If you're trying to lose weight, you've probably already replaced sugary drinks with water.
But what you might not be aware of is that drinking water before meals could be helpful for weight loss — and perhaps not just because it occupies space in your tummy.
In a small recent 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 2.5 and 4 kilograms 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). The researchers don't provide the age range for the participants in their paper, but they do say the average age of the participants was 56 years.
About half the participants drank 450 millilitres 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 behavior.
But people in the water-drinking group lost about 2.7 pounds more than the group that did not change their water-drinking habits.
How did this happen?
There are many factors that can contribute to weight loss, from an increase in exercise to a change in diet or mood.
The researchers 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 think that this decrease in calories at each meal could be chalked up to the obvious: Drinking water fills up your tummy, making you feel fuller and less hungry.
But there could be other reasons as well. For one thing, when you're dehydrated, your body will often tell you you're hungry, so there's a better chance of water getting into your system through the food you eat.
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 this might not be a foolproof plan for everyone.
Plus, the study sample included mainly white, middle-aged adults, so the "results may not be applicable to a general adult population."