Ask health and nutrition professionals about their forecasts for diet trends in 2018, and many of them will cite one diet in particular — the keto diet. While the keto (short for ketogenic) diet has been around for nearly a century, its popularity has exploded in the past several years, recently outpacing the Paleo diet for Google search activity.
At least for now, though, the low-carb, high-fat keto diet is more than just a fad, according to some health and nutrition experts. They predict the keto diet will continue to grab attention and headlines — and stir debate — in 2018.
What is the keto diet?
As explained in a 2008 study, the keto diet “is thought to simulate the metabolic effects of starvation by forcing the body to use primarily fat as a fuel source.”
The diet gains its name from ketones. According to the Diabetes Teaching Center at the University of California, San Francisco, production of ketones is the body’s normal response to starvation in someone who doesn’t have diabetes. When our bodies lack glucose (sugar) to provide fuel, we make ketones as an alternative. The liver manufactures ketones as it breaks down fats.
When was the keto diet invented?
In the 1920s, doctors introduced the keto diet as a treatment for epilepsy, according to the U.S. National Library of Medicine. The fasting aspect of the diet helps control epileptic seizures.
The diet was widely used for two decades, but its popularity waned as anti-epilepsy drugs hit the market. Its use surged again in the late 20th century; the diet has been in the nutrition spotlight for the past few years.
Why do people choose the keto diet?
Simply put, some people have dropped weight on the keto diet.
Healthy living advocate Keith Kantor, CEO of the Nutritional Addiction Mitigation Eating and Drinking (NAMED) Program, says that unlike many fad diets that come and go — and that enjoy limited long-term success — the keto diet works.
“It has always been popular among the bodybuilding community for its ability to shed body fat quickly while maintaining optimal amounts of lean muscle,” Kantor says.
What’s behind the success? Kantor says the keto diet targets several underlying causes of weight gain, including hormonal imbalances, and avoids the common restricting-and-binging cycle of some other diets. More than anything, the key is that the diet switches your body from relying on glucose for energy to relying on fat.
“Combining the keto diet with intermittent fasting can provide long-term results without the starvation or suffering,” Kantor says.
What does the research show about the keto diet?
A number of studies have examined the effects of the keto diet. Here’s a sampling:
— A study published in 2004 in the journal Experimental & Clinical Cardiology found that the diet “significantly reduced” the body weight and body mass index of obese patients. In addition, it lowered the patients’ levels of triglycerides (a kind of fat found in our blood), LDL (bad) cholesterol and blood glucose (blood sugar), and raised their levels of HDL (good) cholesterol.
— A study published in 2006 by the American Journal of Clinical Nutrition concluded that a keto diet designed for weight loss “is not warranted,” given the potential harm to a person’s metabolism and emotional state.
— A study appearing in 2017 in the journal Cell Metabolism showed that a keto diet not aimed at fighting obesity improved survival, memory and longevity among aging mice.
— A study appearing in 2017 in the journal Food Science and Human Wellness noted there’s only limited evidence of the effectiveness of the keto diet in fighting Alzheimer’s disease, although “this novel dietary approach” deserves more investigation.
What are the downsides of the keto diet?
While some studies show promise regarding the usefulness of the keto diet, some experts are wary of it.
Registered dietitian nutritionist and licensed dietitian Melissa Groves acknowledges some keto dieters have experienced rapid weight loss, but she cites several drawbacks to the diet as a weight management tool:
- It’s difficult to follow, requiring every gram of food to be measured and weighed on a food scale. Generally, the keto diet calls for 3 or 4 grams of fat for every 1 gram of protein.
- It can trigger major nutrient deficiencies, since it eliminates whole grains completely, and limits the number and variety of fruits and vegetables.
- Its long-term effects have been studied only in children with epilepsy, leaving a question mark hanging over the diet’s impact on others.
Becky Kerkenbush, a clinical dietitian at Watertown Regional Medical Center in Wisconsin, says potential side effects of the keto diet include bad breath, headaches, weakness, fatigue, muscle cramps, low blood sugar, increased cholesterol levels and constipation.
Furthermore, Harvard Medical School points out that the keto diet can be heavy on red meat and other fatty, processed and salty foods—all of which are unhealthy.
“Instead of engaging in the next popular diet that would last only a few weeks to months (for most people that includes a ketogenic diet), try to embrace change that is sustainable over the long term,” the medical school advises. “A balanced, unprocessed diet, rich in very colorful fruits and vegetables, lean meats, fish, whole grains, nuts, seeds, olive oil, and lots of water seems to have the best evidence for a long, healthier, vibrant life.”
In summary, Chelsey Amer, a registered and certified dietitian nutritionist who’s the creator of CitNutritionally.com, says that like any diet that eliminates entire food groups, the keto diet “can be extremely dangerous for your health if done on a whim and not with a trained professional.”