If you’re trying to lose weight, you’ve probably already replaced sugary drinks, like soda and juice, with water.
But scientists are beginning to get a better picture about the role that drinking water plays in weight loss. And it’s leading to some interesting observations about how it impacts our feelings of hunger.
A new study being presented this week at the Society for the Study of Ingestive Behaviour looked at how different amounts of water interacted with the brain.
In the small study, researchers at the Wageningen University in the Netherlands looked at 19 healthy men and gave them all a meal shake. That was followed by either 50 milliliters of water (about a shot glass worth of water) or 350 milliliters of water (roughly the amount of a can of soda). The researchers then looked at MRI scans to see how the liquids affected the stomach and brain.
Of those who drank more water, the participants’ hunger was more suppressed and they felt more full than those who only had a gulp of water. They also noted more brain activity in those who had drank more water after their shake.
This is also not the only study to find these kinds of connections with drinking water around mealtime.
Drinking water before or after meals
Alternatively, studies have looked at what would happen to people’s weight loss if people drank water before eating. In a small 2015 study, researchers at the University of Birmingham found that, on average, people who drank water 3o minutes before some or all of their three meals a day lost between 5 and 9 pounds over the course of about three months.
For their study, researchers at the University of Birmingham looked at 84 people (54 women and 30 men) who were on average 56 years old. About half the participants drank 16 ounces (roughly two glasses) of plain, noncarbonated water 30 minutes before at least one meal a day. Some people ended up drinking water before all of their three meals a day, while others just did it for one or two.
To figure out if they were sticking with the plan, the researchers periodically surveyed the participants and monitored their urine to see how much water they were actually consuming.
The other half of the participants didn’t drink any water before their meals. Instead, to encourage them to feel like an active part of the study, they were told to picture feeling full.
Overall, both groups of study participants lost a bit of weight — between 2 and 9 pounds — over the course of the study. Researchers can’t say for sure why this happened, but several studies have found that simply being studied can have pronounced effects on behaviour.
But people in the water-drinking group lost about 2.7 pounds more than the group that did not change their water-drinking habits.
Why would water make a difference?
There are many factors that can contribute to weight loss, from an increase in exercise to a change in diet or mood.
The researchers in the Birmingham study tracked some of these factors over the course of their study, including participants’ physical activity and how many calories they ate at each meal.
They noted that there wasn’t much of a difference between the two groups in terms of how much they exercised — in fact, the group that wasn’t drinking water before meals actually worked out a little longer, on average, than the group that did drink water.
What likely contributed to the weight loss, therefore, wasn’t exercise, and it wasn’t necessarily changes in the contents of the participants’ meals. They were given general nutrition tips, but they were instructed to eat whatever they wanted.
Yet the people in the water-drinking group ate fewer calories at each meal than the people in the group that didn’t change their water-drinking habits.
The researchers thought that this decrease in calories at each meal could be chalked up to the obvious: Drinking water fills up your stomach, making you feel more full and less hungry.
The results from the Wageningen University study seem to back this up: Those who drank more water reported feeling more full and less hungry, and imaging showed more full stomachs.
Considering trying the ‘diet’?
While this might have been the case for the participants in the study, other research has found that people continue to eat even when they feel full, so it might not be a foolproof plan for everyone.
Plus, the study sample included mainly white, middle-aged adults who are men, so the “results may not be applicable to a general adult population.”
So, in everyday life, drinking water to manage weight might fit in better as an addition to an overall healthy lifestyle, as opposed to being used on its own.
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