Why we don't drink with meals ...

UPDATED -- This post has been updated with a re-write on May 14, 2010.

After Weight Loss Surgery we are given many new and unusual rules that we must abide by for the rest of our lives. But the idea that we must change the way we think about a behavior forever can be daunting. Sometimes understanding why the rule exists helps us to be more compliant with these new rules.


The Rule
No drinking with meals or for 30 to 60 minutes after a meal (this includes snacks too). In this article we’ll explore the reasons why this rule is so important and what happens when we don’t follow the rule.


The Old Anatomy
First, let’s understand how our old stomach used to work. Before Roux-en-Y Gastric Bypass Surgery you had a normal stomach with a pyloric valve at the bottom to keep food inside the stomach while it began the digestive process.

The stomach is a powerful muscle that contracts around the food in a churning motion. The stomach release gastric acid (made up mostly of hydrochloric acid) to further break down food as it’s churned. As food is broken down enough the pyloric valve (a trap door, really) opens to let some food particles out of the stomach and into the small intestine. This churning process continues and the pyloric valve will keep opening and closing as more food is prepared for release. This process can take 2 to 3 hours in a normal stomach. It’s much different after Roux-en-Y gastric bypass surgery.


The New Anatomy
After RNY the pyloric valve is no longer part of the newly formed pouch. It remains at the bottom of the stomach which is bypasses, so we will never use the pylorus again to control the flow of food from the stomach to the small intestine.

Our new stomach pouch is shaped like a funnel. Which is a larger bowl shape at the top with a small narrow opening at the bottom. The food we eat is held in place in the larger upper portion of the funnel and gravity allows food to slowly flow out the lower narrow opening at the bottom of the pouch. That narrow opening is called the anastomosis or “stoma” for short.
With our new pouch we have to mimic the action of the pyloric valve manually and the only way to keep food in our pouch is to eat dense foods and not mix it with liquid.


The Food
The more dense the food, the longer it can stay in the pouch. The softer and more liquid the food, the sooner it will empty from the pouch. Dense food can stay in your pouch for 1.5 to 2 hours if you don't drink water. But the moment you add water (or any liquid) to the pouch, you are creating a "soup" that will quickly empty out of your pouch.

Soft foods that slide straight through the stomach pouch are called “slider foods” and include things like yogurt, soup, pudding or ice cream. Although these are good foods to consume in the early stages after surgery, be careful not to get into the habit of using slider foods as your main food source.

Of course when your pouch is empty you’ll get hungry sooner. For new post-ops, this isn’t a major concern because the hunger hasn’t returned fully. But for those further out from surgery, the hunger can be ravenous for some and the primary way to stave off hunger is to keep food in the stomach pouch for as long as possible. This is why it’s recommended that the further out you are from surgery, the longer you wait to begin drinking after meals (60-90 minutes).



The New Digestive Process
About 40% of the digestive enzymes required to fully break down simple starch-based carbohydrates is contained in our saliva (known as ptyalin). To break down complex carbohydrates, protein and fat, our body requires the addition of gastric acid and other digestive enzymes normally produced in the stomach. But our new stomach pouch does not produce in any significant amount of gastric acid or enzymes. This is one of the main reasons why we need to chew, chew, chew really well.

Once food gets to the pouch, the digestive enzymes from our saliva and the limited amount produced by the stomach go to work on the food to begin breaking it down. Our pouch doesn't churn as much as our old stomach used to, but there is still some movement with that well-chewed food.

The longer food stays in the pouch, the more it is broken down and prepared for the intestines to do their work of grabbing micro and macro-nutrients from the food. If we wash the food out too quickly a few different things happen. First, if food is not properly prepared for optimal absorption (chewed well, mixed with enzymes) we risk having food move too quickly through our digestive track without the benefit of full nutrient absorption. Second, if food is not well chewed or broken down, we are also at greater risk for intestinal blockages or constipation.



The Other Big Risk
There's also the risk of stretching the stoma (the opening between the pouch and intestines). If you have dense food that has not yet begun to be digested in the pouch and you drink water you are forcing dense food through the stoma prematurely. The opening is only about the size of a lady’s index finger, but if you habitually push food through the opening before its ready to go, you'll eventually stretch the stoma. This is far more worrisome than stretching your pouch. Once the stoma is stretched it can become the same diameter as the pouch itself. This would essentially create one big long tube that food can be packed into at meals. Need a visual? Stretching your stoma would give you a 20-foot long stomach.

This caution from surgeons is not a scare tactic. This rule is about biology and medical science because now you have to manually do the work of the pyloric valve that has been bypassed. By following this rule for the rest of your life, you’ll properly prepare your food to give your body the best chance of absorbing the vital nutrients it needs for survival as well as achieve the level of satiety needed to reduce hunger between meals.

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This article can be downloaded as a PDF.

Check out this video from Former Fat Dudes - a visual lesson!