When you're following a new fitness program or diet plan, drinking enough water to stay hydrated and look and feel your best is a no-brainer. But you may need to drink even more water with lifestyle changes such as the low-carb, high-fat ketogenic diet.
"When you eat very few carbs, your liver releases glycogen, the storage form of glucose (sugar), and for every gram of glycogen that is released, two grams of water are released and excreted in the urine," Franziska Spritzler, RD, a certified diabetes educator in Huntington Beach, CA, told POPSUGAR. "During this time, you should drink at least 2.5 liters of water or fluid per day to replace the amount lost in urine. Once you become keto-adapted, you should still consume a minimum of two liters of water daily in order to prevent dehydration and promote optimal metabolic health."
Shauna Sacco, MS, RDN, a certified personal trainer and registered dietitian in Houston, added that beyond that minimum recommendation, additional water needs can vary from person to person.
"Many people rely on their bodyweight to determine how much water they need," she said. To do the same, calculate 75 percent of your weight, then aim to drink that many ounces of water per day. (For example, if you weigh 120 pounds, you should drink at least 90 ounces of water.) "The keto diet eliminates many other sources of water, like fruits and some vegetables, because of their carbohydrate content," Sacco explained. "Eliminating fruits and vegetables can also drastically reduce your fiber intake, which can lead to constipation, and drinking enough water can help to ease that."
So, now that you know how much water you need, how can you make sure you're getting enough?
"Follow your body's thirst cues by keeping a water bottle with you that you can sip throughout the day," Sacco said. You should also lower your caffeine intake and exercise regularly to help move digestion along. "All of this will make a difference in the effectiveness of the diet and how you feel," she said.