“If you don’t get enough fiber, you don’t get all the benefits of nutritional ketosis,” she says. According to Whittel, consuming fiber while on keto can "speed up your metabolism, balance your hormones, and keep you feeling full." The key is to get your fiber (the FDA recommends 25 grams a day) from non-starchy vegetables, nuts, seeds, and berries instead of traditional high-fiber foods like grains, beans, and legumes.
Hydration is even more crucial when you're on a ketogenic diet, explains Whittel, because your body is shedding that water that's attached to stored glycogen in your muscles. While drinking H20 is important so is incorporating hydrating foods. “I eat a ton of cucumbers, celery, and other hydrating greens,” she says. Drinking bone broth, adding chia seeds to smoothies and salads, and cooking with unsweetened coconut and coconut oil can also add structured water (which is more dense than regular tap water) to your diet and help keep you hydrated, Whittel explains.
The body’s transition from burning carbohydrates to fat (and its by-product, ketones) for fuel can sometimes result in the “keto flu,” a collection of symptoms that includes dizziness, lack of energy, headaches, and brain fog. That’s because at the beginning, your body will burn through stored glucose (glycogen), releasing water, sodium, and other electrolytes. This will cause your insulin levels to drop, and make your kidneys shed even more sodium and water. “Learning how much sodium, potassium, and magnesium I needed was my big aha moment,” says Whittel, who adds powdered electrolytes and Himalayan salt to her water before exercise.
“When I was going through a very stressful period, at first I couldn’t figure out why I had to focus more on my diet than before. It turns out that stress can take you out of nutritional ketosis,” says Whittel. “When you’re in fight or flight mode, your body doesn’t produce the same amount of ketones and will start grabbing glucose from the body,” she adds. On a physical level, coming out of ketosis may make you feel fatigued and foggy with carb cravings. According to Stephen Anton, Ph.D., a professor and chief of clinical research at the University of Florida’s Institute on Aging in Gainesville, constant high cortisol leads to muscle loss, and since muscle burns more fuel, you end up with reduced metabolic power.
“People on a keto diet oftentimes eat high protein, but they might actually not be getting enough fat,” says Whittel. A keto diet isn’t high in protein, but calls for only a moderate amount, or 20 to 25 percent of calories from protein, compared to 65 to 75 percent from fat. “When we over consume protein, that protein will turn into glucose and offset nutritional ketosis,” Whittel says.