LACKING MUSCLE. Contracting muscles can remove sugar from the bloodstream without needing insulin. However this effect lasts only during exercise and up to 17 hours afterwards, so you have to exercise every day. Exercise draws sugar into cells without even needing insulin, and exercise makes your body respond better to insulin (Medicine & Science in Sports & Exercise, December 2011;43(12):2231-2240).

• LACKING VITAMIN D. Vitamin D is necessary for your cells to respond to insulin. Lack of vitamin D blocks insulin receptors and prevents insulin from doing its job of lowering blood sugar levels. Vitamin D levels should be above 75 nmol/L.

SUGAR AND OTHER REFINED CARBOHYDRATES: Eating or drinking sugar and refined carbohydrates (such as bakery products and pastas) raises blood sugar levels the most. A high rise in blood sugar causes sugar to stick to cells. Once there, sugar can never be removed. It eventually is converted to sorbitol that destroys the cell to cause all the horrible side effects of diabetes: blindness, deafness, heart attacks, strokes, dementia, impotence, kidney failure, amputations and so forth.


Slightly Elevated Bilirubin Prevents Heart Attacks

Men who have high blood levels of bilirubin live longer and have far fewer heart attacks and strokes than men with normal levels (The American Journal of Cardiology, November 2011;108(10):1438-42). Men who have lower than normal levels of bilirubin are at higher risk for heart attacks and premature death (Atherosclerosis, 2001;154:747-754). Men with low bilirubin levels also usually have low levels of the good HDL cholesterol that prevents heart attacks.

MECHANISM: Red blood cells last about 120 days, then burst and release a yellow pigment, called bilirubin, into the bloodstream. The liver picks it up, converts it to bile and flushes it from your body. Some people's livers cannot convert bilirubin into a form that is easily removed, so bilirubin rises to higher-than-normal levels.

Since high blood levels of bilirubin are associated with liver disease and certain types of anemia, doctors often order extra tests whenever a person has high blood levels of bilirubin. Five percent of North Americans have high blood levels of bilirubin and suffer no ill effects from it. These people are usually told that they have Gilbert's disease and have nothing wrong with them. Now we learn that not only is Gilbert's disease not harmful, it prolongs life by helping to prevent heart attacks and strokes. The bad LDL cholesterol in your bloodstream must be converted to oxidized LDL before it can form plaques in arteries. Bilirubin is a powerful antioxidant that helps to prevent oxidized LDL cholesterol from forming, and therefore it helps to prevent heart attacks (Hopkins PN et al. Arteriosclerosis, Thrombosis and Vascular Biology, February 1996).

WHAT TO DO IF YOUR BILIRUBIN IS ABOVE 1.9 mg/dL: Normal bilirubin is is between 0.3 & 1.9 mg/dL. High bilirubin can be caused by excessive bursting of your red blood cells; liver damage or infection; or gallbladder, pancreatic or bile duct disease. Your doctor will order liver function tests. If they are normal, the odds are overwhelming that you have Gilbert's disease, which is healthful and requires no treatment. Your doctor will decide if he needs to do other tests to rule out more serious causes of an elevated bilirubin.


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January 29th, 2012
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About the Author: Gabe Mirkin, MD

Sports medicine doctor, fitness guru and long-time radio host Gabe Mirkin, M.D., brings you news and tips for your healthful lifestyle. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology. The Dr. Mirkin Show, his call-in show on fitness and health, was syndicated in more than 120 cities. Read More
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