Gained 3 pounds overnight?
Find out the most of it that could possibly be fat. It takes 20 seconds, there's no sign-up, and nothing you type leaves this page.
Read the trend, not the day
One morning on the scale is mostly water and food in transit. What your body is really doing shows up in the trend over a couple of weeks. The Optimal app draws that trend for you, and explains every jump the morning it happens.
Get Optimal when it launchesQuestions people ask
Can you gain 3 pounds of fat overnight?Almost never. A pound of fat stores roughly 3,500 kcal, so 3 lb in a day would take more than 10,000 kcal beyond what you burn.
Why does the scale jump after a big or salty meal?Salt makes your body hold water, carbs are stored with about three times their weight in water, and food in transit weighs something. It usually settles in 2–3 days.
How does this tool work?It estimates what you burn from your weight, on the low side so the answer stays cautious, adds 500 kcal in case you ate more than you think, and turns the extra into the most fat it could be. Small jumps get no "that's not fat" claim at all.
The 3,500 kcal per pound figure is a rule of thumb. For how body weight really changes with energy, see Hall KD, What is the required energy deficit per unit weight loss? Int J Obes, 2008.