Tuesday, January 12, 2010

A Question About Water and Weight Loss

3) Why is water so important for weight loss?

Actually, it isn’t. The only thing water is important for is to help us stay hydrated. Yes, there are many diets out there or statements in general that claim we must consume anywhere from 6 to 8 eight ounces of water a day. This is fine as it helps prevent dehydration, which helps our kidneys to function, helps to maintain an appropriate blood pressure, provides the aqueous medium our tissues need to allow our electrolytes to work properly (electrolytes refer to sodium, potassium, magnesium, chloride, bicarbonate etc.).

But it must be emphasized that one can consume too much water. Unfortunately we live in a society where if a little is ok, then more is better. I more than occasionally have a patient who I have to admit to the hospital due to water intoxication. In this clinical scenario, the person has actually drunk too much water. When someone over consumes water, it will dilute out and cause a lowering of the important electrolytes as mentioned above.

The one electrolyte that appears especially vulnerable is sodium. When sodium levels are low this is referred to as hyponatremia. This is a very serious condition. The person who is experiencing hyponatremia will present with the appearance of being intoxicated on alcohol, they may have seizures, and they will certainly feel weak and confused. This is a condition that requires hospitalization to correct, and deaths have resulted from improperly raising the sodium level too quickly. A condition known as central pontine myelinolysis (CPM) can occur which is basically a disruption of the central nervous system function, with seizures and death possibly a result.

Now the consumption of water before a meal, it has been said, fills up the stomach, giving you a fuller feeling before you eat. The theory is that if you have a fuller feeling before you eat, well, you’ll tend to eat less. A simple understanding of physiology will help dispel this myth. When we consume liquids, they will pass into and out of the stomach a lot more quickly than solids. This is because some digestion of solids does occur at the level of the stomach, mainly with a protein meal, but the stomach also helps digestion of non protein solids as it has a ‘grinding/mashing’ effect on solid food, helping in the digestive process. The more ‘mashed’ up the solid food is before it arrives at the small intestine, the easier it is for digestive enzymes to work.

Since liquid passes pretty quickly into and out of the stomach, the full feeling does not last all that long and the person will start feeling hungry again, sooner than they thought. And yes, they will most likely overindulge hindering efforts at weight loss. Especially if they're not eating low carbs.

dr jim

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