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Chocolate Increases Endurance

A recent symposium at the American College of Sports Medicine 58th Annual Meeting June 2, 2011 and other recent studies show that chocolate improves endurance training in mice and humans. Taking small amounts of a chocolate extract, called epicatechin, twice a day for two weeks shortened recovery from intense exercise and increased endurance in mice (Journal of Physiology, July 25, 2011). Drinking chocolate milk after all- out exercising helped athletes recover faster and cycle faster afterwards (Journal of Strength Conditioning Research, May 2011).

These studies do not encourage you to take chocolate just before competitions. They show that chocolate helps you to recover faster from hard exercise, and that you may benefit from taking small amounts of chocolate daily during hard training. All athletic training is done by taking a harder workout on one day, feeling sore on the next and taking easier workouts for as many days as it takes for the soreness to go away. If you can recover faster, you can do more intense training and be a better athlete.

Your body requires oxygen to convert food to energy to power your muscles during exercise. The limiting factor to how fast you can run or cycle, and how much force your muscles can generate, is the time it takes to move oxygen from your lungs into your muscles. The aim of all athletic training is to increase your body's ability to convert food to energy with the least amount of oxygen. Anything that increases oxygen supply or decreases oxygen needs will make you faster and stronger.

Your muscles convert food to energy primarily in your mitochondria, small chambers numbering from a few to thousands inside your muscles. Anything that grows new mitochondria or enlarges existing ones will make you faster and stronger. The cocoa bean contains chemicals called epicatechins that stimulate your muscles to grow and produce mitochondria. It takes only small amounts, taken regularly, to do this.

However, pure chocolate is very bitter, so manufacturers add huge amounts of sugar and saturated fats that should not be taken when you are not exercising. Eating refined sugar when you are not exercising causes a high rise in blood sugar that can damage every cell in your body and saturated fats from animals block insulin receptors to prevent insulin from clearing sugar from your bloodstream to raise blood sugar levels even higher.

• You can eat small amounts of sweetened chocolate when you are exercising.
• You should not eat sweetened chocolate when you are not exercising.
• You can eat chocolate every day that you exercise, particularly on your intense exercise days.
• You should take only small amounts as more is not more effective in hastening recovery. A reasonable daily amount would be about five grams of dark chocolate (1/6th of an ounce) per day.


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Dear Dr. Mirkin: How could eating meat cause diabetes?

There are several theories. The most widely-accepted theory is that saturated fat in animal products blocks insulin receptors (American Journal of Physiology, May, 2011). Since insulin cannot attach on its receptor on cells, it cannot do its job of driving sugar from the bloodstream inside cells. Then, blood sugar levels rise causing sugar to stick on and damage every cell in your body.


Dear Dr. Mirkin: Why does sugar increase risk for heart attacks and diabetes?

Most sugars that you eat contain two sugars called glucose and fructose. Fruit sugar and table sugar from cane or beets contain sucrose: glucose and fructose bound together in a single molecule. High fructose corn syrup (HFCS) in most soft drinks contains glucose and fructose separately. Only single sugars can be absorbed from your intestines into your bloodstream.

ONLY GLUCOSE CIRCULATES IN YOUR BLOODSTREAM. Of all sugars, only four (glucose, fructose, galactose and mannose) can pass from your intestines into your bloodstream. Only glucose is allowed to circulate in your bloodstream. The other three are converted to glucose in the intestines or pass to the liver and do not reach the general circulation.

WHY FRUCTOSE IS HARMFUL: In just two weeks, high doses of fructose markedly increase blood levels of the bad LDL cholesterol, triglycerides and apolipoprotein-B (a protein that causes plaques to form in arteries). These are blood markers of increased risk for diabetes and heart attacks. Those taking comparable amounts of glucose do not suffer these changes (Journal of Clinical Endocrinology & Metabolism, October, 2011).

FRUCTOSE IS CONVERTED TO TRIGLYCERIDES OR LIVER GLYCOGEN. Fructose is not allowed to circulate in the bloodstream. It is first converted in the liver to a stored sugar called glycogen and when your liver fills with glycogen, it is then converted to triglycerides to cause high blood levels that increase heart attack risk.

TRIGLYCERIDES CAUSE HEART ATTACKS. There is only a limited amount of glycogen that can be stored in the liver, so when you take in high levels of fructose, almost all is converted to triglycerides. Then your liver takes 1500 triglyceride molecules and a lesser number of cholesterol molecules to form the bad LDL cholesterol that causes plaques to form in arteries. So fructose is a major player in the formation of plaques that can eventually break off from arteries to cause heart attacks.

FRUCTOSE IS SAFE DURING HARD EXERCISE. When you are exercising, fructose is not harmful. The first fructose is stored in your liver as glycogen which can be released as glucose into your bloodstream. Your brain depends on glucose for more than 98 percent of its energy. Your muscles depend on glucose as an energy source also. There is only enough sugar in your bloodstream to last about three minutes, so your liver has to constantly release sugar from its glycogen stores into your bloodstream.

When you start to exercise, your muscles draw sugar rapidly from your bloodstream. To maintain blood sugar levels, your liver markedly increase its release of sugar from its glycogen stores. So most of the fructose you take in during exercise is converted to liver glycogen and then glucose to be used by your exercising muscles for energy. ALL FRUCTOSE-CONTAINING DRINKS, INCLUDING FRUIT JUICE, CAN BE HARMFUL. When you are not exercising, all sugared drinks are equally damaging to your arteries. Fruit and cane sugars contain glucose and fructose in 50/50 proportions. HFCS contains about 55 percent fructose and a lesser amount of glucose. Fructose from any source is harmful only when it is converted into large amounts of triglycerides.

• Avoid all sugared drinks, including fruit juices and those sweetened with HFCS, when you are not exercising. All are sources of fructose and are equally damaging to your health.
• Restrict foods with added sugars when you are not exercising.
• Eat large amounts of vegetables and fruits.


Recipe of the Week:

Cioppino (Italian Seafood Stew)

You'll find lots of recipes and helpful tips in The Good Food Book - it's FREE


August 7th, 2011
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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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