Frequently Asked Questions
Is the Keto Diet Safe to Follow?
Even though following an extremely high fat diet can feel like a radical way to eat, “the research looking at ketosis via diet has not shown any real negative consequences when done in the short term,” says Scott Keatley, RDN, of Keatley Medical Nutrition Therapy in New York City. (Ketosis is the natural metabolic state that makes keto lead to weight loss.)
But there have been few long-term studies, adds Kendra Whitmire, a nutritionist and dietitian in Laguna Beach, California, who practices functional and therapeutic nutrition. It’s difficult to definitively say that it’s safe, and it also largely depends on the types of foods you’re eating on a keto diet. (For instance, olive oil is a healthier choice than butter; salmon is healthier than bacon.) That said, following the keto diet properly, and particularly with help from a medical professional, should reduce negative health effects, says Whitmire.
Is Ketosis Bad?
Typically, your body breaks down carbohydrates as its preferred fuel source. Ketosis is when your body has switched into a fat-burning state and breaks down fat into ketone bodies that are used as energy. Beyond the keto flu, “many studies have shown that entering ketosis via diet does not have any real negative consequence in the short term,” says Keatley.
But long-term studies are needed to truly assess the impact, he adds. Bottom line: Putting your body into ketosis for a limited time is likely not harmful.
How Many Carbs Do You Actually Eat on a Keto Diet?
A keto diet is generally made up of 70 to 75 percent fat, 20 to 25 percent protein, and 5 to 10 percent carbohydrates, says Jill Keene, a registered dietitian nutritionist in private practice in White Plains, New York. The exact number of grams (g) of carbohydrates will be different for everyone, but is generally around 20 to 50 g per day. Many people on a keto diet count “net carbs,” which is total carbs minus fiber. Fiber isn’t “counted” in the carbohydrate total, because it’s not digested. Either way, this number of carbs is very low and requires careful planning. Eating a little fruit, starchy vegetables, sugary foods, or whole grains can easily kick you out of ketosis.
Can You Drink Alcohol on the Keto Diet?
Yes. “Even though there are [often] carbs in alcohol, you can still drink it in limited amounts,” says Keatley. Realize that on days when you do choose to consume alcohol, depending on what you choose, you may have to adjust your carbs from other sources. This may mean making tough decisions, like having a drink but skipping a small amount of fruit or Greek yogurt.
In general, the simpler the better: Spirits are the best choice (avoid mixers that have calories), followed by wine. Your best bet is to stick with a half drink, says Keatley. Because of their lower alcohol percentage and other ingredients, beer and wine “can eat up a lot of your carbs, and they don’t give back in terms of vitamins and minerals. It’s a waste of your carbs,” he says.
How Much Weight Can You Lose on the Keto Diet?
There’s no doubt that a ketogenic diet may help spur weight loss — and anecdotal reports of drastic transformations are easy to find. “I have clients who have lost a significant amount of weight on a keto diet, but they were obese when starting and had quite a bit of fat to lose. These individuals have fairly drastic body transformations,” says Keatley.
But long-term studies show that there’s not much of a difference in weight loss between keto and other diets. One meta-analysis published in October 2013 in the BMJ compared adults on a ketogenic diet (eating less than 50 g of carbs) with those on a conventional low-fat diet. After at least a year, those on the keto diet lost an additional two pounds compared with the group who slashed fat. The bottom line is that diets, including keto, may help you lose the same amount of weight in the long run. With that news, know that there may be a better option out there for you, says Keatley.
What Fruits Can I Eat on the Ketogenic Diet?
Fruit is generally not a mainstay of the keto diet. With so much natural sugar, fruit generally has too many carbs to be included. But you can have small amounts of lower-carb fruits, like berries, says Whitmire. And if you’re really getting technical, avocado and coconut, two higher-fat foods, are, in fact, fruits.
Can I Eat Snacks Like Popcorn, Oatmeal, and Yogurt on Keto?
Unfortunately, high-carb foods like popcorn or oatmeal probably won’t fit in the keto diet. One cup of air-popped popcorn contains 5 g of net carbs, which may be ¼ of your carb allotment for the entire day. It’s also worth mentioning that one cup of popcorn is not a large serving; it contains just 30 calories and no fat, so it won’t be filling. Oatmeal likely doesn’t fit, either. About ¼ cup of plain dried oats (about ½ cup cooked) has 12 grams of net carbohydrates for 77 calories and just one gram of fat.
