Is the Keto Diet Safe? What are the Risks? - UChicago Medicine (2024)

Fad diets often come with big promises of weight loss and optimum health, but at what risks?

What is the keto diet?

Rachel Kleinman, RDN, LDN, clinical dietitian, says the keto diet is primarily used to manage seizures in children with epilepsy. Research on the diet’s effectiveness in treating obesity or diabetes is limited.

The ketogenic or keto diet, which has gained popularity in the last several years, is extremely strict and difficult to maintain.

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What is ketosis?

Ketosis is a metabolic adaptation to allow the body to survive in a period of famine. Your body will break down ketone bodies, a type of fuel the liver produces from fat, instead of sugar or glucose from carbohydrates.

To achieve ketosis, the diet requires you eat 75 percent of your calories from fat, compared to 20-35 percent normally. It also requires 5 percent of calories from carbohydrates, about 20-50 grams per day, and 15 percent of calories from protein. Kleinman said it takes about 72 hours for ketosis to kick in. It’s really an all or nothing diet.

People following the keto diet should be eating foods like fatty fish, eggs, dairy, meat, butter, oils, nuts, seeds and low-carb vegetables. “Fat bombs” like unsweetened chocolate or coconut oil can help people reach their daily goals for fat intake. Keto-compliant foods like red meats and nuts can be costly. Keto-branded products like keto coffee and other supplemental products are also both costly and unnecessary.

Is the keto diet healthy?

Wellness dietitian Mary Condon, RN, LDN, says the keto diet may result in weight loss and lower blood sugars, but it’s a quick fix. “More often than not, it’s not sustainable. Oftentimes weight gain may come back, and you’ll gain more than what you lost.”

Condon says you should always consult your primary care doctor before starting any new diet.

What are the dangers of the keto diet?

“If you are on diabetic medication that causes low blood sugar, those meds may need to be adjusted within a few days,” Condon says. “There are heart-healthy sources of fat, however if that person is not educated on heart-healthy sources of fat, they may consume excessive amounts of saturated fats that can increase your risk of heart disease.”

Is the keto diet safe?

The keto diet could cause low blood pressure, kidney stones, constipation, nutrient deficiencies and an increased risk of heart disease. Strict diets like keto could also cause social isolation or disordered eating. Keto is not safe for those with any conditions involving their pancreas, liver, thyroid or gallbladder.

Someone new to the keto diet can also experience what’s called the “keto flu” with symptoms like upset stomach, dizziness, decreased energy, and mood swings caused by your body adapting to ketosis.

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Is the keto diet bad for you?

Both Condon and Kleinman say they wouldn’t recommend the keto diet to their patients because it is ultimately not realistic or sustainable. The diet restricts fresh fruits and vegetables, whole grains and low fat dairy that can help with long term weight loss and overall health.

“There’s not one diet that’s good for everyone,” Kleinman says. “Do your research, consult a dietitian, discuss with your doctor, and make sure you’re being safe.”

Is the Keto Diet Safe? What are the Risks? - UChicago Medicine (2024)

FAQs

Is the Keto Diet Safe? What are the Risks? - UChicago Medicine? ›

The keto diet could cause low blood pressure, kidney stones, constipation, nutrient deficiencies and an increased risk of heart disease. Strict diets like keto could also cause social isolation or disordered eating. Keto is not safe for those with any conditions involving their pancreas, liver, thyroid or gallbladder.

What are the risks of the keto diet? ›

Common short-term side effects resulting from the initiation of KD have been referred to as “keto flu,” which encompasses symptoms including fatigue, headache, dizziness, nausea, vomiting, constipation, and low exercise tolerance [6].

Is the keto diet medically approved? ›

It's advertised as a weight-loss wonder, but this eating plan is actually a medical diet that comes with serious risks. In the world of weight-loss diets, low-carbohydrate, high-protein eating plans often grab attention.

What are the advantages and disadvantages of a keto diet? ›

Ketosis is a metabolic state that occurs when your body burns fat for energy instead of glucose. The keto diet has many possible benefits including potential weight loss, increased energy and treating chronic illness. However, the diet can produce side effects including “keto” breath and constipation.

Is keto a healthy choice? ›

The ketogenic diet's increasing popularity is largely due to its potential benefits for weight loss and blood sugar control ( 1 , 2 , 3). Early evidence also suggests that this low carb, high fat diet may help treat certain cancers, Alzheimer's disease, and other health conditions.

Why does keto have a bad reputation? ›

While the theory behind fat loss resulting from a keto diet is appealing, it does not hold up well in practice. While keto dieters often experience a satisfying initial weight loss, this is a short-term result from the loss of body water that accompanies lower carbohydrate intake, not fat loss.

Is keto bad for your kidneys? ›

The ketogenic (keto) diet has helped many Americans lose weight; however, it may also contribute to an increased decline in kidney function for those with kidney disease. The Keto Diet is characterized by very low-carbohydrate, modest in protein meals that focus heavily on fat intake.

Do ketones cause kidney stones? ›

Eating a lot of animal foods on the keto diet can lead to more acidic urine and a higher risk of kidney stones. This acidic state can also worsen the progression of chronic kidney disease.

Is a keto diet safe for seniors? ›

People over 50 may have success on the keto diet, because it has the potential to promote weight loss, control blood sugar, and possibly protect against heart disease. But this eating plan does have risks, and you should always check with your doctor or a licensed nutritionist before you start any new diet.

Is keto bad for cholesterol? ›

Healthier fats — called monounsaturated and polyunsaturated fats — are found in foods like eggs, fish, and nuts. Additionally, keto can lead to a sudden surge in LDL and triglycerides, the “bad” cholesterol, when the diet is initiated, a surge that may level out after weeks and months.

How long can you be on a keto diet? ›

Following the keto diet for an extended period of time can be difficult, and even some of its top proponents warn against sticking to its strict guidelines. This includes cutting back carbohydrates to 50 grams a day or less, for at least two to three weeks up to six to 12 months, per the National Library of Medicine.

Is a keto diet safe if you have no gallbladder? ›

This is a common question, given the higher fat content of the keto diet and the general recommendation of a low-fat diet for people who've had their gallbladder removed. Still, the answer is yes, you can follow a keto diet after you've recovered from a gallbladder removal surgery.

Are keto diets healthy yes or no? ›

Studies have now shown that the diet can have benefits for a wide variety of different health conditions: Heart disease. The ketogenic diet can help improve risk factors like body fat, HDL (good) cholesterol levels, blood pressure, and blood sugar ( 28 , 29 ).

Why does blood pressure drop on a keto diet? ›

If you make no lifestyle change this trend, and its associated risks, will continue. When you switch to a ketogenic diet, your body releases little insulin so less potassium is stored, less water is retained, blood volume goes down and your blood pressure decreases.

Are bananas keto? ›

Bananas may be great for muscle recovery, reducing bloat, and calming an upset stomach, but they're on the list of foods you can't eat on the keto diet. With 25g of carbs per 100g serving, bananas are too high in carbs.

Who would not benefit from a keto diet? ›

In particular, it's not recommended for pregnant and breastfeeding women or those with certain health conditions, like IBS, osteoporosis, or kidney problems. The keto diet can improve markers of health — such as cholesterol and other blood fat levels — in people with obesity without major side effects.

How long can you stay in ketosis safely? ›

Following the keto diet for an extended period of time can be difficult, and even some of its top proponents warn against sticking to its strict guidelines. This includes cutting back carbohydrates to 50 grams a day or less, for at least two to three weeks up to six to 12 months, per the National Library of Medicine.

What are the dangers of a low-carb diet? ›

Complications such as heart arrhythmias, cardiac contractile function impairment, sudden death, osteoporosis, kidney damage, increased cancer risk, impairment of physical activity and lipid abnormalities can all be linked to long-term restriction of carbohydrates in the diet.

What happens if you eat no carbs for a week? ›

Severe carb limits can cause your body to break down fat into ketones for energy. This is called ketosis. Ketosis can cause side effects such as bad breath, headache, fatigue and weakness. It's not clear what kind of possible long-term health risks a low-carb diet may pose.

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