How Many Carbs Should I Eat to Prevent Ketosis?

When you're on a low-carb diet, your body kicks into action, breaking down fats into ketone bodies to use for energy. This increase in ketones — called ketosis — is a normal adaptation to cutting carbs. In fact, the switch to ketosis is why low-carb diets work. Even though you could eat enough carbs to prevent ketosis, it's important to clarify why you want to avoid it. There's nothing unhealthy about ketosis, so you may just need to correct any misinformation to make the best decision for your weight-loss goals.

Ketosis is often confused with ketoacidosis, which is unfortunate -— ketosis is normal, while ketoacidosis is a dangerous condition related to type 1 diabetes. Most people on a low-carb diet tolerate ketosis without any problems. Then after the pounds are dropped, carb intake is gradually increased so you're out of ketosis by the time you reach the maintenance phase. If you decide to stay in an induction phase longer than the low-carb plan recommends, consult your doctor to be safe.

People with type 1 diabetes are at risk for developing ketoacidosis from lack of insulin. Due to the complex metabolism of diabetes, they end up with high levels of blood glucose and ketones, which upsets the body's normal acid-base balance. When that happens, ketosis becomes ketoacidosis, causing symptoms like thirst, frequent urination, dry mouth, nausea, belly pain, rapid breathing and fruity-smelling breath. If you have symptoms, contact your doctor immediately -- diabetic ketoacidosis is a medical emergency.

You may be wary about ketosis because you've heard about "ketosis flu." It's not really flu, but in the first few days or weeks of a low-carb diet, some people experience headaches, dizziness, fatigue, constipation or weakness. Don't worry — it's only temporary as the body adjusts to reducing carbs. Because ketosis flu is caused by loss of water and salt, you'll prevent the problem by drinking eight glasses of water and by having a cup of broth every day, suggests Atkins.

By definition, a ketogenic diet includes fewer than 50 grams of carbohydrates daily, according to a review published in the European Journal of Clinical Nutrition in August 2013. Simply put, you should be able to prevent ketosis if you eat more than 50 grams of carbs daily.

Just remember that 50 grams is a general guideline more than a hard-and-fast rule. If you engage in sports or intense activities that burn lots of calories, your body may begin using ketones for energy if you drop below 80 or 100 grams of daily carb intake.

If you're determined to avoid ketosis, you'll need to experiment to find the point at which your body begins to burn ketones rather than glucose. You can develop a plan to eat a set number of carbs for at least three days, then adjust carbs up or down depending on whether you detect high ketone levels.

Excess ketones come out through your breath and urine, so signs that you're in ketosis include fruity-smelling breath and urine that has a fruity odor or smells like nail polish remover. You can also buy urine test strips at the local pharmacy to get a precise read on ketones. Another good alternative is to consult a registered dietitian, who is trained to develop a diet that works for your metabolism and activity level.

While there isn't one standard definition of a low-carb diet, consuming fewer than 130 grams of carbs daily puts you on a low-carb eating plan. If you get 50 to 130 grams of carbs daily, you'll avoid ketosis, but you won't get the results expected from a low-carb diet. By comparison, the first phase of most low-carb plans calls for 20 grams of net carbs daily, which are tallied by subtracting fiber from total carbs.

You'll need to be more diligent about restricting calories if you want to lose weight while avoiding ketosis. On the upside, keeping carbs in the low range should still help you drop pounds, according to a study published in the Journal of Nutrition in January 2015. Researchers used two groups of subjects -- people who were overweight and overweight women with polycystic ovarian syndrome. After 16 weeks, subjects who lowered carb intake to 41 percent of daily calories lost 4 percent more body fat compared to the others, who followed a low-fat diet. If you consume 1,500 calories daily, that 41 percent equals 153 grams of carbs daily, which is above the low-carb range.

You may not realize how quickly the carbs add up when you follow a diet that allows enough carbs to avoid ketosis. For example, consider the carbs in a cup of plain oatmeal at breakfast -- forget the fruit, milk or sweeteners -- and two slices of whole-wheat bread on a sandwich at lunch. Both have the same amount of carbs -- 28 grams of total carbs and 4 grams of fiber, for 24 grams of net carbs each, or a total of 48 grams of net carbs. In just two meals you would meet your daily carbs if your goal was 50 grams daily.

The best way to limit carbs at the start of a diet is to stick with foods that have zero carbs or a trace amount. This list includes meats, fish, poultry, eggs and oils. Most types of cheese have very few carbs, except for processed cheese products and soft cheese. You can choose from most vegetables, but keep starchy ones, such as potatoes, beans, peas, corn and winter squash, off the menu. For fruits, go with berries, which have fewer carbs than other options. For example, 1/2 cup of fresh blackberries has 3 grams of net carbs, compared to 8 grams in half of an apple.