Many different versions of low-carb diets have come and gone over the past several decades, but one carb-restrictive diet that’s been around for generations and is garnering significant attention today is the ketogenic diet, also known as the keto diet.
This way of eating is often considered the most effective diet to lose weight quickly. The keto diet is also said to be the key to a long, healthy life.
But what is it really all about? In this article, you’ll get the keto diet explained:
What is the Ketogenic Diet?
The keto diet is very high-fat and low-carb way of eating. The goal is to reach a state called “ketosis,” a metabolic state modeled after fasting.
Here’s what the macronutrient distribution looks like on a ketogenic diet:
55 to 60% fat30 to 35% protein5 to 10% carbohydrates
An average adult requires about 2000 calories per day. On the keto diet, you are only permitted 20 to 50 g of carbohydrates.(1) However, according to the Dietary Guidelines for Americans, a balanced diet should consist of at least 45% carbohydrates.
Meat, fish, eggs, cheese, nuts, seeds, low-starch vegetables, avocados and (preferably) vegetable fats.
The term “ketogenic diet” was coined by American physician Russel M. Wilder. In 1921, Dr. Wilder introduced a keto diet to treat children with epilepsy at the Mayo Clinic in Minnesota. This diet led to a reduction in epileptic seizures. Since then, it has been used as a nutritional therapy to treat epilepsy in children.(2) It can also be used to treat rare metabolic diseases, but always under medical supervision.(3)
What is Ketosis and How do You Get There?
Ketosis is a metabolic state modeled after fasting. So what does that mean in everyday life? By greatly reducing carbohydrate intake in favor of fat, the body enters a state of ketosis. Ketone bodies are produced when fats are broken down in the liver (this process is called beta-oxidation). These can be used by organs (e.g. brain) to supply energy when there is not enough glucose available. This leads to the state of ketosis.
It is not yet clear how ketosis reduces epileptic seizures. Experts suggest that ketones protect nerve cells, improve the brain’s energy supply, and reduce inflammation.(4)
Temporary side effects of the keto diet
Some people will temporarily experience keto diet side effects while they transition into ketosis, but those symptoms typically subside within 1-2 weeks.
Potential side effects (sometimes called the “keto flu”):
headacheslow energycravingsweakness brain fog
Ketogenic Diet: A Miracle Weight Loss Cure?
It’s true that you’ll lose weight fast on a ketogenic diet – faster than with a high-carb, low-fat diet. This has been observed in studies carried out over a six month period.(5) Why, you may ask? At the beginning of a low carb diet you lose a lot of water. However, in the longer term, it seems to make little difference. Research showed that weight loss results were ultimately the same. The crucial factor for weight loss is that you are in a calorie deficit. If you want to lose weight, you need to burn more calories than you consume.
A ketogenic diet also seems to have an effect on the hormone balance in your body. One study found that the hunger hormone ghrelin was altered or even suppressed in patients who lost weight on the keto diet.(6) The strict low-carb diet also appears to reduce appetite.(7)
The Ketogenic Diet and Your Gut Flora
Your gut needs fiber to do its job. Healthy adults should consume between 25 and 38 g per day.(8) The two different kinds of fiber – soluble and insoluble – are both important for the intestinal flora. They are mainly found in:
FruitVegetablesLegumesWhole grain products
The problem is that all these foods are forbidden in a ketogenic diet, because they are high in carbohydrates. As you can imagine, this can cause some intestinal problems. A study conducted over ten years examined the effects of the keto diet on 48 children.(9) Results showed that 65% of the kids struggled with severe constipation. This is why it’s especially important to make sure you’re drinking enough fluids if you follow a ketogenic diet.
Do you lose muscle mass on the keto diet?
Some athletes want to try a ketogenic diet, but worry that they will lose muscle mass. This is understandable, considering the importance of consuming a combination of carbohydrates and protein after workouts to build muscle and regenerate.
However, studies on the subject show mixed results. One study showed an increase in muscle mass after ten weeks of the ketogenic diet followed by two weeks of reintroducing of carbohydrates among men who did regular weight training.(10) Other studies(11,12,13) show that muscle mass was maintained but did not increase. Remember to consume plenty of protein and do regular strength workouts.
Do you do high intensity training? A ketogenic diet isn’t the right fit for you. A low-carb diet can have a negative impact on performance.(14)
Find out easily with our protein requirement calculator:
If you want to lose weight fast, the ketogenic diet seems ideal; you’ll see results quickly.
This diet can also work well for athletes, depending on what your goal is.
However, think about whether you can follow the ketogenic diet plan long term and integrate it into your everyday life. In a balanced diet, there is room for all foods in moderation. Variety and balance prevent cravings and the infamous yo-yo effect. This also ensures you’ll have enough energy reserves for tough workouts and training. Plus, high-fiber foods like carbohydrates, such as fruits, vegetables, and legumes keep your gut healthy and your digestion regular.
The keto diet has shown good results for patients with epilepsy and some rare metabolic diseases. However, don’t try to treat your condition without professional supervision (doctors, dieticians). Research continues on how exactly the keto diet works in the body and how it can be used to treat various conditions.