Hypertension, or high blood pressure, can be managed through a number of lifestyle changes, including eating a healthy diet. The ketogenic diet (KD) has gained popularity as a potential intervention for weight loss and metabolic health. However, the relationship between the keto diet and blood pressure is complex and warrants careful consideration. This article aims to provide a comprehensive overview of the current understanding of how the keto diet may impact blood pressure, considering both potential benefits and risks.
What is the Keto Diet?
A ketogenic diet (KD) is a high-fat (providing a range of 55 to 90% calories as fat), adequate protein (accounts for 30-35% of the daily caloric requirement supplied; minimum of 1 g/kg of protein), low-carbohydrate diet (only 5-10% of total calories are provided by carbohydrates, less than 50 g/day). The keto diet reduces your total carb intake to less than 50 grams a day. This is the equivalent of a cup of white rice. The keto diet excludes carb-rich foods like grains, beans, fruits and starchy vegetables.
The diet's extreme carbohydrate restrictions may lead people to shun most vegetables and fruits and consume large amounts of leafy greens. When these stores are full, they are converted into fat. In this state, your body breaks down fats into molecules called ketones. Ketones serve as an alternative fuel source. Ketosis is a metabolic adaptation to allow the body to survive in a period of famine.
Variations of Low-Carbohydrate Diets
Because the keto diet is so restricted, you’re not receiving the nutrients - vitamins, minerals, fibers - that you get from fresh fruits, legumes, vegetables and whole grains,” says Dr. Ring. People report feeling foggy, irritable, nauseous and tired. It is important to note that “ketogenic diets” are not a registered unique specific protocol for the “KD”. Different diet methodologies are offered to patients depending on (i) level of carbohydrate restriction, (ii) protein contribution, (iii) quality of fat (animal and/or vegetable). Moreover, these ketogenic diets should be considered part of the larger group of low carbohydrate diets (LCD), including in this term a very heterogeneous group of nutritional regimens, without a univocal definition, which have as a key common denominator a low content of carbohydrates.
Some examples of LCDs are the Atkins diet , the Zone diet, the South Beach diet, and the Paleo diet. Given that many epidemiologic analyses conducted on different large groups of subjects have established that the average daily intake of macronutrients is at least 45% provided by carbohydrates , the definition of LCD should be attributed to a diet that provides between 50 and 150 g of carbohydrates per day (equivalent to a percentage > 10% and <30%) while we can talk of KD for a diet that provides a <50 g per day of carbohydrates (equivalent to a percentage < 10%) although very often only a daily intake < 20 g is allowed.
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Potential Benefits of Keto on Blood Pressure
In consideration of its encouraging effects on carbohydrate metabolism and glucose levels, the scientific community’s interest in KD was headed towards finding methods to combat the worsening obesity epidemic . Obesity, as well as many other diseases like diabetes mellitus and cardiovascular diseases (CVDs), is a condition with several contributing causes including poor dietary habits and sedentary physical activity behaviors . KD substantially induces a metabolic framework that mimics starvation: during a short-limited period of nutrient deprivation or low carbohydrate availability, the primary source of carbohydrate reserve is glycogen, a branched polymer of glucose serving as a store of energy in times of nutritional sufficiency for utilization in times of need , which provides only 12- to 14-h energy reserve . Therefore, when fasting is prolonged and glycogen reserves are depleted, in order to supply the unavailable dietary glucose, the gluconeogenesis process is stimulated, and the primary carbon skeletons required for the synthesis of glucose come from lactic acid, glycerol, and the amino acids alanine and glutamine .
Several studies suggest that the keto diet may have a positive impact on blood pressure, particularly in the short term. A new study offers further evidence that both the Mediterranean and keto diets can help lower a person’s blood pressure and improve cardiovascular health measurements in people who have obesity or overweight. A study published in April 2024 reported that following the Mediterranean diet was linked to a lower risk for high blood pressure. Another study published in July 2019 showed that following a low carbohydrate diet like the keto diet helped lower blood pressure readings in people with type 2 diabetes. At the study’s conclusion, researchers found that participants in both diet groups experienced a decrease in blood pressure and weight loss after three months. Scientists also found that participants in both diet groups experienced an increase in their fat-free mass - the total mass of the body excluding fat - and a decrease in their body fat, blood lipid levels, and insulin concentrations.
Mechanisms of Action
A drop in blood pressure on a ketogenic diet can occur for several reasons related to the diet’s impact on fluid and electrolyte balance. When you start a ketogenic diet, which is very low in carbohydrates and high in fats, your body undergoes significant metabolic changes. Initially, as your body shifts from using glucose (carbs) for energy to using fat and ketones, it starts to excrete more water. This is because glycogen, the stored form of glucose in your muscles and liver, binds with water. When glycogen levels drop on a keto diet, water is also released and excreted, leading to a reduction in blood volume.
The loss of water and sodium can lead to a decrease in blood pressure. Sodium plays a crucial role in maintaining fluid balance and blood pressure. On a keto diet, lower insulin levels lead to reduced sodium retention by the kidneys, which further contributes to the decrease in blood pressure. This change can make you more susceptible to lower blood pressure, especially during the early stages of the diet.
Potential Risks and Considerations
Despite the potential benefits, the keto diet also poses certain risks that need to be considered, particularly in relation to blood pressure and overall cardiovascular health.
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Impact on Cholesterol Levels
The review summarized the current evidence on how keto diets may raise heart disease risk. Ketogenic diets appear to lower blood levels of triglycerides but raise levels of artery-clogging LDL cholesterol. The high-fat nature of the diet could also have negative impacts on heart health. The American Heart Association recommends limiting saturated fat intake to less than 6%. “In practice, many people eat high amounts of saturated fats, which could increase your risk of heart disease,” says Dr. Cheema. “You may be eating a lot of fatty meat thinking it’s a good thing for you because it's high in fat. This can dramatically alter your lipid profile. While high-fat diets can elevate LDL (“bad”) cholesterol, the type of saturated fat matters. The bottom line is that having more fats in your diet can lead to higher cholesterol. “We know that higher cholesterol tends to increase your chances of heart attacks and strokes,” says Dr. Cheema.
Electrolyte Imbalance and Low Blood Pressure
Additionally, the keto diet may also affect other electrolytes like potassium and magnesium. If your diet lacks sufficient sources of these essential minerals, it can further impact blood pressure regulation. Potassium and magnesium are vital for maintaining cardiovascular health and proper muscle function, including the muscles involved in regulating blood pressure.The keto diet can cause your blood pressure to drop in the short term due to a reduction in blood volume and changes in your fluid balance. Symptoms of low blood pressure include dizziness, lightheadedness or fainting, especially when standing up quickly.
Nutrient Deficiencies and Long-Term Sustainability
“Because the keto diet is so restricted, you’re not receiving the nutrients - vitamins, minerals, fibers - that you get from fresh fruits, legumes, vegetables and whole grains,” says Dr. Ring. People report feeling foggy, irritable, nauseous and tired. “In particular, low fiber intake can disrupt gut microbiota and lead to chronic constipation, while inadequate magnesium, vitamin C and potassium can contribute to muscle cramps, fatigue and weakened immune function,” explains Dr. Because of the stringent food restrictions, many find the keto diet hard to stick to. “The ketogenic diet can be effective for weight loss when used in a short time period followed by the adoption of healthier eating habits,” says Baljash Singh Cheema, MD, a cardiologist at Northwestern Medicine Bluhm Cardiovascular Institute. “However, we know in studies of these types of diets that once people stop following that diet, they regain at least half of the weight that they lost. Strict diets like keto could also cause social isolation or disordered eating. Both Condon and Kleinman say they wouldn’t recommend the keto diet to their patients because it is ultimately not realistic or sustainable.
The "Keto Flu"
One of the main short-term side effects of the KDs is the so-called “keto flu” , also often referred to as “keto-induction” or “keto-adaptation” , a cluster of transient symptoms generally reported as occurring within the first few weeks of KD, predominantly constipation, headache, halitosis, muscle cramps, diarrhoea, vomiting, and general weakness . To date the cause of the occurrence of keto flu is not fully explained and very few authors have addressed this condition .
The Importance of Individualized Approaches
There’s no ‘one-size-fits-all’ when it comes to dietary patterns - unless it’s a kitchen apron. No one diet fits all, and what works for one person may not work for another. “Meeting with a registered dietitian nutritionist (RDN) is recommended to further explore which dietary pattern may be most appropriate for an individual’s needs, current health condition, preferences, goals, genetics and lifestyle,” Richard said. “RDNs are trained to bridge the gap between science and everyday life. If you’re looking to manage weight or blood pressure in a way that’s realistic and sustainable, working with an RDN can be a game-changer.” It is also important to consider if the specific dietary pattern is sustainable for a long period of time and can be a lifestyle versus a controlled experiment or ‘temporary fix’,” she continued. “Think of dietary patterns like a playlist - the right mix can set the tone for a healthier rhythm in your body and the days ahead.”
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Dietary Recommendations
Richard suggested honing in on increasing foods rich in nutrients with many health benefits, such as:
- Healthy fats like olives, extra-virgin olive oil, avocados, nuts, and seeds.
- Non-starchy vegetables such as leafy greens, beets, peppers, onions, garlic, scallions, tomatoes, cabbage, and Brussels sprouts.
- Herbs such as chives, basil, mint, rosemary, thyme, and sage.
- Proteins from plants and animals, such as goat cheese, yogurt, beans and lentils, fish, hummus, and tzatziki.
- High fiber foods from whole grains like oats, whole wheat, and rye, and fresh fruits in season such as peaches, plums, apples, grapes, berries, pears, oranges, figs, dates, and cherries.
- Incorporation of green, black, white, or herbal teas.
Managing Low Blood Pressure on Keto
Symptoms of low blood pressure on a keto diet might include dizziness, lightheadedness, or fainting, particularly when standing up quickly or after prolonged periods of sitting. These symptoms occur because of the reduced blood volume and changes in fluid balance.
To manage these effects, it’s important to stay well-hydrated and ensure adequate intake of electrolytes. Consuming foods rich in potassium and magnesium, or taking supplements if necessary, can help maintain balance. Adding a bit more salt to your food may also help retain sodium and stabilize blood pressure, but this should be done under the guidance of a healthcare provider.
When to Seek Medical Advice
If you experience persistent or severe symptoms, or if blood pressure drops significantly, it’s crucial to consult with a healthcare provider. The keto diet may not be appropriate for everyone, specifically people with kidney disease. “Although more research is needed in that area, there is some suggestion that it can make kidney disease worse over time,” says Dr. Following a keto diet can also cause your blood sugar to drop, which can be dangerous for people living with diabetes. Common symptoms of low blood sugar include weakness or shaking, sweating, a fast heartbeat and dizziness.
Other Considerations
While the diet may dramatically reduce fat mass and weight over the short term, there is scarce evidence for any long-term benefit. The diet's extreme carbohydrate restrictions may lead people to shun most vegetables and fruits and consume large amounts of leafy greens. But the vitamin K in these foods may interfere with the anti-clotting drug warfarin taken by some heart patients. Share on PinterestKeto vs. Mediterranean: Which diet gets better results for weight loss and blood pressure? Design by MNT; Photography by Alexander Spatari/Getty Images & Westend61/Getty Images
The Mediterranean Diet as an Alternative
Past studies have linked the Mediterranean and ketogenic diets as a way to help lower blood pressure. One area where researchers reported a difference between the Mediterranean and keto diets. They reported that participants following the keto diet had a higher level of “nocturnal dipping” than those in the keto group. A 10-20% dip in blood pressure while you sleep is considered normal. Past studies show that not experiencing nocturnal dipping, or the reverse of it, known as nocturnal hypertension, can increase a person’s risk for cardiovascular disease.
The Role of Processed Foods
“What is it about these two types of diets that are helpful?,” he asked. “Is it reducing processed foods or is it more reducing the carbohydrates and sugars? So there are some differences between the diets, and trying to define further what is optimal between these two diets.” and other westernized countries, so the more we can find ways to combat that, find foods that are going to help people lose weight and head to a healthier diet, then maybe some of these larger food manufacturers will start shifting their focus to foods that just taste good to foods that may actually be helpful,” Ali continued.