Eating keto style is about more than just gorging on bacon and butter. Here are expert answers to your most pressing keto diet questions.
Every product is independently selected by our editors. If you buy something through our links, we may earn an affiliate commission.
Is the keto diet safe?
To put it simply, yes and no. The ketogenic diet has been around for 90 years. It was first developed to treat patients with epilepsy, who responded well to the way it mimics a fasting state, while still allowing patients to eat and obtain nutrients. The keto diet is highly restrictive, though, cutting out grains and certain fruits and veggies in addition to sugar—which as a short-term diet solution may have some benefits, but long term may be risky.
“The ketogenic diet is not a healthy, nutritionally complete diet,” says Diana Lehner-Gulotta, RDN, a ketogenic and neurology dietitian at University of Virginia Health System. “You are completely cutting out large groups of food and eating excessive amounts of fat, which can lead to lipid abnormalities. We also don’t know about the long-term effects of eating such a high-fat diet.” If you’re thinking about following the keto diet for a weight-loss kick start, talk with your doctor first. Here are 13 things doctors want you to know about the keto diet.
What’s the difference between net carbs and total carbs?
Net carbs are the number of carb grams that remain after dietary fiber and sugar alcohols are subtracted from the total carbohydrates of a meal. Why don’t many keto dieters count fiber in their total carb allotment for the day? The fiber found in many keto-compliant foods, such as broccoli, avocados, and berries, is indigestible once eaten. So, while these foods technically still contain “carbs,” the body can’t use them for energy.
“There’s no right approach between counting ‘net’ and ‘total’ carbohydrates,” says Paul Salter, founder of the Weight Maintenance Channel on YouTube and nutrition editor for Bodybuilding.com. “Using net carbs is a tool to ensure you’re seeking high-fiber carbohydrates, which is essential when following a ketogenic diet.”
What are your nutrient goals—and how will you track them?
The keto diet is an ultra-low-carb diet. This means you’ll be eating significantly fewer carbohydrates than the average person, even fewer than a person following a classic low-carb diet. Exactly how many carbs you should aim to eat depends on your specific goals, as well as your age, gender, and level of activity, says Salter. Ketogenic diets tend to limit carbohydrate intake to just 20 to 30 net grams per day. On a standard ketogenic diet, fats typically make up 70 to 80 percent of total daily calories, protein about 15 to 20 percent, and carbs just around 5 percent.
Keep track of these important nutrients with nutrition calculators, tracking programs, or smartphone apps like MyFitnessPal and MyPlate. Find out what it’s really like to follow the keto diet.
How much weight will you lose on the keto diet?
Weight loss is very common with the keto diet, however, the first few pounds you drop will be “water weight”—water that your body would normally store when you eat carbs. What’s happening is just the opposite of what happens to marathon runners when they carb-load. “Carbo-loading, which athletes do, fills muscles with as much glycogen, a storage form of sugar, as possible, which holds more water,” says Melina Jampolis, MD, author of The Doctor on Demand Diet.
During keto, as you reduce carb intake your body dumps its glycogen stores in favor of burning fat. You’ll see the number on the scale go down, which is exciting, but at this point, you’re just dropping water weight, not fat. “Oftentimes, people are discouraged that their rate of weight loss slows down after the first month, but this is healthy,” Lehner-Gulotta says. “In addition to weight loss, many people feel like they have more energy and mental clarity on this diet.”
What else changes? Sugar cravings become non-existent after the first few months, Lehner-Gulotta reports. Her patients tell her that they feel more satisfied after meals, and they’re not hungry all the time. Read more about how the keto diet helped one woman lose 15 pounds in six weeks.
Will you feel hungry on the keto diet?
Hunger is suppressed on the keto diet. Fat is satiating, so you may find yourself feeling not very hungry some days when you’re on the keto diet. That’s okay. In fact, it’s why many keto dieters eventually begin practicing intermittent fasting (IMF), says Salter. IMF allows you a shorter window of eating, such as only eight to 12 hours each day, then you fast during the remaining time.
Note that fasting is not without medical concerns. “The theory with fasting is that it will help decrease your appetite and cravings over time because it will teach your body to go longer without food,” Lehner-Gulotta says. But it’s not for everyone. In some people “it causes irritability, further nutritional deficiencies, and often leads to loss of lean muscle mass instead of fat.” Talk to your doctor before trying it.
Will you get the dreaded “keto flu”?
Carbohydrates are your body’s preferred source of fuel, and without them your body turns to a stored source of energy—fat. When your body is adjusting to burning fat (a process called ketosis), you may experience unusual symptoms, such as irritability, brain fog, fatigue, mood swings, or nausea, Lehner-Gulotta says. This is sometimes referred to as the “keto flu.”
Not every person eating keto will experience this, but some will. “It’s important to stay hydrated and push through because if you give in and eat carbs, you’re right back where you started,” Lehner-Gulotta says. The good news is that the symptoms come and go and usually subside altogether within three to five days.
Does the keto diet have benefits beyond weight loss?
Research suggests the keto diet may deliver health benefits beyond weight loss, such as improved blood sugar levels, insulin sensitivity, and cholesterol numbers, says Grace Derocha, RD, certified diabetes educator, and certified health coach at Blue Cross Blue Shield of Michigan.
Whether it’s the keto diet itself or the accompanying weight loss that is actually responsible for improvements in some health markers, Derocha says, is unclear. “There needs to be more research done regarding the keto diet, its long-term effects on the body, and the impact of the keto diet once someone decides to incorporate a more sustainable meal plan.”