In 2018, Americans turned to Google in droves to seek out information on high-profile diets—and while some of the most-searched diets are backed by solid scientific evidence, many others are ill-researched and potentially even dangerous, according to Keri Gans, a registered dietician and nutritionist writing for U.S. News & World Report.
"In the past, I have been disappointed in what diets appeared popular, and this year proves to be no different," Gans writes. "I hold out hope that most of these diets were merely searched—not actually tried."
Here are the 10 most-searched diets—and what research has to say about their potential risks and benefits.
The 10 most-Googled diets
1. Keto Diet
The keto diet, which ranked No. 6 among the most-searched diets of 2017, nabbed the top spot in 2018. The diet seeks to promote weight loss by decreasing a person's carb intake to the point that it sends the body into "ketosis," a state in which the body breaks down ingested and stored body fat into ketones that are used as energy.
But while the diet is high in fat and recommends an adequate protein intake, it remains "controversial" among the scientific community, Gans writes. "[P]utting your body into a ketogenic state … is not something you should take lightly," Gans explains. She notes that potential side effects include fatigue, increased urination, vomiting, and confusion.
2. Dubrow Diet
The Dubrow diet was popularized by reality-TV couple Terry Dubrow, a plastic surgeon for the show "Botched," and Heather Dubrow, who appears on "The Real Housewives of Orange County." Although it includes some complicated rules for dieters, its core is intermittent fasting—an approach that, Gans writes, has not yet been proven to be effective for sustaining weight-loss long-term.
3. Noom Diet
Noom is a smartphone-based app that offers personalized weight-loss coaching through two 16-week programs, one for weight loss and one diabetes prevention. The programs promote lifestyle interventions to achieve weight-loss goals.
According to Noom, users on average lose 18 pounds in 16 weeks, which is a "healthy weight-loss rate," according to Gans. However, while she says she "can't argue with what appears to be a rational approach to weight loss," Gans notes that an app-based weight loss program might not be effective for everyone.
4. Carnivore diet
This diet—you guessed it—consists entirely of meat. That raises alarm bells for Gans, who notes that "years and years of scientific research" show that humans need vegetables and fruits to get the antioxidants, vitamins, and minerals that help prevent illnesses such as cancer, heart disease, and stroke.
5. Mediterranean Diet
The Mediterranean diet was ranked No. 1 on the U.S. News list of Best Overall diets for 2019. The diet was originally inspired by the observation that people in the Mediterranean live longer, healthier lives by having diets that are low in sugar, red meat, and saturated fats, but high in vegetables, nuts, and fruits.
Research shows that there is "conclusive scientific evidence" that the diet lowers the risk of heart disease and increases longevity, Gans writes. Still, she notes, "since a diet usually conjures up thoughts of something you eventually go off, this diet really should just be called 'healthy eating.'"
6. Optavia Diet
Optavia is a branded line of food products and coaching support that aims to help consumers follow one of three distinct diet plans. The plans advise eating both "lean and green meals," which are homemade meals of meats, vegetables, and healthy fats; and "fuelings," which are packaged foods made by Optavia.
The diet restricts calorie intake to around 800 and 1,000 calories per day—far below the level required to maintain weight, and below the recommended levels that many doctors recommend for weight loss. Gans said that while dieters might well lose weight on the Optavia diet, that's because they are "basically ... starving."
7. Dr. Gundry Diet
This diet was created by Dr. Steven Gundry, an author and physician, and encourages dieters to avoid substances called "lectins," which defend plants from being eaten by insects and animals. When ingested, lectins bind to carbohydrates, which can supposedly cause inflammation and other adverse reactions.
While some research supports the presence of a negative relationships between lectins and autoimmune diseases, Gans said there is not enough evidence to warrant Gundry's recommendation that dieters avoid entire food groups that contain lectins.
8. Fasting Diet
A fasting diet simply involves not eating food for a period of time. While there is some research that intermittent fasting can promote weight loss, the studies are not conclusive, Gans writes. As such, she would approach "any type of fast with a little skepticism, especially if your goal is long-term weight loss."
9. Low-FODMAP Diet
The point of this diet is to significantly reduce the presence of or remove certain carbohydrates, called FODMAPs, from the diet. FODMAPs is an acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, which can cause gastrointestinal issues, especially for people with irritable bowel syndrome.
The diet is solidly grounded in scientific evidence for individuals suffering from irritable bowel syndrome. However, Gans writes, if you aren't sensitive to foods that contain FODMAPs, "there is absolutely no reason to start this diet."
10. Shepherd's Diet
The shepherd's diet, Gans writes, "appears to be based on guidance from the Bible" and identifies so-called "healing fats" and "holy fats" in the diet that can, supposedly, help people burn fat. But Gans writes that "there is absolutely no scientific data" available to support the diet's supposed benefits (Gans, U.S. News, 1/15).
How providers can address nutrition and food insecurity
One in six households experience food insecurity, which means they have limited or uncertain access to nutritionally adequate and safe food. Individuals who are food insecure are two times as likely to suffer from diabetes and are three times as likely to have poor overall health status.
Recognizing the link between food insecurity, chronic illness, and poverty, several hospitals have launched innovative programs designed to facilitate patients' access to healthy, affordable food.