Body weight normally varies by a few pounds a day from water and food. A swing of 10 pounds in a day is unusual, so check your scale, and see a doctor if you have swelling.
Normal
Body weight varies 2 to 5 pounds a day from food, water, salt and bathroom visits.
10 pounds
A 10 pound change in a day is much larger than normal and suggests fluid shifts (or a scale or timing error).
Possible causes
- Heart failure.
- Kidney disease.
- Liver disease.
- Medicines.
- Extreme water or salt intake.
What to do
Weigh at the same time under the same conditions.
See a doctor
Promptly, especially with swelling or breathlessness.
What counts as normal
Body weight can change by 2 to 5 pounds (1 to 2.3 kg) in a day from water, food and waste. A drop or rise of 10 pounds in a day is not fat change, since a pound of fat represents about 3,500 calories. A true 10 pound change in a day from fat is not possible, so it’s water or a measurement issue.
- Salt, carbohydrate intake, hormones (menstrual cycle), alcohol and exercise change water weight.
- Weigh under the same conditions each day, such as after waking and using the toilet.
- Medicines such as steroids, and conditions such as heart failure, kidney disease or liver disease, cause fluid retention.
When to check
Rapid weight gain of 2 to 3 pounds in a day or 5 pounds in a week in people with heart failure should prompt a call to their doctor. Swelling, shortness of breath or reduced urine output with weight gain needs medical attention. A scale error is possible, so check on a flat hard surface and with a different scale. Track weekly averages instead of daily numbers.
What counts as normal
Daily weight can vary 2 to 5 pounds due to water, salt, food in the gut and hormones. A 10 pound swing in one day is unusual and may come from large salt and fluid shifts, dehydration, illness or measurement errors.
When to check
Rapid weight gain with swelling or breathlessness can signal heart or kidney failure. See a doctor if changes are rapid and unexplained.
Causes of large swings
Glycogen binds about 3 g of water per gram. Salt intake, carbohydrates, alcohol, menstrual cycle and bowel contents can shift weight several pounds. A very large meal weighs the same as its food, including water. Scale errors and different clothing add noise. Weight can differ by 1 to 2 percent during the day.
Tracking correctly
Weigh at the same time each morning after using the bathroom, before eating, and use a weekly average. True fat gain of 10 lb in a day is impossible since it needs 35,000 surplus calories. Medical causes of fast weight gain are fluid retention from heart, liver or kidney disease and medications such as steroids. Seek help for gain of 3 pounds in a day or 5 in a week with swelling.
Based on data from the Mayo Clinic and the American Heart Association
