Keto Side Effects

keto side effects


The tips for a low carb diet change between studies. According to research, low carb is generally classified as less than 30 percent of calories from carbohydrates. Most low carb diets include from 50 to 150 g of carbohydrates each day, a high amount of protein and also a fat intake that is moderate or high. However, for some athletes, “low carb” can include more than 200 grams of carbohydrates every day.

In comparison, a good ketogenic diet is more strict, it usually allows only 30 to 50 grams of carbohydrates per day, along with very high fat intake. This exceptionally low carbohydrate intake makes it possible to reach ketosis, a process where your body fat along with ketones becomes the main energy source, not only for your body but also for the brain.

Short-Term Side Effects

Approximately three or four days after starting the ketogenic diet, flu-like symptoms begin to appear, such as headache, tiredness, nausea, difficulty thinking or irritability. These symptoms usually disappear on their own after a week and are caused by dehydration and lack of salt.

Starting a low carb diet if you eat low fat will surely go hungry and this is not what you are looking for. Eat enough so that you feel satiated and energized. Ideally, add butter to what you consume.

This diet should be carried out with specialist supervision and not for a long time, since the contribution of vitamins, minerals, and fiber, fruits and vegetables is limited, which can cause periods of constipation, cramping, halitosis or asthenia.

To comply with this diet many healthy foods must be suppressed, which makes it difficult for the body to be given the necessary nutrients.

This diet is not recommended for people suffering from cardiovascular diseases, autoimmune diseases, osteoporosis, and certain deficiencies that should consult a specialist.

Alteration in Blood Composition

To maintain ketosis and avoid entering dangerous ketoacidosis, those who follow the keto diet should reduce, rather than increase, protein intake. The mistaken belief that keto is a protein-rich diet is the biggest and most dangerous myth that exists.

When protein levels increase, the breakdown of amino acids in it can also cause an increase in ketones. While that is very good in a common regimen, in someone who does this diet, who already has elevated ketone levels in his bloodstream, it can lead to ketoacidosis. If protein intake increases too much, it is converted to glucose, which causes a blood sugar spike and an antiestrogenic effect.

Long-Term Effects

Generally, a low-carb diet is beneficial for some. But it can be harmful to athletes and people looking for optimal sports performance.

Scientists at the Australian Sports Institute investigated the effect of a ketogenic (low carb) diet on elite athletes for 3 weeks.

The scientists took this group of athletes and performed a series of high-intensity workouts. A few days the athletes were fed a high carb diet and other days they consumed a low carb diet.

The two groups managed to increase their maximum VO2, but when consuming a low carb diet the body needed to consume more oxygen to maintain the same performance. In addition, the group that consumed a high carb diet managed to improve their walking time of 10 km and the low carbohydrate group failed to improve their times. The scientists conclude that adapting the body to this low carb diet denies the benefits obtained from training due to reduced athletic performance.

The Loughboroug University School of Sports Science conducted an analysis of several studies on the relationship between high-carb diets and athletes. This analysis found that a diet high in carbohydrates:

  • Help to recover more quickly to the liver and glycogen muscles.
  • Improves resistance capacity.
  • Prevents performance decline.
  • When consumed immediately after exercise, it helps speed up the glycogen resynthesis rate. This is essential for athletes competing on successive days.
  • Increase glycogen stores in the liver and muscles before doing sports helps delay fatigue.
  • When consumed during exercise, normally ingested as carbohydrate-electrolyte solutions, it usually results in better performance.

Side Effects in Adults

Through a low carb or ketogenic diet, the body starts to use fat differently, as some kind of fuel, this process is often called the adaptation. The drastic reduction of carbohydrates causes an increase in ketones, they are produced from fatty acids that exist in the liver. Ketones can offer energy in the absence of carbohydrates, during a prolonged fast, during long periods of exercise or for people who deal with uncontrolled type 1 diabetes.

The brain can also be partially fed by ketones. The remaining energy is offered by gluconeogenesis, a process where the body breaks down proteins and fats, converting them into carbohydrates (sugar). Ketones and ketogenic diets can have valuable properties and benefits for people. They are even used to reduce the effects of neurological diseases, diabetes or even cancer, as well as the risk factors for respiratory and heart disease.

The adaptation of fat in a diet can be quite powerful. A recent study of athletes revealed the fact that those on a ketogenic diet burned two times more fat in an exercise session that lasted for three hours. However, although both Kept and low carb diets allow you to enjoy the great benefits, the debate about the impact of these diets on exercise performance seems to be never-ending.

Dangers of Going Keto:

The “keto flu”

Ketogenic flu is a symptom experienced by some people when they start the ketogenic diet.

These symptoms, which may resemble flu, are caused by the body having to adapt to a new low-carbohydrate diet.

Reducing your carbohydrate consumption forces the body to burn ketone bodies instead of glucose.

Ketones are byproducts of fat breakdown and become the most important energy source when following a ketogenic diet.

Normally, fat is reserved as a secondary energy source for use when you have no glucose.

This change from burning fat to having energy is called ketosis. It occurs during specific circumstances, including fasting.

However, ketosis can also be achieved by adopting a very low carbohydrate diet.

In a ketogenic diet, carbohydrates are reduced to less than 50 grams per day. This way the body will have less glucose available to turn into energy.

This drastic reduction can be a shock to the body and cause similar withdrawal symptoms (yes, sugar is addictive).


It’s true, the Keto diet can help some people lose a lot of weight. But sometimes that weight loss comes at a price and when it comes to the ketogenic diet, high in fat, moderate in protein and low in carbohydrates, sometimes the price is ketogenic diarrhea.

That extra fat that the body does not use comes out in your stool and makes them more liquid than normal. (Let it be clear: Boules does not defend or encourage the ketogenic diet because of its high-fat content. “We have no idea what effects such a high-fat diet has for the long term health,” he says).

Another culprit of Keto diarrhea: using non-nutritive sweeteners (such as aspartame or Splenda) or sugar alcohols (such as sorbitol or xylitol) to replace the real sugar in Keto could also cause digestive problems. “Sorbitol in particular is sadly famous for causing GI discomfort,” he says, such as cramps or swelling, as well as diarrhea.

Reduced athletic performance

The research was conducted on the use of fats as fuel in athletic functionality. During exercise, fat supplies energy when the intensities are lower and carbohydrates provide more energy when the intensities are higher. Lately, researchers wanted to determine if a low carb diet could alter this effect. The research proved that athletes burned fat at up to 70 percent of maximum intensity, against just 55 percent in high-carb athletes. In fact, the athletes that were on a keto diet in this study burned the largest amount of fat ever recorded in a study.

Weight regain

Norwegian study claims that if after a while of doing it you decide to return to a non-ketogenic diet, you will feel of hunger again. Many people stop eating fruits and whole grains on a low carb diet but they are full of satiating fibers and have impact on a reduction in the heart disease rates, as well as diabetes and many other diseases.

Decreased metabolism

Studies have found that diets can help prevent fatigue during prolonged exercise. They can also improve your health, without making you compromise exercise performance from low to moderate intensity. What’s more, these diets can instruct your body to burn more fat, which can help you maintain muscle glycogen during exercise.

It is already proven that if you suffer from type 1 diabetes mellitus ( are insulin dependent) you should not try a ketogenic diet. There are interesting studies that have shown that those who decided to follow a diet high in animal fat and protein but lacking the carbohydrates amounts had a much higher risk when it comes to cardiovascular disease and even mortality.

Vitamin deficiency

Sadly, the human body can only store enough carbohydrates (glycogen) for approximately two hours of exercise. After this moment, fatigue and decreased operation may occur. People call it “hitting the wall” or sometimes “bonking.” To counteract this, most endurance athletes try a high carb diet only for the short term, the day before a race and consume carbohydrate foods or supplements through training. However, low carb diets do not have many carbohydrates, and therefore do not help maximize glycogen stores.

Although low carb diets appear to be safe in the short term, more research is needed for the side effects of these diets. In addition, the article in “The Lancet” notes that different low carb diets may include changing amounts of fiber, vitamins, and minerals, which can affect long-term health. Before making any significant changes to your diet, talk to your doctor to make sure your diet plan is safe.

Kidney damage

In addition, people with kidney disease can feel the kidney function getting worse with large protein intake; This disease affects more than 30 million people in the United States and most of them are unaware of it, according to the National Kidney Foundation. People at risk of kidney problems include those who have diabetes and hypertension.


Overweight people can be completely satisfied with a ketogenic diet, as well as those who suffer from diabetes or quite bad metabolic health.

Elite athletes might find it less suitable, along with people who want to gain some weight.

Also, like in case of any other diet, it needs to be constant to have its impact. The results will not appear right away.

Now, talking about a ketogenic diet, the powerful health benefits have been proved in nutrition along with weight loss achieved on it.