Keto controversy? Experts say it’s here to stay

By Dr. Liji Thomas, MDReviewed by Lily Ramsey, LLMMar 18 2025

Experts dispel myths and highlight the science behind low-carb and ketogenic diets for chronic disease management.

Study: Myths and Facts Regarding Low-Carbohydrate Diets. Image Credit: amine chakour/Shutterstock.com

With chronic disease rates rising worldwide, the need for effective lifestyle interventions has become more urgent than ever. Low-carbohydrate ("low-carb") and ketogenic ("keto") diets have gained significant attention—both support and skepticism—among the public and scientific communities.

A recent paper in Nutrients provides an evidence-based expert analysis of the efficacy, safety, and sustainability of these diets.

The need for dietary solutions

Over 90% of American adults either have lifestyle-related risk factors or are undergoing treatment for cardiometabolic diseases such as obesity, diabetes, and heart disease. Identifying effective dietary approaches could play a key role in reducing these risks.

Thousands of clinical trials have shown that carbohydrate restriction can lower the risk of cardiometabolic and mental health conditions. Multiple medical organizations across the U.S., Europe, Canada, and Australia have acknowledged these findings.

Groups like the Obesity Medicine Association and the American Heart Association (AHA) have recognized that low-carb diets may offer greater benefits than simple calorie restriction, particularly for individuals who are overweight or obese. Reported benefits include weight loss, improved blood sugar control, better cholesterol regulation, and reduced blood pressure.

While some healthcare professionals focus on potential drawbacks—such as the "keto flu," a temporary period of fatigue and discomfort—these symptoms are typically mild and manageable. Simple solutions, like increasing electrolyte intake, have been well-documented since 2011.

Other researchers have pointed to studies suggesting an increased risk of mortality with low-carb diets. However, many of these studies involved diets with up to 37% of daily calories from carbohydrates. In contrast, true low-carb diets allow only up to 26% of calories from carbohydrates, while keto diets limit intake to less than 10%.

This latest paper provides a balanced discussion of the benefits and challenges of low-carb and keto diets, drawing on comprehensive research and clinical experience.

Benefits of low-carb diets

Ketosis, a state in which the body burns fat for energy instead of glucose, is a hallmark of the keto diet. Contrary to misconceptions, ketosis is distinct from ketoacidosis, a dangerous condition primarily affecting individuals with type 1 diabetes.

Low-carb diets have been shown to improve most cholesterol markers, with the exception of LDL cholesterol (LDL-C). However, LDL-C increases are typically seen in lean individuals, and current evidence does not strongly link this to a higher risk of heart disease.

One significant study found that a keto diet improved 17 out of 20 cardiovascular risk factors, excluding LDL-C. After two years, participants had a 12% reduction in their 10-year atherosclerotic cardiovascular disease (ASCVD) risk score.

These diets also help normalize blood sugar and insulin levels while reducing inflammation. Notably, several clinical trials suggest that the keto diet can reverse type 2 diabetes, with more than 50% of participants achieving remission within 10 weeks.

One study followed diabetes patients with an average disease duration of eight years and found that blood sugar levels remained normal for two years.

Unlike diabetes medications—such as insulin, sulfonylureas, or thiazolidinediones—the keto diet promotes weight loss, reinforcing its benefits for metabolic health. GLP-1 agonists, while effective for weight loss, carry potential side effects such as pancreatitis.

Additional benefits of the keto diet include symptom relief for conditions like gastroesophageal reflux disease (GERD), irritable bowel syndrome (IBS), and obesity-related thyroid dysfunction. It may also enhance gallbladder function, whereas low-fat diets have been linked to a higher risk of gallstones.

Addressing common concerns

A common misconception is that low-carb diets negatively affect healthy cells or tissues. In reality, the body requires only a small amount of glucose, which can be naturally produced through gluconeogenesis—the conversion of amino acids and fatty acids into glucose.

According to a 2005 report by the National Academies of Sciences, the essential carbohydrate requirement for humans is effectively zero.

Concerns about the consumption of saturated fat and red meat on a keto diet are also frequently raised. However, rigorous reviews of existing evidence show no strong association between saturated fat intake and heart disease. Similarly, red meat consumption has not been conclusively linked to heart disease, cancer, or diabetes.

Higher protein intake does not harm kidney function in healthy individuals. In fact, low-carb diets can be beneficial for diabetes patients with up to stage 3 chronic kidney disease and may even improve kidney function over time.

Low-carb diets consistently lead to greater weight loss compared to low-fat diets and do not cause nutritional deficiencies. They also support high levels of HDL ("good") cholesterol.

Compared to plant-based diets—often followed by individuals already at lower risk—low-carb diets have stronger evidence supporting their effectiveness across diverse populations.

Sustainability and affordability

Adherence is a crucial factor in any diet's success. Studies show that individuals on low-carb diets (fewer than 100g of carbohydrates per day) typically maintain them for at least a year, with over a third continuing beyond two years while sustaining their weight loss.

These diets also promote satiety, helping individuals feel full and reducing cravings, which supports long-term adherence.

From an environmental perspective, the U.S. Environmental Protection Agency reported in 2019 that livestock accounted for only 4% of the country's total greenhouse gas emissions. Additionally, cattle farming has been found to enhance soil health in various ways.

Economically, low-carb diets remain feasible. In 2019, the estimated additional weekly cost per person was only around $9. These diets provide essential vitamins and minerals while supporting physical performance for both athletes and military personnel.

Affordable and nutrient-dense options like eggs and ground beef make low-carb eating accessible. Additionally, free resources are available for those seeking budget-friendly keto meal plans.

Conclusion

Evidence supports the effectiveness of low-carb diets for individuals who choose them. Many common concerns about their health impact are not backed by scientific research. These diets provide all necessary nutrients without adverse effects, making them a viable and sustainable option.

For those looking for an alternative approach to managing weight and metabolic health, low-carb and keto diets offer a well-supported, practical choice.