Compared to the low-fat craze in the ’90s, the ketogenic diet seems to go against all diet logic. Because instead of cutting out fat, you eat large amounts of it for every meal.
Research shows that the ketogenic diet can be effective at helping to fight diseases related to obesity. That said, the keto diet is not for everyone. Here’s what you need to know.
The ketogenic diet — keto for short — is a restrictive diet where you replace carbs with fatty foods.
For example, carb-rich foods like bread, rice, and potatoes are usually eliminated, or severely reduced, because they’ll easily tip you over the limit of 20-50 grams of carbs per day. Meanwhile, low-carb fatty foods, protein, and non-starchy veggies are prioritized. 
There’s some variation of the keto diet, so there is some wiggle room for catering it to your particular lifestyle and eating preferences. Here are six different types of the ketogenic diet:
A typical ketogenic diet consists of 75% fat, 20% protein, and 5% carbs. On keto, common foods that you’re allowed to eat include:
Common foods you’re recommended to avoid while on keto are:
When you follow the ketogenic diet, your body stops relying on carbs as the main source of energy. This sends your body into a metabolic state called ketosis. 
Ketosis is when your metabolism burns fat for energy instead of carbohydrates, and produces molecules called ketones in the process.
Normally when you eat sugar and carbohydrates, your body turns them into glucose, aka blood sugar. Then, your liver releases insulin, which helps your cells absorb that glucose for energy.
But when you limit your sugar and carb intake, there’s nothing for your body to turn into glucose. As a result, blood sugar levels remain low, and your body generates ketones, instead.
Ketones are acidic, so too many in your body are potentially harmful. However, it’s this ketone production that makes the keto diet so helpful for people with certain neurological diseases.
That’s because of how the brain processes ketones differently compared to glucose. The key difference is how much energy ketones provide the brain in the form of ATP. ATP is basically your brain’s version of food, and ketones offer more ATP per molecule compared to glucose.
For example, 100 grams of glucose generates 8.7 kilograms of ATP whereas the same amount of a ketone, called acetoacetate, generates 9.4 kilograms of ATP. Ketones are a more efficient fuel source for the brain. 
This may help partly explain why some research has found a helpful link between keto diets and certain neurological diseases like epilepsy and Alzheimer’s. Other evidence suggests that the keto diet helps with protein build up in the brain that reduces its capacity as well as helps with inflammation in brain cells. There are many possible explanations that continue to be studied. 
The ketogenic diet gets a lot of attention for its purported weight-loss benefits, but it can also be beneficial for those suffering from neurological disorders like epilepsy and insulin disorders like type 2 diabetes.
Moreover, some research indicates that the keto diet can also help with PCOS, fertility, and more.

Here’s what researchers know so far about the keto diet’s many health benefits:
Can regulate type 2 diabetes
The keto diet has been shown to help people with type 2 diabetes because of how it maintains low blood sugar levels, and subsequently, can promote better insulin control.
May help you lose weight 
The keto diet has been shown to help with weight loss — specifically fat reduction — because it can suppress appetite and kick start fat-burning through ketosis. 
Can help manage epilepsy 
When following the keto diet, weight loss can vary from person to person, says Jeff Volek, a registered dietitian and professor at Ohio State University.
“When people with excess weight start a ketogenic diet, they typically lose about six to eight pounds the first week, then about 1 to 2 pounds per week thereafter,” Volek says. 
However, some people who go on keto reportedly suffer from some initial side effects including:
The initial weight loss is partly due to losing water weight because you tend to retain less water on a low-carb diet. And some studies suggest that you may not continue to lose weight on keto long-term. Some call this the “keto plateau” which is when you stop losing weight altogether.
The ketogenic diet isn’t necessarily for everyone. Take kids, for example. Nutritionists told Insider that putting children or teens on the keto diet — or any restrictive diet — can lead to nutritional deficiencies and eating disorders. Keto can be used to treat seizures in children, but this is an exception to the rule.
Here are some other downsides of the keto diet and who should not try it:
The ketogenic diet, famous for its touted weight loss benefits, is essentially a low-carb diet. There are many variations of this diet suited to different needs and goals. 
However, the keto diet doesn’t just help with weight loss. Evidence indicates that it has clinical and therapeutic benefits in treating type 2 diabetes and epilepsy. 
The keto diet is not for everyone and you should speak with a certified nutritionist before starting it, especially if you have a medical condition that the diet may affect.

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