The ketogenic diet, characterized by very low carbohydrate, moderate protein, and high-fat intake, has gained popularity as a weight-loss strategy and a potential management tool for type 2 diabetes. While it may seem like a recent trend, the ketogenic diet has been around since the 1920s, initially used as a treatment for epilepsy. The diet aims to induce "ketosis," a metabolic state where the body burns fat for energy instead of glucose, producing ketone bodies as an alternative fuel source. Despite potential benefits, the ketogenic diet's impact on kidney health remains a topic of discussion and requires careful consideration, especially for individuals with pre-existing kidney conditions.
What is the Keto Diet?
The ketogenic diet typically reduces carbohydrate intake to less than 50 grams per day while moderately increasing protein and fat intake. Roughly, 70 to 80 percent of calories come from fat, about 20 percent from protein, and as little as 5 percent from carbs. This strict macronutrient ratio forces the body to switch its primary fuel source from glucose to fat.
When carbohydrate intake is drastically reduced, insulin secretion decreases, and the body enters a breakdown state. The body's glycogen reserves are depleted, compelling various metabolic adjustments. Two metabolic processes, gluconeogenesis and ketogenesis, come into play. Gluconeogenesis is the internal production of glucose, and when glucose levels are insufficient, ketogenesis starts, providing energy in the form of ketone bodies.
Acetoacetate, produced during the metabolism of fatty acids, is then changed into acetone and beta-hydroxybutyrate. Nutritional ketosis refers to the state where there is an increased level of ketone bodies. The body's metabolism remains in a state of ketosis for as long as it is denied carbohydrates.
Potential Benefits of the Keto Diet
- Weight Loss: The ketogenic diet can be effective for quick weight loss, with some individuals experiencing a weight loss of up to 10 pounds in just a couple of weeks. Weight loss occurs due to water losses that occur as carbohydrate stores are depleted.
- Epilepsy Management: The keto diet has a long history of use in managing refractory epilepsy, especially in children. Hormones released and suppressed during fasting and eating are also involved in initiating and suppressing seizure activities.
- Type 2 Diabetes Management: Preliminary research suggests that the keto diet may be safe and effective for certain people with type 2 diabetes, as it may help control HbA1C levels.
- Other Potential Benefits: The keto diet is being studied for reducing symptoms for patients with progressive neurological disorders like Parkinson’s disease. Studies in animal models of autosomal dominant polycystic kidney disease (ADPKD) showed the extremely positive effects of a ketogenic diet, inhibiting both cyst growth and the loss of kidney function.
Potential Risks and Side Effects of the Keto Diet
Despite the potential benefits, the ketogenic diet can pose several risks, especially concerning kidney health:
Read also: Easy Low-Carb Cheese Crackers
- Kidney Stones: Kidney stones are a well-noted potential side effect of the ketogenic diet. High intake of animal proteins makes urine more acidic and increases calcium and uric acid levels, increasing the risk of kidney stones and gout.
- Kidney Stress: The ketogenic diet can be dangerous for people with kidney disease, as they often need to consume a low-protein diet, which may not align with the type of keto being followed.
- Acute Kidney Injury: Few cases exist in the literature regarding the keto diet causing acute kidney injury. High Dietary acid load generated by the consumption of high animal fat and protein is associated with albuminuria (losing protein in urine) and the onset of chronic kidney disease.
- Hyperfiltration: When you eat a high-protein diet, the kidney must work harder because of increased blood flow to the filtrating unit of the kidney called Hyperfiltration, which leads to the progression of chronic kidney disease.
- Muscle Loss: Small studies suggest that people on the ketogenic diet lose muscle even when they continue resistance training. Loss of muscle mass as we age has a number of serious consequences, decreasing functional strength and heightening the risk of falls.
- Low Blood Sugar: While a keto diet may help control HbA1C levels, the diet may also cause episodes of hypoglycemia, which is a dangerous drop in blood sugar, especially for those on insulin.
- Yo-Yo Dieting: Sticking with such a restrictive diet long-term can be difficult, however, and leave you open to weight re-gain, and the cycle of yo-yo dieting.
- Dehydration and Electrolyte Loss: The brain’s favorite fuel is glucose, which is most easily created from carbohydrates. In very low carb diets, the brain has to adjust to using ketones from digested fats for energy. To add to this discomfort, your kidneys release more electrolytes as insulin levels fall.
- Nutrient Deficiencies: When carbohydrate intake is low, fiber consumption tends to be low, too, which can lead to constipation. Another possible nutrient deficiency is potassium.
- Bowel Problems: Many of the richest sources of fiber, like beans, fruit, and whole grains, are restricted on the ketogenic diet, leading to constipation. Diarrhea can also crop up as a side effect of the keto diet - especially in the first few weeks.
- Bad Breath: Acetone is a by-product of ketosis and is eliminated mostly through the lungs and the breath, causing fruity-smelling bad breath.
- Menstrual Irregularities: Periods may become irregular or completely stop on the keto diet due to rapid weight loss, which happens because of drops in gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, estrogen, and progesterone.
- Low Blood Sodium: When you start the keto diet, you lose sodium and other electrolytes in the urine due to reductions in insulin, contributing to symptoms of keto flu.
- High Cholesterol and Heart Disease Risk: The ketogenic diet doesn’t put a cap on saturated fat, which has been associated with adverse health effects.
Keto and Polycystic Kidney Disease (PKD)
In 2019, studies in animal models of autosomal dominant polycystic kidney disease (ADPKD) showed the extremely positive effects of a ketogenic diet. This finding attracted a lot of attention among nephrologists, scientists, and patients. The change in diet inhibited both cyst growth and the loss of kidney function.
Recently published in the renowned Cell Reports Medicine, the KETO-ADPKD study addressed this issue. The ketogenic diet leads to a metabolic change in which ketone bodies are formed as a metabolic product, hence the name. In a nutshell, in order to achieve this metabolic shift, the amount of carbohydrates (i.e. sugar) is significantly reduced and the amount of fat in the diet is greatly increased.
Normally, polycystic kidneys continue growing over time. With the study’s control group, participants who continued eating as usual, this was also the case. On the ketogenic diet, the kidney volume decreased. In contrast, kidney function increased over the course of the three months on a ketogenic diet.
Considerations for Individuals with Kidney Disease
For those with or at risk for kidney disease, one of the best ways to maintain a healthy weight is to adopt a healthy lifestyle with balanced and portioned meals. This includes adequate amounts of protein, carbohydrates, fat, fiber, and other micronutrients.
People with kidney disease or a history of disordered eating should avoid the diet, and people with type 1 diabetes may want to avoid it as well. Anyone who is pregnant or lactating should talk to their healthcare practitioner before trying any new diet, including keto.
Read also: Keto Calorie Counting: A Detailed Guide
The Importance of Consulting Professionals
If you’re thinking about trying the ketogenic diet, consult your doctor first - whether or not you have preexisting health conditions. Consult a registered dietitian nutritionist, a professional who can work with you to create a meal plan you can stick to.
Read also: Magnesium Supplements for Keto