The ketogenic (keto) diet plan is a popular low-carbohydrate, high-fat eating plan often used in weight loss. Restricting carbohydrate intake leads to ketosis, a metabolic state in which the body burns fat as its primary energy source instead of sugar. However, this diet can pose risks in the long term, such as blood vessel damage, nutrient deficiencies, and weight regain.
Following the keto diet for an extended period can be hard due to its strict guidelines. You can have 50 grams of carbohydrates or less daily for at least two to three weeks and up to 6-12 months.
Many people on a keto diet—whether it’s to lose weight, manage diabetes, or other health reasons—can undo some of the benefits for their blood vessels. When you are in ketosis, your body burns fat for energy instead of sugar. A sudden increase in glucose (sugar) can place stress on the blood vessels and cause inflammation.
One small study found that high-sugar treats on a high-fat, low-carbohydrate diet can damage blood vessels. Keep in mind that the study sample size only included nine participants. Larger studies are needed to know how high-sugar snacks on the keto diet affect the blood vessels.
A long-term keto diet can affect the heart and arteries. One study found that people on low-carbohydrate diets are more likely to develop atrial fibrillation (AFib) compared to those who eat moderate amounts. AFib is a type of arrhythmia (irregular heart rhythm) that raises the risk of blood clots, stroke, and heart failure.
Low-carbohydrate dieters who consume large amounts of meat and dairy may have a higher risk of early death compared to others. Moderate consumption of carbohydrates and plant-based proteins can decrease this risk.
Most research is observational: It’s only been able to find associations with certain outcomes, not cause-and-effect relationships. There’s not enough long-term research to know what the keto diet does to the body over extended periods.
Limiting carbohydrates to 50 grams daily or less likely means cutting out unhealthy foods like white bread and refined sugar. It also means you may have to cut back on fruits and vegetables, which also contain carbohydrates.
This can be a concern, especially if you spend more than a few weeks on the keto diet. Fruits and vegetables are high in antioxidants and contain essential vitamins and minerals.
It may also be hard to get enough fiber while cutting back so much on carbohydrates since whole grains are one of the biggest sources of this important nutrient. A high-fiber diet can reduce your risk of heart disease, stroke, and type 2 diabetes. It can also help with digestive problems like constipation or diarrhea.
Some evidence suggests that the keto diet can damage athletes’ strength and fitness. One study found that participants performed worse on high-intensity cycling and running tasks after four days on a keto diet compared to those who ate a high-carbohydrate diet.
The keto diet can help athletes lose weight, which can be helpful for speed and endurance. Reduced athletic performance can still partially cancel out the benefits of weight loss. The body is in a more acidic state when it’s in ketosis, which can limit its ability to perform at peak levels.
Many keto diet variations recommend several stages, starting with an extremely low-carbohydrate phase for the first few months. You may transition to a more relaxed version that allows for more carbohydrates, often called lazy keto or keto cycling. The problem here is that weight regain is almost inevitable.
The keto diet can be a way to start losing weight, but many people cannot adhere to its strict guidelines for long periods. You may go into ketosis and lose weight, then come out and gain it back. This yo-yo pattern can be harmful. Weight fluctuations have been shown to increase the risk of early death.
The type of weight you gain back is also important. You will likely lose some muscle mass along with fat tissue on a high-fat diet. You will probably gain back more fat and less lean muscle. Reduced muscle looks and feels different on the body but also burns calories slowly.
The keto diet can be healthy in the short term as a way to jumpstart weight loss. It’s been shown to help with rapid weight loss and lower the risk of conditions like cancer, diabetes, and heart disease. The keto diet also helps treat neurological disorders like epilepsy, which causes frequent seizures.
It’s important to only follow the keto diet for short periods, as it’s not a sustainable lifestyle. A healthcare provider may recommend you try the keto diet for two to three weeks but no more than 6-12 months.
The paleo diet is a low-carbohydrate, high-fat alternative to the keto diet. It follows the eating patterns of humans during the Paleolithic era and largely includes game animals, plants, seafood, and tubers like potatoes.
A healthcare provider may recommend a balanced diet that’s low in processed foods as a more sustainable way to lose and maintain weight. The Mediterranean diet, which focuses on plant-based foods and healthy fats, has been shown to lower the risk of heart disease and regulate blood sugar.
The main hallmark of a keto diet is eating more fat and less carbohydrates. Some people claim it’s helpful for weight loss, but some evidence suggests the keto diet can lead to several health concerns. The keto diet can lead to nutrient deficiencies, weight regain, and increased disease risk.
A healthcare provider or nutritionist can help you determine what’s missing in your diet and what eating plan is sustainable. It’s important that you get plenty of nutrients and feel full from the food you eat.