|
|
|
|
carbohydrates
Carbohydrates are the primary energy source in human nutrition. They fuel our bodies and should therefore make up 55-60% of our daily calorie intake. Carbohydrates provide us with energy in a very economical way, because most of them can easily be digested. Additionally they are the basic product of the synthesis of fats and proteins.
structure
Carbohydrates are made of sugars, so called saccharides, consisting of the elements carbon, hydrogen and oxygen. Simple sugars are the basic elements of all carbohydrates.
classification
There are four types of saccharides: monosaccharides, disaccharides, oligosaccharides and polysaccharides. Each with different attributes and nutritional relevance.
name |
examples |
attributes |
sources |
monosaccharides
(simple sugars) |
glucose (dextrose),
fructose,
galactose,
ribose |
water-soluble,
crystalline structure,
sweet taste,
colorless,
fast absorption |
components of polysaccharides,
fruits, honey |
disaccharides |
sucrose (table sugar),
lactose (milk sugar),
maltose,
trehalose,
cellobiose |
water-soluble,
crystalline structure,
slightly sweet to sweet taste,
colorless,
fast absorption |
sucrose is part of sugar beets,
milk contains lactose,
maltose occurs in germinating barley |
polyaccharides |
glycogen,
starch
|
water-insoluble,
need to be broken up by enzymes before digestion,
no sweet taste,
slow absorption |
the body uses glycogen as energy storage in muscles and liver,
starch is found in potatoes, grain, vegetables |
polysaccharides
(roughage) |
cellulose,
pectin |
water-insoluble,
indigestible,
they bind toxics,
stimulate digestion
|
food from plant like fruits, vegetables, grain, legominous plants |
energy recovery
The human organism can only handle simple sugars, that´s why all polysaccharides need to be digested and broken up into its basic component, glucose. Inside the cells glucose is converted into chemical energy (ATP = Adenosinetriphosphate) and warmth. This process is called glycolysis.
One gram of carbohydrates delivers 17 kJ (that´s 4,2 kcal) of energy.
glycemic index (GI)
The glycemic index is a ranking system, describing the time any food releases its sugars into the blood and therefore effects the blood glucose level within the first two hours. The lower the glycemic index, the more time this process takes and the higher the foods quality.
high GI |
medium GI |
low GI |
white bread, white rice, corn flakes, ice cream |
table sugar, any muesli, dried fruits |
basmati rice, fruits and vegetables, oats, wholemeal |
After eating carbohydrates the blood glucose level rises slightly within the first hour. Now the pancreas distributes the hormone Insuline to normalize this level. Cells absorb glucose and produce energy. As your metabolism doesn´t need any energy, the Insuline stimulates the fat cells to absorb glycogen and to transform it into fatty acids.
consumption reference
general consumption notes:
Carbohydrates should preferably consumed in the most natural form. Avoid processed food like white floor, peeled rice or refined sugar. These products are full of empty calories (lots of energy, little vital substances). Don´t consume too much carbohydrates. The body will store the unused energy as fat.
mono- and disaccharides:
Best time to have short term energy delivering mono- or disaccharides is after training to refill your muscles glycogen storages. The time window here is about 10 minutes. Afterwords it becomes harder for your body to include these sugars into its metabolism. Besides they are a perfect "brainfood" when your´re lacking in concentration, because the brain can only process glucose.
Fructose from fruits can be eaten anytime, because its glycemic index is the lowest among monosaccharides. As you´re about to loose some weight don´t consume fruits in the evening, because the blood glucose level has to be as low as possible when going to bed.
polysaccharides:
Food containing mainly polysaaccharides can be eaten in large amounts. Have at least 130-150g of complex carbohydrates per day, because the bodys storage capacities in muscles and liver is limited and brain and nerves permanently need glycogen.
Best sources are wholemeal products, potatoes and brown rice.
|
|
|
|
|
|
