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We’re not sure yet, but new research suggests that the keto diet could be more beneficial for our health than previously realized.

Carolyn Williams, PhD, RD
January 31, 2018

The ketogenic diet, or keto diet, has been around for almost 100 years. While this low-carb, high-fat diet has had occasional resurgences in popularity over that period, new research is causing former naysayers to now give it a second look.

The keto diet has sparked controversy among dieters and nutritionists for its reputation as a low-carb fad diet. However, new research suggests that it may in fact be a legitimate healthy eating plan. 

Regardless of what side you take, the keto diet is a hot topic. In fact, five of the current top twenty titles on Amazon’s list of best-selling diet books contain “keto” in the title. Let’s take a closer look at what the keto diet actually means, how it’s different from the Atkins diet, and what new research tells us about the potential health benefits of this eating plan.

What is the Keto Diet?

The ketogenic diet is a low-carb, high-fat eating plan, and while there are some diet variations, this typically means a calorie breakdown of 5-10% carbohydrates, 70-80% fat, and 15-25% protein. (For a quick comparison, current health recommendations are 45-65% carbs, 20-35% fat, 15-25% protein.) This equates to an intake of 20 to 50g carbohydrates per day though some keto devotees aim to stay below 20 grams.  

RELATED: Here’s What a Day of Eating on the Keto Diet Actually Looks Like

The goal of this very low carb intake is to put the body in a state of ketosis, a situation where the body is forced to rely on "ketone bodies" (molecules produced when fat breaks down) for fuel. Ketosis occurs when the body is deprived of adequate carbohydrates, and this triggers the body to break down fat stores and release fatty acids into the blood. The liver converts fragments of the fatty acids into ketone bodies which are broken down to provide the body energy to survive.

Ketosis isn’t a natural state that the body is used to being in, and many keto diet followers report side effects, primarily the first week. This is sometimes described as “keto flu” and often involves headaches, fatigue, and overall malaise.

Keto Diet vs Atkins Diet

Both the Atkins diet and the keto diet are considered low-carb plans, but they have several key differences. Unlike the Atkins diet, the keto diet doesn’t emphasize significantly increasing protein to make up the carbs not being consumed. Instead, the keto diet makes up those calories by primarily increasing fat intake. The moderate protein intake of the keto diet alleviates strain that low-carb diets such as Atkins can put on the kidneys. However, the long-term effect of high fat consumption have long concerned health professionals.

Is the Keto Diet Healthy?

The ketogenic diet was developed in the 1920’s as a treatment for epilepsy, and it can be life-changing for those patients. Triggering the body to use ketone bodies for fuel appears to influence neurotransmitter activity and neuron functioning, which can significantly reduce seizure episodes for many people with epilepsy. In fact, the ketogenic diet is still routinely prescribed as a treatment.

But outside of epilepsy treatment, many professionals have avoided recommendations for the keto diet. Health professionals (myself included) are still unsure of the long-term effects of a high-fat, low-carb diet, and the dubious claims made by proponents have caused many to roll their eyes.

RELATED: The Best Advice (and Worst Mistakes) for Going Low Carb

But recently, groundbreaking research from legitimate sources suggest there is merit to the claim that regularly putting the body in ketosis may aid weight loss, prevent type 2 diabetes, reduce the risk of metabolic syndrome and cardiovascular diseases, and even (yes) slow or stop cancer growth, or preserve brain health and neuron functioning. Our knowledge is still very limited so it is difficult to confidently recommend the eating plan, but here’s what research is suggesting.

Effects on Weight Loss

While reducing calories is still a key component to any weight-loss plan, the macronutrient breakdown makes a difference. When Brigham Young and Harvard researchers conducted a meta-analysis in 2015 analyzing 53 weight loss studies that included more than 68,000 participants, they found that lower-carb, higher-fat diets lead to slightly greater weight loss and significantly greater long-term loss when compared to low-fat diets.

Effects on Insulin Resistance and Diabetes

As type 2 diagnosis and pre-diabetes rates continue to skyrocket, it appears that the standard dietary protocol of counting carbs and choosing healthier foods is no longer working.

RELATED: Why Trying to Avoid Certain Unhealthy Ingredients May Not Work

A group of 26 doctor and researchers from major universities and medical institutions agrees. They published a critical review of the current research in 2015 in Nutrition suggesting that carbohydrate restriction should be the primary focus of diabetes prevention and management. In fact, they cited studies suggesting the biggest improvements in glycemic control and insulin usage happened in the most carb-restricted group (20% carbs), allowing many to reduce or quit medications.

Heart Disease

If you find yourself wondering how high fat intakes, even if predominantly from healthy sources, can be good, you’re not alone. This is probably the biggest debate among health practitioners partly because the results to date are mixed and partly because we don’t have much long-term data. However, the 2015 Nutrition article also suggests that intake of fat and saturated fat do not increase cardiovascular risk. Additionally, a 2013 review of literature in the European Journal of Clinical Nutrition offers compelling data—eating less than 50g carbs daily may improve cholesterol numbers even with the increased fat consumption.

Cancer

The initiation and growth of cancer cells is complex and an area of limited knowledge. However, long-term inflammation in the body, as well as high levels of glucose and insulin, appear to play a role in cancer development. Although primarily suggested from studies of rats, limiting carb intake to less than 50g daily may essentially starve cancer cells of glucose. This may possibly cause cancer cell death or growth inhibition, based on the 2013 European Journal of Clinical Nutrition review.

Dementia, Alzheimer’s and Parkinson’s Diseases

Brain deterioration and diseases all have different etiologies, but we may be able to use low-carb, higher-fat diets like the keto diet as a way treat or reduce risks. As demonstrated in patients with epilepsy, ketone bodies can influence neurotransmitter activity and neuron integrity. This is a newer area of research with limited studies, and so far the results are vague but promising.

So, What's the Verdict on the Keto Diet?

The simple answer is we’re not sure, and a definitive answer won’t come until there’s a lot more research. While findings suggest that following a low-carb, high-fat diet may have potential benefits for some individuals, there’s still a lot of unknowns. The biggest questions include what an optimal carb and fat breakdown is for ketosis and health, which individuals may benefit the most, the ideal dietary fat makeup, and long-term health effects.

The keto diet isn’t for everyone, since trade-offs include cutting out less healthy carbs, along with fruits, starchy vegetables, and beans. Highly active individuals may perform more poorly on it, and individuals who are pregnant or have kidney issues should definitely avoid it.