Carbohydrates and fat in the body
Two of the major macronutrients found in food are carbohydrates and fats. Carbohydrates are the ideal nutrients needed to meet the body’s energy needs, to feed the brain and nervous system. Carbohydrates help to keep the digestive system fit and within calorie limits, and also help in keeping the body lean.
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Six sugar molecules are important in nutrition. Three of these are single sugars or monosaccharides (glucose, fructose and galactose). Glucose is the most important monosaccharide in the human body.
Effects
The impact of sugar consumption on health continues to be a controversial topic. There is evidence to suggest that diets high in added sugar promote the development of metabolic diseases both directly and indirectly. Directly, the fructose component in sugar causes abnormal regulation of lipid and carbohydrate metabolism.
Indirectly, sugar promotes positive energy balance, thus body weight and fat gain, which causes abnormal regulation.
When one eats (or drinks) a simple sugar, all of the ingested sugar quickly rushes into the bloodstream. There is quick increase in energy.
Additional insulin is released to remove the excess sugar. Therefore, for the moment, there is significantly lower blood sugar which causes a feeling of hunger and a feeling for more simple sugars, hence a sugar-craving cycle has been introduced.
As this continues, insulin becomes insensitive, blood sugar becomes high, and this may lead to diabetes. The satiety centre of the brain becomes damaged by insulin resistance, caused by the continuous high levels of insulin. Thus, weight gain becomes possible.
Other chronic metabolic diseases may also develop, which are collectively referred to as metabolic syndrome.
Consuming high amounts of fructose, which is a type of sugar found in fruits and vegetables, and other types of sugars from processed foods, activates this protein.
Fructose begins a process that causes the liver to keep producing glucose even as insulin tries to regulate blood glucose, thereby leading to diabetes. Other metabolic diseases may then develop.
Fat
Fat provides the greatest of the body’s energy and it is the body’s main storage form for the energy from food eaten in excess. Fats provide 80 to 90 per cent of the resting body’s energy and much of the energy used to power muscular work. Fats serve as an emergency fuel supply in times of illness and diminished food intake.
At nine calories per gram, fat contributes more calories than either protein or carbohydrate. It is, therefore, considered as being calorie dense. If a person eats a lot of high fat foods, the person is then consuming more calories in a small amount of food.
Also, much energy is not needed in converting and storing dietary fat as is needed to convert and store glucose or protein. Fat tastes good and so people may consume more of it.
Again, fat is broken-down into triglycerides and fatty acids. Fatty acids are burned for fuel. Fat enters and leaves fat cells as fatty acids. Glycerol provides the backbone needed to bind three fatty acids into triglyceride. It, therefore, determines the rate at which fatty acids become triglycerides within fat cells. If more glycerol can be made, more fat is stored in fat cells. More glucose will make glycerol available and in turn cause more fat to be stored in fat cells. As more fat is stored, the risk of getting metabolic diseases increases.
Fats can be classified as saturated or unsaturated. In general, unsaturated fats are accepted to promote good cholesterol and High Density Lipoprotein (HDL), while saturated fats are accepted to promote bad cholesterol and Low Density Lipoproteins (LDL).
However, recent studies have shown that there is no good or bad cholesterol. Majority of the cholesterol is produced by the liver and the brain is primarily made up of cholesterol.
Cholesterol is essential for nerve cells to function and is the basis for making all the steroid hormones, including oestrogen, testosterone and corticosteroids. High cholesterol in the body is a clear indication that the liver is in good health.
Eating foods that contain saturated fats raises the level of cholesterol in the blood.
Metabolic disorders
Inappropriate consumption of carbohydrates and fats is one of the factors that may lead to the development of some metabolic disorders.
A metabolic disorder occurs when normal chemical reactions in the body are disrupted. Metabolic diseases include diabetes, hypertension, obesity and stroke. Appropriate energy balance must be obtained to ensure the body works well.
This means that the consumption of every macronutrient must be equal to its breakdown. When this is disrupted, for example through overfeeding, the body tries to restore itself to its stable internal environment, and the speed at which each macronutrient is balanced has important complications for the role of diet in the regulation of body weight; as excessive weight gain or obesity is a risk factor for developing metabolic diseases.
Although sugar and fat are both essential, the quantities consumed must be taken into consideration to avoid overfeeding which may lead to the development of metabolic diseases.