Although after eating a meal certain changes occur within the body they are:
After eating a healthy balanced meal the glucose levels within the blood will rise the reason for this is because the food in which you have just eating contains glucose, therefore the islets of langerhans within the pancreas release insulin to reverse the change. The islets of langerhans contain a small number of alpha cells and numerous beta cells, the alpha cells secrete glucagon where as the beta cells secrete insulin, this has an antagonistic effect on the blood glucose level within the body.
Insulin is a protein compose of 51 amino acids it is released within the body in response to a rise in blood glucose ( after eating a meal ). Insulin is carried the plasma and the receptor sites on the cell membrane bind it, this then leads to a change in both cell permeability and the activity of enzymes within the cell leading to the following effects occurring:
1. The conversion rate of glucose to glycogen will be increased ( glycogenesis )
2. Their will also be an increase in the rate of uptake of glucose by muscle and fat by cell membranes.
Therefore when we eat a meal the rise is detected within the blood glucose and the islets of langerhans within the pancreas release insulin to bring the levels back down by converting the glucose into glycogen which will then be stored in the liver. The reason for this is because glucose is soluble and is therefore easy to be carried around in the blood it also dissolves very quickly within the blood where as glycogen is in soluble and does not dissolve within the blood as it is stored in the liver until it is needed by the body. The excess glucose from the meal is converted to glycogen and stored in the liver.
If we have too little glucose in our blood the body will detect this change and glycogen will be released from the liver and converted into glucose, the reason for this is because the body is in need of more energy e.g. when a person has not eaten.
As soon as we start to eat a meal the digestion process occurs in the mouth, breaking the food down into small energy molecules that can be absorbed into the bloodstream. The bolus travels from your mouth down your esophagus and into your stomach, within the stomach the food is mixed and churned with digestive juices that are made up of acids and enzymes to ensure that the food is broken down into a liquid form, this can also be a paste like substance referred to as chime.
After being in the stomach for roughly 2 hours the food then travels to the small intestine this is where the most important part of digestion occurs as while the food is traveling through the ileum the nutrients, vitamins, minerals, proteins, carbohydrates and fats are absorbed by the villi and sent into the blood stream to ensure that they are delivered that need them.
The food that has not been digested then travels through the rest of the digestive system and into the large intestine. Within the large intestine water is removed from the food, therefore the waste is now in a solid form and travels into the rectum. The food will then be excreted from the body via the anus.
Glucose is the simplest form of sugar, it circulates in the bloodstream and is used by cells as fuel. Glucose is the primary fuel used by the brain and is stored in the liver and muscles as glycogen. All carbohydrates can be broken down into glucose in the body. Some carbohydrates have a simple structure that easily breaks down into glucose. These are simple carbohydrates, commonly known as sugars e.g. fruits, milk, and other foods, they are digested rapidly which allows the glucose to be absorbed into the bloodstream quickly. Therefore a meal that is high in simple carbohydrates can contribute to reactive hypoglycemia.
Complex carbohydrates and proteins are important in the diet. They are a basic source of energy. Complex carbohydrates are many molecules of simple sugars linked together like beads on a string. They take longer to break down in the intestine, and this helps to keep blood glucose levels more consistent. Pasta, grains, and potatoes are complex carbohydrates. Proteins are made of amino acids that the body needs for growth and good health. Most food protein can be converted into glucose by the body, but since this process takes some time, the glucose gets into the bloodstream at a slower, more consistent pace. That is why people with reactive hypoglycemia should eat complex carbohydrates and protein for their energy needs, instead of simple carbohydrates.