The Atkins diet, the grapefruit diet, keto, paleo, Whole 30—do any of these sound familiar? They’re all trendy diets that have come and gone over the years, often promising quick results for anyone willing to follow a restrictive (and often unsustainable) eating plan. While losing a lot of weight quickly sounds appealing, these diets often leave people less healthy than they were before and gaining the weight back as soon as they go back to their normal eating.
It raises an important question: If trendy diets (sometimes referred to as fad diets) don’t make us healthier, why do they have so much appeal?
Trendy diets—like all trends—come and go
The big problem with losing weight through good nutrition is that it can be a slow process, as Debbie Petitpain, MBA, RDN, spokesperson for the Academy of Nutrition and Dietetics, explains. Making gradual changes to incorporate more vegetables, fruits, and whole grains, while reducing calories by just enough to keep you going steady, could help you lose about 1 or 2 pounds per week. That kind of weight loss is healthy and sustainable, but it’s not as appealing as the thought of a trendy diet that promises dramatic results very quickly.
Plus, trendy diets are like other trends—they’re exciting! “People are naturally drawn to new and novel ideas,” Petitpain explains. “Diet trends often come packaged with fresh, catchy names, unique rules, or celebrity endorsements, making them seem more exciting than traditional, evidence-based dietary advice. It’s human nature to get bored with the same advice to ‘eat more vegetables and exercise regularly,’ so trendy diets seem like a new, intriguing option.”
Petitpain offers a great rule of thumb for determining what kinds of eating habits are best to adopt: “If you wouldn’t want to follow it for life, it’s probably not the best approach for long-term health,” she says. In other words, a diet that excludes your favorite foods could help you lose weight, but if you can’t eat that way forever, you won’t maintain those results forever either.
Dr. Taylor Wallace, CEO of Think Healthy Group and a member of the American Society for Nutrition, echoes this idea by pointing out that anything promising an easy solution is usually too good to be true. Some fad diets might make practical sense (as an example, he points to paleo, which encourages people to “eat like our ancestors”) but they lack scientific research to support their promises.
“Most of these diets are unhealthy because they typically eliminate or restrict certain food groups that provide a unique set of nutrients that are important for long-term health,” he says. “We also know that generally people can’t maintain most diets in the long term—especially the restrictive ones.”
Don’t fall for it
The biggest risk of a fad diet is that it’s too restrictive to provide everything we need for a healthy lifestyle. For example, keto might make it easy to eat fewer calories, but because keto does not allow any whole grains or many fruits and vegetables, you could end up deficient for many vitamins and minerals. When you’re malnourished like this, you’re likely to feel fatigued or tired, or you could be at increased risk of getting sick.
There are also long-term risks to nutrient deficiencies. Wallace explains that a diet low in dairy could mean someone is missing out on enough calcium, which leads to suboptimal bone health and osteoporosis over time. “I think the long-term issues are increased weight gain and inadequate nutrient intakes that could promote suboptimal health and, in some cases, chronic disease,” he says.
And for the many people who are turning to fad diets to lose weight, these restrictive eating patterns could ultimately have the opposite effect in the long term. “Repeatedly trying restrictive diets can slow down your metabolism, making it harder to maintain a healthy weight over time,” Petitpain says. “It can also lead to disordered eating patterns and an unhealthy relationship with food, as well as increase the risk for chronic diseases like heart disease and osteoporosis due to poor nutrition.”
Is there any good with the bad?
Just because a way of eating is trendy doesn’t mean that it’s necessarily unhealthy. If you enjoy eating a certain way and can get all the nutrients you need, you can find a way to make it work. “I’m sure some diets work for some people,” Wallace says. “I think as long as you’re eating a variety of foods and food groups and not doing anything crazy, like people addicted to eating couch foam on TV, then I think it’s OK to play around and figure out what works best for you.”
Trendy diets are often about taking healthy concepts and applying them to the extreme. For example, a low-carb diet could encourage you to cut back on sugar or refined white flour—but if you cut out too many whole grains and starchy vegetables, you might not be getting enough fiber.
It’s important not to take it to an extreme. “The key is to look for evidence-based advice that aligns with long-standing nutritional guidelines, like eating more whole foods and prioritizing balance,” Petitpain says. “If the diet feels overly complicated, too restrictive, or sounds too good to be true, that’s when it’s time to be skeptical.”
How to spot a fad diet
The next time a friend tells you about the great new way of eating they’re trying out, you might want to pause and assess. Not all trendy diets have names, but most of them have similar qualities that should be red flags. Signs of a fad diet include:
- If it promises rapid results, be wary. Remember that it’s better to be slow and sustainable. Weight that is lost quickly can be gained back quickly, especially if you go back to your normal eating habits.
- If it cuts out entire food groups or sets rigid rules, it’s probably too strict to be practical. “If you hear, ‘No carbs allowed!’ or ‘Only eat between certain hours,’ that’s a warning sign,” Petitpain says. “Healthy eating should be about balance and flexibility, not restriction and deprivation.”
- Look at who is promoting it. Petitpain encourages taking nutrition advice from health experts whose guidance is backed by scientific research—not from influencers or celebrities making bold claims.
