The ice water hack is all over TikTok: drink ice-cold water, the story goes, and your body burns extra calories warming it up. Some versions go further and sell “ice hack” pills or powders. Here’s what research says about cold water and weight loss, and where the hype goes too far.
Key takeaways
- Ice-cold water raised calorie burn by only about 4.5% for an hour in one study, far too little to drive weight loss.
- Swapping sugary drinks for water does help, because water has no calories, the CDC says.
- In a 12-week trial, adults on a lower-calorie diet who drank about 2 cups (500 mL) of water before meals lost about 2 kg (4.4 lb) more.
Does the ice water hack work?
Not as a fat burner. In a 2006 study, ice-cold water raised energy use by only about 4.5% for an hour, and room-temperature water didn’t raise it at all. Water can still help with weight loss in simpler ways: it has no calories, and drinking it before meals helped people on a diet eat less.
What studies show about the ice water hack
The idea started with a 2003 study of 14 people, in which drinking 500 mL (about 17 oz) of water raised metabolic rate by 30%. That result made headlines.
A 2006 study tested it more carefully. Room-temperature water didn’t raise energy use at all. Water chilled to 3°C (37°F) caused only a small rise, about 4.5% over 60 minutes, which the authors said was well below the energy needed to warm the water. They concluded the results cast doubt on water as a way to burn calories for weight loss.
Where water does seem to help is appetite. In a 2010 trial, 48 adults aged 55 to 75 followed a lower-calorie diet for 12 weeks. Those who also drank 500 mL of water before each meal lost about 2 kg (4.4 lb) more. At the start, they ate less at a test meal after drinking the water.
Ice water hack claims vs evidence
| Claim | What studies show | Verdict |
|---|---|---|
| Ice water burns lots of calories | About 4.5% more energy use for an hour (2006) | Too small to matter |
| Water before meals helps you eat less | About 2 kg (4.4 lb) more weight loss in 12 weeks, alongside a diet | Worth trying |
| Swapping soda for water cuts calories | Water has no calories (CDC) | Helps |
| “Ice hack” pills melt fat | No good evidence; the FDA warns many weight loss products hide drugs | Red flag |
About “ice hack” pills and powders
Many “ice hack” ads are really selling supplements. The FDA warns that many weight loss products are likely to be contaminated with dangerous hidden ingredients, are sometimes falsely sold as supplements or all-natural, and aren’t guaranteed to work. They can lead to severe health problems and hospital stays.
The FDA’s advice: talk to a health care professional before buying or trying a new product for your health. A product missing from the FDA’s warning list isn’t proof that it’s safe.
Ice baths and cold plunges
Some versions of the ice water hack involve ice baths or cold plunges. Be careful. The US National Weather Service says sudden cold water can trigger gasping and fast breathing in the first few minutes, and a sudden spike in heart rate and blood pressure. Cold shock can be dangerous even in water at 50 to 60°F (10 to 15°C).
If you have a heart condition or high blood pressure, check with your doctor before trying cold plunges, and never do them alone.
How to use water to support weight loss
These tips come from the CDC:
- Choose water instead of soda, juice drinks, sweet tea and sports drinks.
- Carry a reusable water bottle.
- Freeze water in freezer-safe bottles if you like it ice-cold.
- Order water when you eat out, and serve it with meals.
- Add a wedge of lemon or lime for flavor.
You can also try a large glass of water before meals, as in the 2010 trial. If your doctor has told you to limit fluids, for example because of heart or kidney disease, follow their advice instead.
When to see a doctor
- Your weight changes a lot without a clear reason.
- You have a heart condition or high blood pressure and want to try cold plunges.
- You’ve been told to limit fluids and want to drink more water.
- You feel unwell after taking a weight loss pill or powder.
Frequently asked questions
Does the ice water trick work for weight loss?
The ice water hack doesn’t work as a calorie burner. A 2006 study found ice-cold water raised energy use by only about 4.5% for an hour. Water can still help if it replaces sugary drinks or if you drink a large glass before meals to help you eat less.
Does cold water burn more calories than room temperature water?
Only slightly. In a 2006 study, room-temperature water didn’t raise energy use at all, while water chilled to 3°C (37°F) raised it by about 4.5% over an hour. That’s far too little to matter for weight loss.
How much water should I drink before meals?
In a 2010 trial, adults on a lower-calorie diet drank 500 mL (about 2 cups or 17 oz) of water before each meal and lost about 2 kg more over 12 weeks. If your doctor has told you to limit fluids, follow their advice.
Is the ice hack a pill?
Some “ice hack” ads sell pills or powders, not just water. The FDA warns that many weight loss products may contain hidden drugs, are sometimes falsely sold as natural supplements and aren’t guaranteed to work. Check with a health professional first.
Are ice baths good for weight loss?
We found no good evidence that ice baths cause meaningful weight loss. They also carry risks: cold water can cause gasping, fast breathing and a spike in heart rate and blood pressure. Check with your doctor first if you have heart problems.
Is cold or warm water better for weight loss?
It barely matters. Cold water causes only a tiny rise in energy use. Pick the temperature you’ll drink more of, especially if it helps you skip sugary drinks. The CDC suggests freezing water bottles if you like it ice-cold.
The bottom line
The ice water hack won’t melt fat: cold water burns only a few extra calories. Water still helps weight loss when it replaces sugary drinks or comes before meals, and “ice hack” pills are a red flag. Drink water you enjoy and focus on steady eating and activity changes.
Related reading
- Lemon balm for weight loss: honest facts
- Natural Mounjaro recipe: does it work?
- Does sweating burn calories?
Sources
- Brown CM, et al. Water-induced thermogenesis reconsidered. J Clin Endocrinol Metab, 2006
- Boschmann M, et al. Water-induced thermogenesis. J Clin Endocrinol Metab, 2003
- Dennis EA, et al. Water consumption increases weight loss during a hypocaloric diet intervention in middle-aged and older adults. Obesity, 2010
- CDC: About Water and Healthier Drinks
- FDA: Weight Loss Product Notifications
- US National Weather Service: Cold Water Hazards and Safety