Dr. John Day, Cardiologist

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How to Lose 10 Pounds with Water Preloading

“I just can’t seem to lose any weight,” Holly said at her last cardiology clinic visit.

“Are you drinking enough water?” I asked.

“I’m lucky if I can drink a glass or two of water through the day,” she replied.

Could water preloading be the secret for Holly to overcome her weight loss challenge?  In this article I share the new science behind water preloading and how it can help you to maintain a healthy weight for your heart.

What is Water Preloading?

Water preloading is really just the process of hydrating prior to every meal. Water preloading may help with weight loss because it stretches the stomach.  This mechanical stretching of the stomach shuts down ghrelin release.  With the hunger hormone ghrelin suppressed you will be less likely to overeat with your meal.

What is the Science Behind Water Preloading?

While many people have intuitively known that hydrating before a meal helps them to control their appetite, until recently there were no solid scientific data supporting this practice.  Fortunately, the study has now been done.  In this well-designed scientific study, Dr. Helen Parretti and colleagues from University of Birmingham showed effortless and significant weight loss with the simple act of water preloading.

To come to this conclusion, researchers enrolled 84 obese people and then randomly divided them into two groups.  The water preloading group was told to drink 500 mL, or 2 cups of water, within 30 minutes prior to eating each meal.  In contrast, the control group was told to imagine that their stomach was full prior to eating.  Interestingly, these study participants had no idea why they were doing what they were told to do.

Without even trying to lose weight, the water preloading group had lost an average of 5.3 pounds (2.4 kg) whereas the imagine your stomach is full group lost a mere 2.6 pounds (1.2 kg).  The results are even more impressive if you just look at the results of the people who actually did what they were supposed to do in this study.  Specifically, those who were 100% faithful in water preloading before each meal lost 9.5 pounds (4.3 kg)!  Equally impressive was that 27% of the water preloading group were able to lose enough weight to get down to their target body weight from water preloading alone.

Thin People Drink More Water

A separate line of evidence in support of water preloading is that there have now been many studies which have shown that fit people tend to drink more water.  Indeed, one study showed that water drinkers, on average, consumed 194 less calories each day.

It is unclear as to why fit people drink more water.  It is possible that by drinking water they are not drinking sugary or diet drinks.  Alternatively, drinking water may be allowing them to control their appetites.  Equally possible is that fit people drink water for cultural reasons as that is what healthy people tend to do.

Should You Try Water Preloading?

Given than about half of all Americans drink less than 4 cups of water each day, the simple answer would be “yes,” for most people.  Interestingly, in this report from the CDC, the same people who don’t drink enough water are also the same people who choose unhealthy foods.

The water preloading protocol of this study resulted in just 6 cups of water in a day.  This is still less than the 8 cups of water recommended by many healthcare providers.

For 99% of the population, there is little downside in drinking 2 cups of water before each meal.  Even if you don’t lose weight, if you are like most water deprived Americans, then drinking more water will probably result in other health benefits.

Will water preloading work for everyone?  Probably not.  However, if the results of this small study are true, then water preloading could result in a quick 10 pound weight loss over the next 3 months for you.

I must confess that since reviewing this study I have been very diligent in water preloading before each meal.  Whether it is a placebo effect or not, I have noticed that I don’t need to eat as much food to feel full.  Placebo effect or not, it is nice not feeling as hungry through certain parts of the day.

Who Shouldn’t Do Water Preloading?

If you are considering water preloading, and you do not feel well or are being treated for any medical condition, you should speak with your physician first.  For example, 500 mL of water prior to each meal is enough fluid to cause someone with heart failure to quickly become short of breath from fluid retention.

What has been your experience with water preloading?  Please leave your comments below for our community.