Is The Keto Diet Safe Long-Term? New Study Raises Alarming Risks

The ketogenic (keto) diet has become hugely popular, admired for its promise of rapid weight loss, better blood sugar regulation, and improved energy. Many people follow it as a lifestyle, convinced of its long-term benefits. But a striking new study from University of Utah Health is raising strong caution flags. It reveals that when the diet is extended, it may come with serious metabolic risks. In lab mice, months of very-high-fat, very-low-carb feeding triggered fatty liver disease, impaired insulin response, and other signs of organ stress.

These findings suggest that while the keto diet may appear safe, and even highly effective, in the short run, chronic adherence could bring hidden costs. Medical experts say the results deserve attention because they challenge the assumption that keto is harmless when followed indefinitely.

What The New Study Found

Researchers at University of Utah Health conducted a long-term keto diet study in mice, published in Science Advances. Over several months (equivalent to years in human lifespan), they observed surprising and concerning changes:

• Fatty liver (hepatic steatosis): Male mice especially developed a buildup of fat in liver cells, a precursor to serious liver disease.
• Blood sugar dysregulation: After fasting, the keto-fed mice showed very low glucose and insulin. But when given even a small dose of carbohydrates, their blood sugar spiked sharply and remained high for a long period.
• Pancreatic stress: Scientists found that insulin-producing beta cells in the pancreas were under distress. The high-fat diet disrupted how these cells processed proteins, reducing their ability to secrete insulin.
• Some recovery possible: Encouragingly, many of these metabolic issues reversed when the mice were taken off the keto diet, suggesting that not all damage may be permanent, though long-term safety is still in question.

These findings raise important questions about whether keto's effects, studied widely in short-term human trials, truly reflect its long-term impact.

Other Known Risks Of Long-Term Keto Diet

The Utah study is not the only warning sign. Medical literature and reviews also highlight other possible side effects:

Liver and Cardiovascular Stress

• High-fat diets may elevate blood lipids (cholesterol, triglycerides), potentially increasing risk of heart disease.
• Over time, fat accumulation in the liver may lead to liver dysfunction.

Kidney Problems and Mineral Imbalance

• Keto diets can increase the risk of kidney stones, due to changes in urine chemistry.
• There may be deficiencies in key vitamins and minerals (because of severe carbohydrate restriction), raising concern for long-term nutritional health.

Glucose and Insulin Issues

• Even in non-animal-model studies, long-term keto can impair glucose tolerance, echoing what the Utah mice study found.
• In the Utah study, beta-cell stress was shown to be a key mechanism.

Possible Cellular Aging

Some research suggests long-term very-high-fat diets may contribute to the build-up of senescent (aged) cells in organs such as the kidneys and heart, which is linked to chronic inflammation and tissue damage.

Short-Term Side Effects Or "Keto Flu"

• Common early symptoms include headache, fatigue, nausea, constipation, dizziness and "keto flu."
• Electrolyte imbalances, dehydration and low intake of certain nutrients may compound these issues.

Why The New Study Is Important

While previous human studies, especially in people using keto for weight-loss or medical treatment, have mainly focused on short-term effects, this new research pushes the field to ask: What happens if someone stays on keto for years? The mouse model results suggest that key metabolic organs (liver, pancreas) may be under stress that's not evident in simple weight-loss metrics.

Moreover, the reversibility seen in mice gives a glimmer of hope, but also underscores that consistent medical supervision and periodic re-evaluation are vital.

Who Might Be At Higher Risk

Not everyone on a keto diet will experience harmful effects in the same way. Risks may be higher for:

• People staying on keto continuously for many years.
• Those with underlying fatty liver disease or metabolic vulnerabilities.
• Individuals not being monitored by healthcare professionals.
• People using highly restrictive or unbalanced keto versions (e.g., very high saturated fat intake).

Guidance For Safe Use

Given these potential long-term risks, health experts are recommending caution:

• Talk to a healthcare provider before starting keto, especially for long-term use.
• Avoid extreme, unmonitored versions of the diet, particularly those relying heavily on saturated fat.
• Limit duration or cycle the diet: Some may choose to follow keto short-term (for medical or weight-loss goals) rather than indefinitely.
• Monitor health parameters: Regular checks for liver function, blood lipids, glucose regulation, and kidney health.
• Ensure nutritional balance: Use supplements if needed, make room for vegetables, and watch for deficiencies.
• Be open to switching: If harmful signs appear, be prepared to adjust or stop the diet under professional guidance.

Not All Studies Agree: Mixed Evidence

It's worth noting that not all long-term keto research shows harm. A human study (in obese patients) maintained for 24 weeks reported improvements in weight, triglycerides, LDL, and glucose, without major side effects. This suggests that risks may depend on diet composition, duration, individual health status, and how strictly the diet is followed.

The new study from University of Utah Health is a timely reminder that what looks beneficial in the short term might carry costs over years. Keto, or any extreme diet, is not without trade-offs. While rapid weight loss and metabolic gains can be appealing, prolonged, unmanaged use may strain the liver, disrupt blood sugar handling, and stress key organs.

For those considering chronically following a ketogenic diet, caution is essential. Regular monitoring, medical supervision, and periodic breaks may help mitigate potential harm. And for many, lower-risk, balanced dietary strategies might offer safer long-term benefits. Ultimately, no diet should be viewed as a "magic bullet", especially when long-term health is on the line.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your doctor for more information. NDTV does not claim responsibility for this information.