The keto diet has exploded in popularity, and it's no surprise why — going keto has helped people lose weight, in some cases more than 150 pounds. But the diet, which is high in fat, is also controversial, as dietitians worry about the implications of cutting out an entire food group (grains and carbs) and eating an abundance of saturated fat.
But if you're curious about embarking on the keto diet, here's everything you need to know before getting started. Although it may help you lose weight, it's best to speak with your doctor before making any major dietary or lifestyle changes.
What Is the Keto Diet?
The ketogenic diet, or keto for short, is a high-fat, moderate-protein, and super-low-carb diet. By eating so few carbs, your body enters a state of ketosis, where your body produces ketones for energy instead of carbs. Ketones are produced by the liver using fatty acids from your food or body fat, so basically your liver burns fat to make ketones, which are used as fuel. As your body continues to use fat for energy, you will lose weight.
What Can I Eat?
Most people associate the keto diet with bacon, butter, and cheese, and while these are all keto-approved foods, the diet doesn't have to be a saturated-fat fest. "A ketogenic diet does not have to be heavy on butter and meat!" Catherine Metzgar, PhD, RD, and a member of the clinical team at Virta Health, told POPSUGAR. "In fact, many of my patients are vegetarians and do very well." The macronutrient breakdown should be about 80 percent fat, 15 percent protein, and five percent carbs.
Since the diet is rich in fat, a lot of plant-based fats are consumed: nuts, avocados, olives, and oils such as extra virgin olive oil and coconut oil. But if you want to eat animal products, pretty much every kind of meat, seafood, eggs, and cheese are on the table. For a more exhaustive list of what you can eat, check out our keto foods list.
What Are the Side Effects of Starting the Diet?
One of the biggest side effects people talk about when starting keto is the "keto flu." Basically, when your body transitions from burning carbs for fuel to burning fat, your kidneys also switch from retaining salt to excreting it in your urine, Dr. Metzgar explained. "This dumping of salt into the urine is why people can feel unwell (i.e. headaches, fatigue), and it is solved by increasing sodium intake," she said.
Some people may also get magnesium cramps, which she suggests can be alleviated by taking a magnesium supplement. "Getting plenty of fluids will also aid in managing symptoms," she added. Also, as the excess ketones exit your body through your urine and your breath, you may notice bad breath, known as keto breath. It might also make your urine smell weird.
What Else Should I Know Before Starting?
If you've learned about what the keto diet means, stocked up on all the keto-approved foods, and still want to embark on the diet, Dr. Metzgar says it's important to evaluate why you want to go keto.
"Before you give keto a try for the first time, I strongly recommend that people reflect on what their goals are and what they can sustain, she said. "If you are relatively healthy with a primary goal to lose weight, other dietary approaches that focus on calorie reduction, such as Paleo, may feel less restrictive."
She added that most people stop following the keto diet after six months or less and regain all the weight back that they lost after returning to their old habits. "To achieve the maximum benefits from a ketogenic diet, this should truly be a lifestyle change," she said. If you're not losing weight right away, don't fret; on average, she said, it takes about two weeks for the body to adapt to burning fat for fuel over carbs. Make sure you stick with it for a couple weeks to ensure your body is actually entering ketosis.
And before embarking on any diet or lifestyle change, it's a good idea to get the go-ahead from your doctor, especially with something as drastic as the keto diet, especially if you are diabetic or taking blood pressure medication.