Gastric Bypass Success, But No Surgery

Gastric bypass or bariatric surgery has been touted as a reliable way to finally help morbidly obese people get their weight down to a healthy level — and as a result of its rising popularity, some people may see gastric bypass as an "easy way out". 

Gastric bypass is, however, a major surgical procedure which can be hazardous and associated with serious complications. It is therefore seen as the last resort in a person’s battle to reduce their weight, a step to be taken only when conventional dieting and exercise has not been successful. To be considered for the procedure, people must exceed a certain body mass index (usually 40 or more) or have a medical or physical condition seriously negatively affected by their excessive weight.  

What is gastric bypass surgery?

The procedure consists of reducing the size of the stomach to a much smaller size. While the human stomach is normally about the size of a closed adult fist, gastric bypass surgery reduces it to around the size of a chicken egg. The part of the intestine located immediately beyond the stomach is usually bypassed during the procedure, making the gut shorter and limiting the absorption of nutrients from digested food.

Effect of bariatric surgery

The primary intention of the surgery is to physically restrict the quantity of food which people can eat at any one time, to prevent over-eating. Bypassing the part of the gut where most absorption of nutrients takes place also helps reduce weight by limiting the calorific (energy) value of any food that is eaten.

Is gastric bypass effective?

In some people, this procedure is so effective that they start to lose weight immediately after the surgery, and weight-related conditions, such as diabetes, have been known to improve before any weight has been lost. Some people find it no problem adjusting their food intake following surgery, despite a lifetime of over-eating, and lose weight easily. After the initial adjustment period, some people discover that the procedure allows them to maintain a healthy weight indefinitely.

It’s our brains which tell us when to stop eating

It has been known for a long time that eating behavior is controlled by complex interaction between hormones and nerves acting between the stomach and brain.  We all know that when our stomach is empty, our brains tell us to eat something and it makes sense that conversely when we eat a good meal our brains shut down our desire to eat more. 

More recent research has partly uncovered the particular parts of the brain, nerve pathways and hormones involved in this process. It has been found that nerve signals are sent to the brain from the stomach in response to food. 

It’s thought that the signal to stop eating is given in response to the calorific value of the food being absorbed. If the calorific value is low more food can be consumed before the signal is given.  

Clearly these signals are important to guide our eating – so that we eat sufficient amounts, but do not eat too much at a time. (It is thought that if there is too much food in the stomach it is not absorbed properly).

We can, of course, choose to ignore those signals to stop eating if we wish — and decide to keep eating anyway. But in the case of obese people, it appears that those signals are very weak or absent, making it difficult for them to know when they should stop eating. 

Limiting Meal Size Is Not The Only Effect

It is now felt that the effect of bariatric surgery is not just as a result of reducing the size of the stomach. It appears to restore the lost effect of the brain on appetite control – known as satiation.

What difference will these findings make?

The first is that once the mechanisms are fully understood, ways of influencing them – other than by surgery – may be found. 

Why would this be a good thing?

Gastric bypass surgery is an extreme measure and not without risks. Performing such surgery on obese people, or those with conditions like diabetes increases the general risks of surgery. People can develop serious infections in the abdomen (peritonitis), or blood clots (venous thrombi) which travel to the lungs (pulmonary emboli) and can be life-threatening.

Also, following surgery, because the absorption of nutrients is reduced by bypassing part of the intestine, people can become malnourished and develop anemia or osteoporosis. They will need to take food supplements for the rest of their lives. Other complications included kidney stones, gall stones, hernias and nerve damage.

What are other benefits of these findings?

There is no doubt that gastric bypass surgery is very effective in some people, but there is a group of people in whom it does not work, who expose themselves to the risks for no gain. 

Researchers believe this might have something to do with the signals between their stomach and their brain. So once this is better understood, it might be possible to predict those for whom bariatric surgery will be of no benefit – saving them from the risks of surgery and the subsequent disappointment of it failing.

Andrew Hajnal, professor of neural and behavioral sciences, who was part of the research said:

Are there other new approaches to appetite control?

Yes, as well as being under nerve control, as mentioned earlier for some time it has been known that hormones produced by the digestive tract also influence satiation.

But as more is known about the effects of these hormones and how they influence appetite, it might be that in the future they will be produced by pharmaceutical companies and administered as a medicine to help people who struggle to control their weight.