Can Drinking More Water Really Help You Lose Weight?
We all know exercise burns calories—but did you know drinking water can, too? The surprising science behind water temperature and metabolism might change how you hydrate.
“Exercise, exercise, exercise.” When it comes to burning more calories (officially known as increasing energy expenditure), exercise tends to steal the spotlight. But as we discussed in last week’s Ajenda, your body has other ways of torching calories—no gym required.
One that I rarely see talked about? The thermic effect of food, which is the energy required for your body to digest what you eat and drink. The question becomes: Is there a way to strategically use this process to burn more calories?
Short answer: Yes! And it can be as simple as reaching for your water bottle. Let me explain:
How Drinking Water Leads to Burning Calories
Out of all the foods and beverages we consume, water is the best one to leverage our body’s machine (to get more metabolic bang for your nutritional buck, so to speak).
For starters, it’s known that water can activate the stretch receptors in your stomach, which triggers signals to your brain saying you’re ‘full.’ These satiety signals, driven by the hormone leptin, help regulate appetite and curb how much we eat.
And the impact goes beyond just feeling full. A study by Popkin et al found that people who regularly drink water consume about 9% fewer calories per day—roughly 194 calories less—compared to those who don’t. That’s a big payoff for a small habit!
Here’s some more science-backed evidence: Another study by Jeong (2018) in Clinical Nutrition Research discovered that non-obese people who drank as little as two cups of water (500 mL) consumed fewer calories than those who didn’t.
Woah. How Does This Work?
Honestly? We still don’t fully understand how this process functions.
One theory is that it’s linked to delayed gastric emptying—the same mechanism behind GLP-1 drugs such as Ozempic and Semaglutide. Another possible factor is the reduced secretion of motilin, a hormone that keeps the digestive tract moving.
So far, we’ve covered the what (water), why (it triggers stretch receptors in the stomach), and when (best before a meal). But what about the how? Specifically, does the temperature of the water matter?
It turns out, interestingly, that research suggests it does!
The Optimal Water Temperature For Weight Loss
When it comes to burning calories, colder is better! Let’s go back to a high school or college chemistry class to understand why.
First is basic thermogenesis. When we consume something colder than our body temperature, we need energy to warm it up so it’s thermo-neutral (a fancy way of saying identical to our core body temperature). In other words: The colder something is, the more energy it requires.
Now that we know that, what does the science literature say?
A 2019 study by Fujihira et al. published in the European Journal of Nutrition found that in a group of 11 healthy young Japanese men, drinking 500 mL of water at 35.6°F (2°C for my non-American readers!) suppressed gastric contractions and reduced energy intake compared with those who consumed 500 mL of water at 98.6°F (37 °C) and 140°F (60 °C).
And the effect was significant—those who drank cold water consumed 19% fewer calories than the 98.6°F group and 26% fewer than the 140°F group!
Of course, more research on a large scale is needed—especially with women of all ages. But as of now, there’s sufficient published data for me to safely recommend drinking cold water before a meal.
The extra calorie burn won’t likely be a huge amount, but over time, every little bit can add up. Ice ice, baby! ❄️
