The Underlining Mechanism of Weight Loss Induced by Bariatric Surgery (Weight Loss Surgery)

Before explaining the mechanism of weight loss induced by weight loss surgeries, it is necessary to explain that the present scientific concept about fat mass gain and loss is wrong.

In the articles: “Misconception about Counting Calories and Weight Management” and “Misconception about Energy Balance and Weight Gain-Weight Loss”, (Part 1, Chapter 1) there is an extensive explanation about the pseudoscience of weight gain/weight loss.    

The mechanism underlining weight loss induced by weight loss surgery can be explained by analysing the changes in body posture, and changes in walking gait that is induced by obesity surgery.

1)    Obesity surgery leaves a wound in the abdominal wall and a wound in the stomach.

2)    The abdominal wall wound heals in a matter of days, but the stomach wound takes much longer and in some cases, it fails to heal at all.

3)    Even when the stomach wound is healed, there are still staples or a band, depending on what kind of surgery is performed

The abdominal wall wound and the stomach wound, and later the staples or other surgical devices that is left in the stomach like lap band etc., forces patients to adopt a better body posture in a sitting position, otherwise they will experience discomfort or pain in the abdomen area.

Slouched or an extremely slouched posture in a sitting position decreases the size of the abdominal cavity and at the same time, it alters the shape of the abdominal cavity. The wound in the abdominal cavity and later the surgical devices, like staples, lap band, etc.; make the abdomen more sensitive to changes in the shape and size of the abdominal cavity.

Because of the wounds, the patient is forced to maintain an optimal size of the abdominal cavity; otherwise the wound will be compressed. When the stomach wound is compressed, the patient experiences increased strain or pain in the abdomen.

The optimal size of the abdominal cavity is possible to achieve only by maintaining a good body posture.

The optimal size and shape of the abdominal cavity is possible to achieve only by an optimal upward lifting activity of the abdominal muscles.


The abdominal wall wound and the stomach wound, and later the staples or other surgical devices that is left in the stomach like lap band etc. stimulate the upward lifting activity of the abdominal muscles.


a) In most cases, the patient doesn’t achieve an ideal correct body posture, but it is forced to maintain a much better body posture than before obesity surgery.

b) Improving the body posture positively affects the size and shape of the abdominal cavity.

The weight of the upper body (the part of the body above the abdomen) provides mechanical stimulation on the abdomen only in the case when it isn’t supported by the abdominal muscles. When the abdominal muscles support the upper body weight, the upper body weight doesn’t depress the waistline and abdomen, and that has the consequence that it doesn’t induce mechanical stimulations on the abdomen.

  1. The absence of mechanical stimulations is the factor that causes weight loss (regression of the bone, muscle and fat mass).
  2. A Contributing factor for weight loss after weight loss surgery is a reduced strength of ground impact forces.  [Any serious injury, whether it is caused by an accident or by surgery, forces a change in the walking gait].

The abdominal wall wound, the stomach wound, and later the staple or other surgical devices that are left in the stomach like lap band etc., forces patients to take more care of how he transfers his body weight from one leg to the other.

Before obesity surgery, the patient could walk while maintaining a more or less unbalanced walking and running gait (more or less clumsy gait).

After obesity surgery, walking with an unbalanced gait will produce discomfort or pain in the abdomen. The wound in the abdomen, later the staples or lap band, forces the patient to walk in such a way that he transfers the body weight from one leg to the other in a more balanced way then before weight loss surgery.

The wound in the stomach forces the patient to perform a more efficient locomotion than what was the case before obesity surgery,  and after the wound heals the staples, lap band etc. that is left in the stomach or in the abdominal cavity, forces the patient to perform a more efficient locomotion than what was the case before obesity surgery.

  1. The gait improvement causes an improved efficiency of walking (efficiency of locomotion).
  2. The improved efficiency of locomotion causes reduced strength of the ground impact forces.
  3. The reduced strength of impact forces causes reduced strength of the mechanical stimulations.
  4. Reduced strength and/or duration of mechanical stimulations below the level necessary for maintaining the existing body mass will result in the loss of muscle, bone and fat mass.

To fully understand the mechanism underlining weight loss induced by Weight Loss Surgeries, it is necessary to know a little bit about mechanical stimulation.

In weightlessness, the human body is exposed to almost a complete absence of mechanical stimulation, because in weightlessness the body does not have weight and there is no ground impact force.


On Earth, the human body is exposed to four types of mechanical stimulations.

1. Mechanical stimulations – type 1 are produced by the weight of the body.

The human body is exposed to mechanical stimulation type 1, while lying down, sitting and for the time of performing locomotion, like walking, running, jumping, etc.  

2. Mechanical stimulation – type 2 are produced by a ground impact force that appears each time when we transfer the weight of the body from one leg to the other.

To get the idea of what the ground impact force is, it is enough to hit the ground with the bottom of the feet and you will feel how the impact force transmits from the bottom of the feet throughout the rest of the body.

By observing overweight or obese people when they walk or run, we can notice that by transferring the body weight from one leg to the other they, to some extent, fall from one leg to the other like they are stepping harder on the ground with their feet, and that has the consequence of producing stronger ground impact forces.

a) When soldiers are marching, they strike the ground with their feet. But there are huge differences between a soldier’s march and an unbalanced gait. While marching, the soldiers use their bones and muscles to strike the ground and at the same time, to propel themself from one place to another by transferring their body weight from one leg to the other.

b) A simplified explanation of what happens while walking with an unbalanced gait would be; the weight of the body strikes the ground by falling from one leg to the other.

3. Mechanical stimulations – type 3 is produced by the jiggling of fat tissues.

Usually, mechanical stimulations – type 3 is a side product of the impact force combined with movement of the body parts. Among extremely obese people, it is noticeable that even when they are in a lying down position, that by each movement of any parts of the body, like moving the arm, it produces a jiggling of the fat tissues.

By simply observing obese people when they are walking, it is visually noticeable how their fat tissues are jiggling with each step they make.

4. Mechanical stimulations – type 4 are induced by the compression of muscles and fat tissues.

For example; rolling the pelvis fully backwards will reduce the vertical size of the waistline. Due to this reduced size, the abdominal muscles and fat tissues are compressed.