Carbohydrates Facts And Function

March 20, 2015 - Nutrition

Is carbohydrates good or bad?

Fattening or fuel?

How much is too much?

Confusions like this ones keeps people from properly balancing their diets.So we try to eliminate this confusions and you can make choices that best promote your health,weight,and performance.

The forms and sources of carbohydrate are not alike.There are simple and complex carbohydrates.The simple carbohydrates are monosaccharides and disaccharides(single- and double-sugar molecules).Glucose,fructose and galactose are monosaccharides,the simplest sugars.

Common sources of disaccharides are table sugar(sucrose),milk sugar(lactose_a combinacion of glucose and galactose),corn syrup and honey.They contain glucose and fructose but in differing amounts.Table sugar breaks apart into 50% glucose and 50% fructose.The high-fructose corn syrup breaks down to about 55% fructose and 45% glucose.Honey contains about 30% glucose 39% fructose,10% other sugars,17% water,4% miscellaneous particles.Your body converts the monosaccharides and disaccharides to glucose to fuel your muscles and brain.

Fruits and vegetables contain a variety of sugars in differing proportions.Human body absorbs different sugars at different rates.So consuming a variety of sugars allows for better absorption during exercise.Sugar in any form-honey,brown sugar,raw sugar,corn syrup or jelli-has insignificant nutritional value,and your body digests any type of sugar into glucose before using it for fuel.

Complex carbohydrates(starch in plant foods and glycogen in muscles)are formed when sugars link together to form long complex chains.Plants store extra sugar in the form of starch.For example, corn is sweet when is young and becomes starchy as it gets older Its extra sugar converts into starch.In contrast to the vegetables the fruits convert starch into sugar as they ripen.The starches you eat are digested into glucose and then are burned for energy or stored for future use-in the form of muscle glycogen and liver glycogen(but generally not as body fat)This glycogen is available for energy during exercise.The carbohydrate in fruits,vegetables and grains provides energy,vitamins,minerals,fyber and phytochemicals-everything your body needs to function best.(the carbohydrate in sugary soft drinks and polymer sports drinks provides energy but no vitamins or minerals)The continuous intake of excess calories from carbohydrate will eventually contribute to weight gain.When your glycogen stores are filled ,the excess calories will be stored as body fat.Carbohydrate is not fattening.Excess calories are fattening-butter,oil,mayonnaise.Fat provides 36 calories per teaspoon compared with 16 for carbohydrate.

If you are trying to stay away from carbohydrate because you mistakenly believe carbohydrate to be fattening,think again.They are not fattening and you need them to fuel your muscles.The average 150-pound(68 kg)male has about 1800 calories of carbohydrate stored in the liver,muscles and blood in approximately the following distribution:

Muscle glycogen 1400 calories
Liver glycogen 320 calories
Blood dlucose 80 calories
Total 1800 calories

The carbohydrate in the muscles is used during exercise.The one in the liver gets released into the bloodstream to maintain a normal blood glucose level and feed the brain.These limited carbohydrate stores influence how long you can exercise.When the glycogen stores get too low you feel overwhelmingly fatigued and yearn to quit.During low-level exercise such as walking,the muscles burn primarily fat fot energy.During light to moderate aerobic exercise(jogging)stored fat provides 50 to 60 % of the fuel.For hard exercise(sprinting,racing)you rely primarily on glycogen stores.

The well-trained muscles have the ability to store about 20 to 50%more glycogen than can untrained muscles.

Many athletes are skimping on carbohydrate foods because of the fear it is fattening or that high protein intake is better for muscles.Low-carbohydrate diet can hurt performance.3 to 5 grams of carbohydrate per pound of body weight(6 to 10 grams per kg) or 55 65% is the best recommended by most professionals.

In a landmark study researchers compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein,high-fat or high-carbohydrate diet.The subjects on the high-protein,high-fat diet(similar to an Atkins-type dietr) remained glycogen depleted for five days.The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days.This result shows that protein and fat are not stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Depleted muscle glycogen causes athletes to hit the wall,depleted liver glycogen causes them to bonk or crash.Liver glycogen maintain a normal blood sugar level essential for the brain function.When the liver is releasing inadequate sugar into the bloodstream an athlete may feel uncoordinated,unable to concentrate and weakened.The muscles can store glucose and burn fat ,the brain does neither.The poorly fueled brain limits muscular function and mental drive.Carbohydrate unlike protein or fat is needed to fuel muscle-building exercise(protein is also important).Bodybuilders need a carbohydrate-rich diet for building muscles.Research suggests that three sets of biceps curls(8-10 repetitions per set) reduce muscle glycogen by 35%.With repeated days of low carbohydrate and high repetitions,the muscles can soon become depleted.After exhaustive sessions your depleted muscles need at least one day,if not two to refuel.Many athletes hesitate to exrcise less because they are afraid of getting out of shape.Remember that rest will enhance ,not hurt your performance.Athletes whu underestimate the value of rest suffer with injuries chronic glycogen depletion,chronic fatigue.If you are severely overtrained,you may need weeks,if not months to recover.