Eating is at best our simplest urge, and is body’s most complex process.
Blood sugar, energy levels, hormones, daily bodily functions, and even our evolutionary past play a part in stimulating or suppressing our eating desires. Excessive weight gains can partially be explained by a reward system that is rooted in hunters-gatherers.
Researchers claim that our brain places a premium on high-calorie foods, storing up for times when food was in short supply..
In prosperous societies, such times never come.
The brain (although it weighs on average less than 1 ½ kilograms consumes 20 – 25 per cent of our oxygen supply and 15 per cent of our blood flow.
We all eat, as we must, but only a few of us think what actually happens between the first bite or drop of liquid of anything we ingest, and the final exit.
We eat when hungry, although many people eat at regulated times, even if they are not hungry. Aboriginals eat only when they are hungry. We feel hungry when ghrelin (an amino acid, peptide, and hormone in the stomach and pancreas) stats to increase in the stomach (generally at established times or when the stomach is empty).
The gastrointestinal tract consists of the esophagus, stomach, and duodenum, including both the small and large intestines.
Digestion is the mechanical and chemical breakdown of food into the smaller and more digestible components for easy absorption into the bloodstream
The process starts with mastication, which is both mechanical and chemical. Saliva, which contains amylase (an enzyme) breaks down starch, and eventually converts it to sugar.
Teeth (represent approximately 6 – 6 1/2 square centimetres of surface) are the grinders and must be kept in good working order with meticulous daily brushing and regular maintenance. (Two to three times annually of thorough cleaning by a qualified technician is recommended).
In the mouth food is formed into slurry in the form of a ball, called bolus, and which travels through the esophagus by means of peristaltic movements to the stomach.
Thorough chewing is an important part of digestion.
The gastric juices (gastric juice has a pH value of 1 – 2 and denatures proteins, making it possible for mucus to control pepsin over development) in the stomach start the process of digestion. They contain hydrochloric acid (hydrochloric acid is a clear, colourless, highly corrosive, strong mineral acid found in gastric juice, and is manufactured for a variety of industrial uses), and pepsin.
To protect the stomach walls, mucus is injected into the stomach, as hydrochloric acid is corrosive and very strong.
The stomach agitates the food and turns it to a thick liquid called chyme; that in turn enters the duodenum.
Here, digestive enzymes from the pancreas enter the process.
From here the food passes to the small intestines where 95 per cent of the nutrient absorption into the blood occurs.
After approximately one hour, 50 per cent of the food consumed (pending texture and fibre content) goes into the intestines. Eating refined food with little fibre content, renders intestines lazy, causing constipation that may lead to all kinds of diseases including cancer of the colon.
The total transit through the colon takes anywhere between 12 – 50 hours with wide variations between individuals, and type of food consumed.
The digestive system is very complex and must be protected to the extent possible in an attempt to make it function flawlessly and as long as possible. This is only possible by choosing your food carefully, cooking it expertly, and eating on time at regular intervals.