Keto Diet: Research Reveals Health Risks

The ketogenic diet is a high-fat, moderate-protein, and low-carbohydrate eating pattern that has gained popularity in recent years. While it can lead to initial weight loss, scientific research suggests that it may not be effective for long-term health and weight loss goals and may even be harmful. The keto diet restricts several food groups, leading to potential nutrient deficiencies and adverse health effects. These include low blood sugar, digestive issues, impaired bone health, increased risk of chronic diseases and early death, kidney problems, and social isolation or disordered eating. It is particularly risky for individuals with certain medical conditions, such as kidney disease, diabetes, and heart ailments. Therefore, it is important to consult a healthcare professional before starting the keto diet, as it may not be suitable for everyone.

May lead to the keto flu

The keto flu is a collection of symptoms that some people experience when starting a ketogenic diet. Carb intake on the keto diet is typically limited to fewer than 50 grams per day, which can be a shock to the body. As the body's carb stores deplete and it switches to using ketones and fat for fuel, flu-like symptoms may occur. These include headaches, dizziness, fatigue, nausea, and constipation — due in part to dehydration and electrolyte imbalances that happen as the body adjusts to ketosis.

The keto flu is not a recognised medical condition, and a search on PubMed, the library of indexed medical research journals, yields no results. However, an internet search will bring up thousands of blogs and articles about the keto flu.

The symptoms may be caused by a detox factor, carb withdrawal, an immunologic reaction, or a change in the gut microbiome. The keto flu can happen to anyone who drastically and suddenly removes carbs from their diet. The body burns carbohydrates (glucose) for energy by default, so switching to a fat-burning process can confuse the body. When carb intake is drastically reduced, the body is depleted of stored glucose and instead turns to burning fatty acids for energy, which is the metabolic process of ketosis.

Symptoms of the keto flu generally begin within the first day or two of removing carbs. For most people, the keto flu can last a week or less, but in extreme cases, it can last up to a month. However, depending on genetics, some people may never experience the keto flu.

• Ease into the diet. Start with a typical low-carb diet and give your body time to adjust before going full keto.
• Stay hydrated. Dehydration is a huge factor in the keto flu, and drinking plenty of water can help with headaches and boost energy levels.
• Take an electrolyte supplement. The keto diet can lead to a loss of electrolytes, so adding plenty of electrolytes like salts, potassium, and magnesium to the diet can help stop cramps and nausea.
• Ensure adequate intake of healthy fats. Low calories can lead to keto flu symptoms, so it's important not to reduce calorie intake too much and to avoid going low-carb and low-fat at the same time. Increasing fat consumption can help speed up the transition to burning fat for fuel.
• Get plenty of rest. Taking an Epsom salt bath can help soothe and relax muscles, as well as improve electrolyte absorption.
• Try light exercise. Light exercise, such as restorative yoga, can help relieve muscle pain and tension and boost mood and motivation.

May stress your kidneys

The ketogenic diet is a low-carb, high-fat diet that is commonly used for weight loss. However, it may also carry health risks, one of which is the potential impact on kidney function. Here are some ways in which the keto diet may stress your kidneys:

Kidney Stones

The keto diet includes high-fat animal foods such as eggs, meat, and cheese, which are staples of the diet because they are low in carbs. However, consuming large amounts of these foods can increase the risk of kidney stones. This is because a high intake of animal products can make your blood and urine more acidic, leading to increased excretion of calcium in your urine. Some studies suggest that the keto diet also reduces the amount of citrate in your urine. Citrate can bind to calcium and prevent the formation of kidney stones, so reduced levels of citrate may increase the risk of their development.

Chronic Kidney Disease

The keto diet is not suitable for individuals with chronic kidney disease (CKD). The high intake of animal foods can lead to acid buildup in the blood, and weakened kidneys may be unable to remove this acid effectively. This can result in a state of acidosis, which can worsen the progression of CKD. Additionally, the keto diet is moderate to high in protein, while lower protein diets are often recommended for individuals with CKD.

Metabolic Acidosis

The keto diet can potentially worsen metabolic acidosis, a common complication of chronic kidney disease. Metabolic acidosis occurs when there is too much acid and too few bases (alkalis) in the body, and it can have negative effects on bone and muscle health.

Hyperfiltration

When you eat a high-protein diet, the kidneys must work harder due to increased blood flow to the filtrating unit of the kidney, known as hyperfiltration. This can lead to the progression of chronic kidney disease.

Albuminuria

High dietary acid load, generated by the consumption of high amounts of animal fat and protein, is associated with albuminuria, which is the loss of protein in urine. This can be a sign of kidney damage.

Nutrient Deficiencies

The keto diet restricts several nutrient-dense foods, including fruits, whole grains, and legumes. Over time, this may lead to nutrient deficiencies, including deficiencies in potassium and magnesium, which are important for kidney health.

May cause digestive issues and changes in gut bacteria

The ketogenic diet is a high-fat, very low-carb diet that has been shown to benefit cholesterol levels, blood sugar control, weight loss, and brain health. However, it may also cause digestive issues and changes in gut bacteria.

The keto diet eliminates high-carb foods like fruits, starchy vegetables, grains, and legumes, many of which are also high in fibre, an essential nutrient for digestion. Insufficient fibre intake could increase the risk of constipation and other digestive disorders.

Research suggests that the keto diet could also damage the concentration and composition of gut bacteria. A 6-month study in 217 people linked a high-fat diet to unfavourable gut changes, including increased inflammation and reduced beneficial fatty acids. Another study in 23 children with epilepsy showed that 3 months of the keto diet damaged gut microbiome composition compared to a control group.

A 2020 study published in Cell found that shifting between standard and ketogenic diets dramatically changed the proportions of common gut microbial phyla Actinobacteria, Bacteroidetes, and Firmicutes in participants' guts, including significant changes in 19 different bacterial genera. The study also showed that the ketogenic diet led to a decrease in Bifidobacteria, a common probiotic.

The high fat and low carb content of the keto diet may also lead to other gastrointestinal symptoms such as nausea, bloating, and diarrhoea. Consuming more dairy when starting a keto diet may also lead to diarrhoea and other gastrointestinal issues.

While the keto diet may have benefits for weight loss and other aspects of health, it is important to consider the potential impact on digestive health and gut bacteria. More research is needed to fully understand the effects of the keto diet on gut health.

May lead to nutrient deficiencies

The keto diet is a high-fat, moderate protein, and low-carbohydrate diet that forces the body into a state of ketosis, where fat is burned for energy instead of carbohydrates. While this diet has been popular for weight loss, it may lead to nutrient deficiencies, especially in the long term. Here are some of the key nutrients that may be lacking:

Calcium

People on long-term keto diets often lose too much calcium through their urine, and the high-fat content of the diet can increase the body's acid production, which can lead to lower bone density. Additionally, the restriction of calcium-rich foods like fruits, vegetables, dairy, and grains can further contribute to calcium deficiency.

Magnesium

Magnesium is another mineral that has been observed to decrease on a long-term keto diet. This mineral is essential for energy production and proper nerve and brain function. Deficiency can lead to various health issues, including heart disease and migraines. Symptoms of magnesium deficiency include muscle cramps, headaches, anxiety, nervousness, and constipation.

Iron

Iron is necessary for energy production and the formation of red blood cells, and a deficiency can cause fatigue and breathing difficulties during exercise. The keto diet may reduce iron absorption due to the high amounts of fat, and it typically restricts iron-rich foods like grains and legumes.

Selenium

Selenium is a mineral that plays a crucial role in heart health, reproduction, thyroid function, and protecting the body from oxidative stress. The keto diet, which is often low in selenium-rich foods, can lead to selenium deficiency, especially in the long term.

Vitamins and Other Micronutrients

The restriction of certain food groups on the keto diet can lead to deficiencies in various vitamins and micronutrients. These include folate (B9), biotin (B7), vitamin A, vitamin E, vitamin D, chromium, iodine, and molybdenum. These nutrients are essential for various bodily functions, and their deficiency can have adverse health effects.

To mitigate these potential deficiencies, it is recommended to include nutrient-dense foods in your diet, such as grass-fed meat, poultry, wild-caught fish, leafy greens, nuts, and seeds. Additionally, supplementation with specific vitamins and minerals may be necessary under the guidance of a healthcare professional.

May cause dangerously low blood sugar

The ketogenic diet is a high-fat, moderate-protein, and low-carbohydrate eating pattern. Carbohydrate intake is typically restricted to fewer than 50 grams per day, and some people adhere to less than 20 grams per day. This diet encourages the body to enter a state of ketosis, where it burns fat for energy instead of carbohydrates. While this can be beneficial for weight loss and managing type 2 diabetes, it can also lead to dangerously low blood sugar levels, also known as hypoglycemia.

Hypoglycemia is a condition where blood sugar levels drop below the normal range of about 70 milligrams per deciliter (mg/dL). This can be particularly dangerous for individuals with diabetes, but it can also occur in people without diabetes who are on low-carbohydrate diets like keto. Symptoms of hypoglycemia include weakness, shakiness, moist skin or sweating, nightmares, bad dreams, restless sleep, headaches, seizures, fruity-smelling breath, unexplained tantrums or crying, dizziness, fatigue, and difficulty concentrating.

Individuals with type 1 diabetes are at a particularly high risk of hypoglycemic episodes while on a keto diet. A study of 11 adults with type 1 diabetes who followed a ketogenic diet for over two years found that they experienced a median of almost one low blood sugar event per day. This is because their insulin regimens and oral hypoglycemic agents may need to be adjusted when starting a keto diet. Without proper management, hypoglycemia can lead to coma and even death.

Even those without diabetes can experience hypoglycemia on a keto diet, especially if they have been fasting or are sick. Children are the most affected by this condition, and it can be worse if they are dehydrated due to diarrhea or vomiting. However, most children will outgrow hypoglycemia by the time they are six years old, and it usually does not cause any permanent harm.

For those experiencing hypoglycemia, the treatment is simple: consume sugar or glucose in the form of juice or other sugary foods and drinks. Blood sugar levels should increase within 15 to 20 minutes. If they do not, or if the person cannot eat or drink due to vomiting, sluggishness, or seizures, seek emergency medical treatment to receive intravenous fluids containing glucose.

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