Does Drinking Cold Water Actually Burn Extra Calories?

The claim has circulated for years: swallow ice-cold water and the body burns calories just to warm it up. It sounds logical, and it makes a glass of ice water feel like a tiny workout.

The physics behind it is real. The question is whether the amount is large enough to matter, and the research gives a clear answer.

The Short Answer: Yes, but Barely

Drinking cold water does cost the body some energy, but the amount is small. Estimates run from a few calories to roughly 17 calories for a 500-milliliter glass, depending on how the math is done.

That’s less than a handful of almonds.

It won’t offset a snack, let alone a meal. The idea is true in a technical sense, which is why it survives, but the numbers explain why it hasn’t turned into a weight-loss strategy.

The Study That Launched the Claim

A widely cited study from the early 2000s found that drinking about 500 milliliters of water raised metabolic rate by up to 30 percent. The effect began within about ten minutes and lasted more than forty.

The researchers estimated a total extra burn of around 100 kilojoules, roughly 24 calories.

Those results spread widely and fed the idea of water as a metabolism booster. Later work, however, has questioned how large the effect really is.

The Math of Warming Water

The simplest calculation starts with heating. Bringing a 500-milliliter glass of near-freezing water up to body temperature takes about 70 kilojoules, which is around 17 calories.

That’s the theoretical ceiling for the warming alone.

Real bodies may not spend all of it. Researchers suggest some of the cost is offset by reduced heat loss elsewhere, such as blood vessels narrowing, so the real cost can be much lower.

What a Later Study Measured

A follow-up study put the claim to a tighter test. Eight healthy adults drank about 500 milliliters of distilled water, saline, or a sugar solution, and researchers tracked their energy use before and after.

Room-temperature distilled water did not raise energy expenditure in a meaningful way.

A smaller subgroup drank water cooled to about 3°C. Their energy expenditure rose by about 4.5 percent over an hour, only around 13 to 15 kilojoules, or roughly 3 to 4 calories. The authors questioned whether water could serve as a real aid for weight management.

Why the Real-World Gain Is So Small

Three or four calories is a rounding error in an ordinary day. Even using the larger estimates, drinking several glasses of ice water would add up to a modest number that is easy to erase with one bite of food.

The sums don’t hold up as a plan for losing weight.

Scientists also note that the studies were small and measured short windows. Individual responses vary, so it’s best to treat any calorie figure as a rough estimate.

Where Water May Help More

Water can still support weight goals, just not through temperature. Sipping water before a meal may reduce how much people eat. In one study of older adults, about 500 milliliters before breakfast cut that meal’s calorie intake by roughly 13 percent.

Swapping sugary drinks for water is another clear win.

Cutting a soda or sweetened coffee can remove far more calories than any thermogenic effect from cold water ever could. That’s a bigger, steadier change than chasing a few calories from ice.

So Which Temperature Should You Drink?

Whichever one you’ll actually keep drinking. Cold water is refreshing for many people, while others prefer room temperature or warm water, especially with meals or before exercise.

The best choice is the one that helps you stay hydrated.

If ice water makes you drink more, that’s a good enough reason to enjoy it. Just don’t expect it to move the scale.