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The digestive system  metabolism and weight 1

The Digestive System, Metabolism and Weight

Therefore, obesity is the result of long term energy imbalances, wherein daily energy intake exceeds daily energy expenditure

Let’s explain how the digestive system works while you eat, and put it into context considering weight gain. According to research, the primary purpose of hunger is to increase the probability of eating. The primary purpose of eating is to provide the body with the chemicals and energy needed for survival and proper function. Once we eat food, it is absorbed into the gastrointestinal tract. Digestion is the process of breaking down food and absorbing its constituents into the body.

The digestive system is made up of the gastrointestinal tract, liver, pancreas and gallbladder. First, the food gets chewed in the mouth and mixed with saliva. Our saliva starts to break down the food, and lubricates it for further ingestion. Then it goes from the oral cavity, through the esophagus, and into the stomach. The hydrochloric acid in the stomach dissolves the food into small particles. Pepsin begins the process of breaking down protein molecules into amino acids. Digestive enzymes in the duodenum continue the protein breakdown. It also converts starch and other complex sugars into simple sugars. Simple sugars and amino acids pass through the duodenum wall into the bloodstream and are carried to the liver. Fat cannot pass directly through this wall.

However, it goes through small ducts in the duodenum wall into the lymphatic system. The remainder of water and undigested food is ejected from the body. Extrinsic and intrinsic nerves help to control the digestive system: Extrinsic nerves release chemicals that cause the muscle layer of the GI tract to either contract or relax. Intrinsic nerves release many different substances that speed up or delay the movement of food and secretion of digestive juices.

Bacteria and weight

Recent research has shown that a specific mix of bacteria found in the digestive system of obese people might make them prone to gaining weight. It’s likely that these people have a larger number of digestive microbes efficient in extracting calories from food. This kind of bacteria leads to weight gain.

Check with your doctor should you feel or observe any cause for concern; this ensures that your digestive system is doing fine.


As a result of digestion, the body gets energy in three different forms: lipids (otherwise known as fats), amino acids and glucose. Since the body always requires energy but doesn’t constantly receive it, it needs to store it in-between meals. Energy is stored in three forms: fats, glycogen and proteins. Most of it is stored as fat. We can deduce that fat plays the role of reserve energy. Changes in body weight are mostly the consequences of changes in the amount of body fat.

''It’s important to spend more energy than you put into your body, should your goal be to lose weight''

There are three phases of metabolism of energy. The first is the cephalic phase and it starts when we see or smell food. Our insulin levels go up as we do so. The next one is called the absorptive phase. Nutrients gets absorbed while in this state. They satisfy our immediate energy needs, while the rest gets stored. The last phase, called fasting, is important for weight loss. By that point, all the unstored energy got used, leaving the body to its reserves. Your body will take energy from those reserves of fat, as long as you stay in this phase.

People often go directly from one absorptive phase into the next cephalic phase throughout periods of rapid weight gain. This occurs without allowing time for a fasting phase. Therefore, obesity is the result of long term energy imbalances, wherein daily energy intake exceeds daily energy expenditure.

It’s important to spend more energy than you put into your body, should your goal be to lose weight. Of course, it’s not necessary or advisable to starve yourself for long periods of time. It’s enough to use just a little bit more energy than you consumed throughout the day. That way you’ll less likely feel hungry while losing fat in a healthy manner.