The defining aspect of the ketogenic diet, aka keto, is that it's low-carb in the extreme. Just how low-carb? If you're doing keto right, carbs should account for five to 10 percent of your daily macronutrient intake. The actual amount in grams varies based on your weight and fitness level, but it could be anywhere from 30 to 100 grams per day. To put that in perspective, there are 27 grams of carbs in just one average-sized banana.
If weight loss is your goal, eating fewer carbs can help — it's one of the most effective ways to lose weight and keep it off. But you don't have to go on the keto diet to do it: a general low-carb diet, rather than the extreme keto version, is another option. But what exactly is the difference?
Low-Carb vs. Keto: What's the Difference?
The biggest difference between keto and low-carb, according to dietitian Kristin Kirkpatrick, RD, of the Cleveland Clinic's Wellness Institute, "is that the main goal of keto is to induce ketosis." Ketosis is a metabolic state in which your body switches over from burning glucose and glycogen (the stored form of glucose), both of which are sourced from carbs, to burning fats. The process produces ketones, which are compounds made by your liver using fatty acids, hence the name "ketosis." It's hard to get to this state and especially hard to maintain it because of how low you have to keep your carb intake, but it can result in weight loss.
A regular low-carb diet, in comparison, may never reach the state of ketosis, Kirkpatrick said, and not only because you're eating more carbs than in a keto diet. Keto limits all the macronutrients: 5-to-10 percent of your diet is carbs, 15-to-20 percent is protein, and 60-to-75 percent is fat. A low-carb diet could actually have a similar level of carb restriction; Kirkpatrick said that the daily amount can vary between people. The Mayo Clinic defines a low-carb diet as 20 to 60 grams a day, which is within most people's keto percentages. What makes keto different is that it restricts protein as well. Protein is a source of amino acids, Kirkpatrick explained, which your liver can turn into glucose for fuel instead of using fat as it would in a true keto diet. You'll need to downsize on both protein and carbohydrates, then, to force your body into ketosis, and a low-carb diet only restricts carbs.
For comparison, the USDA's current Dietary Guidelines For Americans recommends a diet of 45-to-65 percent carbohydrates. If you just stick to the lower end of that spectrum, as Michele Fumagalli, RD, LDN, a registered dietitian with Northwestern Medicine, told POPSUGAR in a previous interview, the diet you end up with may be much lower-carb than you're used to — without going on keto or a specifically low-carb diet. Keeping carbs to a fourth of your plate might seem low-carb, she said, but that's actually fairly normal.
Pros and Cons of a Low-Carb Diet
A low-carb diet has a few benefits:
- You may lose weight on a low-carb diet. Studies have found that low-carb diets can help you lose weight, and you may also see results more quickly than you would on a low-calorie, low-fat diet.
- It's less restrictive and more sustainable than keto. Low-carb diets are less strict than keto, which many people find more sustainable in the long term. Unlike with keto, you only limit carbohydrates, which means you can still eat higher amounts of protein.
There are also some negative sides to a low-carb diet:
- You might experience constipation. A low-carb diet tends to restrict your fiber intake, which can lead to constipation.
- Your diet may become less well-rounded. You may not realize how many carbs are in fruits and vegetables until you try a low-carb diet. While trying to stay within your carb limits, you might find yourself skipping out on fruits, vegetables, and other nutritious foods that would otherwise be a part of your daily diet.
Pros and Cons of the Keto Diet
Keto is popular for a reason. Here are some pros to the keto diet:
- Keto has been used to manage epilepsy and type 2 diabetes. Keto isn't just about weight loss. This diet has been effective in managing conditions like epilepsy, due to the low-sugar, high-fat diet's effect on the brain, and type 2 diabetes, as it helps the body keep glucose levels low. Keto can also help with cholesterol issues.
- You may lose weight on keto. Keto is a popular choice for people looking to lose weight, and has been shown to help with weight loss and appetite reduction, though more long-term research is needed.
These are a few keto diet cons to know about:
- You might experience keto flu. When you switches your primary energy source from glucose (via carbs) to fat, keto flu can come as a side effect as your body tries to adjust. Keto flu can last a few days or a few weeks, and symptoms can include headaches, brain fog, fatigue, stomachaches, and nausea.
- Constipation is common. As with other low-carb diets, the low amount of fiber in the keto diet can make you constipated.
- Keto can be hard to sustain. Because it's so restrictive, many people have trouble sticking to the keto diet for long periods of time. Depending on how you transition away from keto, you may gain weight after going off the diet.
- Keto can be trigger for people recovering from eating disorders. If you have had an eating disorder in the past or have disordered eating tendencies, you may find keto's restrictiveness to be triggering.
- Keto can cause kidney stones. Studies show that kidney stones can be a side effect of keto, though potassium citrate supplements may lower the risk.
Low-Carb vs. Keto: Which is Better For Weight Loss?
Despite a lack of long-term studies on keto and weight loss, Kirkpatrick told POPSUGAR that if followed closely, both keto and low-carb diets can help with losing weight. What it really comes down to, she explained, is which is more sustainable for long-term weight maintenance. It's notoriously tricky to stay on track with keto, "because the keto diet has to be followed perfectly to stay in ketosis." Even falling off a little bit, Kirkpatrick said, can throw you out of that fat-burning state. Not to mention the sheer power of the carb cravings, which can be stronger on a more restrictive diet like keto.
"Many of my patients have found it easier to sustain low-carb than keto," Kirkpatrick said, "because it allows more flexibility in range of carbs, and it doesn't necessarily limit protein content of any kind." But if you have the motivation and work well under clear rules, she said that the keto diet might work for you. The bright side of keto's macronutrient restrictions is how clearly-defined they are; a low-carb diet doesn't offer the same guidance. Depending on your lifestyle and personality, the restrictiveness can be a help or a hindrance for weight loss.
"The best way to determine which diet is right for you is to look at other factors in your life," Kirkpatrick said. Think about your schedule, current diet, any chronic conditions, and other aspects of your lifestyle that might derail you. (If you have a partner or family that eats carbs, for example, it will likely be harder to stick to keto.) Whatever you choose, remember that fitness goals take time to achieve, including weight loss, so be prepared to commit to your diet for a few months before seeing results.