The fastest way to get ketones out of your urine is to drink more water and eat enough carbohydrates so your body switches back to burning glucose instead of fat. Ketones appear in urine when your body breaks down fat for fuel, and clearing them requires addressing that underlying shift in metabolism. How quickly they disappear depends on why they showed up in the first place.
Why Ketones Show Up in Urine
Your body prefers glucose as its primary energy source. When glucose is unavailable or your cells can’t use it properly, your liver starts breaking down fat instead, producing ketones as a byproduct. Your body can’t tolerate large amounts of ketones, so it tries to flush them out through urine.
The most common reasons ketones appear in urine include eating a very low-carb or ketogenic diet, prolonged fasting or skipping meals, intense or prolonged exercise, vomiting or diarrhea that lasts a long time, pregnancy, alcohol use disorder, and eating disorders or starvation. For people with diabetes, ketones often signal that insulin levels are too low to move glucose into cells, which forces the body to burn fat even when blood sugar is high.
Drink More Water
Hydration is the single most effective step you can take right away. Water helps your kidneys flush ketones out faster. When ketone levels are at the trace or small stage (under 20 mg/dL on a urine test strip), increasing your fluid intake is often enough to bring levels down within hours. Aim for steady sipping rather than gulping large amounts at once, since your kidneys can only process fluid at a certain rate.
Plain water works best, but if you’ve been on a low-carb diet or have been vomiting, you’re likely losing electrolytes along with water. When carbohydrate intake drops below about 50 grams a day, lower insulin levels cause your kidneys to flush sodium and water at an accelerated rate, dragging potassium, magnesium, and calcium along with it. Adding an electrolyte drink or broth can help you stay hydrated more effectively than water alone, especially if you’re feeling dizzy, crampy, or fatigued.
Eat Carbohydrates
Ketone production stops when your body has enough glucose available. The ketogenic diet works by keeping carbohydrates below about 50 grams per day (less than what’s in a single plain bagel), so eating above that threshold tells your liver to stop producing ketones. If your goal is to clear ketones, eating a normal meal with bread, rice, fruit, or pasta gives your body the glucose signal it needs.
You don’t need to eat a huge amount. A piece of toast with juice, a bowl of oatmeal, or a banana with crackers provides enough carbohydrates to shift your metabolism back toward glucose burning. For people with diabetes, this step needs to be paired with proper insulin management, since eating carbohydrates without adequate insulin won’t solve the problem and can push blood sugar even higher.
What to Know About Exercise
Exercise can seem like a logical way to “burn off” ketones, but it can actually make the situation worse. When you exercise with ketones already present, your body ramps up fat burning even further, which produces more ketones. The American Diabetes Association recommends avoiding vigorous activity if you test positive for ketones in your blood or urine. Light activity like walking is generally fine if you feel well, but hold off on anything intense until ketones have cleared.
How to Check Your Levels
Over-the-counter urine test strips are the easiest way to monitor ketones at home. You dip the strip in a urine sample (or pass it through your stream), wait the time specified on the package, and compare the color change to the chart included. Results fall into general ranges:
- Small: under 20 mg/dL
- Moderate: 30 to 40 mg/dL
- Large: above 80 mg/dL
Small levels typically respond well to extra fluids and a carbohydrate-containing meal. Moderate levels warrant closer attention and retesting within a few hours. Large levels, especially combined with high blood sugar in someone with diabetes, can signal a dangerous condition called diabetic ketoacidosis (DKA).
How Long Clearance Takes
For diet-related ketones, eating a normal amount of carbohydrates and drinking plenty of water can bring urine ketone levels back to zero within 12 to 24 hours for most people. Your body needs time to shift its metabolism, use up the ketones already circulating, and flush the remainder through your kidneys. If ketones are caused by illness, vomiting, or an inability to keep food down, clearance takes longer because the root cause is still active.
Retest every few hours after you start hydrating and eating. If levels aren’t dropping after several hours, or if they’re climbing, the underlying cause likely needs more than home measures to resolve.
When Ketones Become Dangerous
For most people following a keto diet or who skipped a few meals, trace ketones in urine are not an emergency. The situation is different for people with diabetes. High ketones combined with blood sugar at or above 300 mg/dL is a medical emergency. DKA can develop quickly and become life-threatening.
Call 911 or go to an emergency room if you have high ketones along with any of these signs: blood sugar that stays at 300 mg/dL or above, breath that smells fruity, vomiting that keeps you from holding down food or drinks, or difficulty breathing. Multiple symptoms appearing together make emergency care especially urgent. DKA requires IV fluids and insulin that can’t be replicated at home.
Addressing the Underlying Cause
Clearing ketones from your urine is straightforward in the short term, but they’ll come back if the trigger remains. If you’re intentionally following a ketogenic diet but want a clean urine test (for a physical, insurance screening, or personal reassurance), simply eating normally for a day or two beforehand will do it. If you’re pregnant, ketones can appear from nausea-related food aversion or going too long between meals. Eating smaller, more frequent meals with carbohydrates helps prevent them from returning.
For people with diabetes, recurring ketones point to an insulin management problem. This could mean a missed dose, an insulin pump malfunction, an infection raising your body’s insulin needs, or a dose that hasn’t kept pace with changing requirements. Tracking when ketones appear and what preceded them gives you useful information to bring to your care team.
Prolonged vomiting, diarrhea, heavy alcohol use, and eating disorders all cause ketones by depriving the body of glucose. In these cases, clearing ketones from urine requires treating the condition driving the fuel shortage, not just drinking water.