The Best (and Worst) Nutrition Advice of 2019

This was a weird year for food. Scientists grew (surprisingly good) plant-based meat products in labs, some people decided to eat nothing but meat, other people barely ate anything at all. Seltzer had a comeback, researchers developed wearable tech that could tell you when you needed to hydrate, and an Outside editor experimented with drinking an entire gallon of water a day. Amid the madness, a few ideas drifted to the top, ones that were evidence based and reasonable and could actually help you live a little more healthfully. Read on to learn which trends you should forget about in the new year and the few that you should carry with you.

Skip: Celery Juice 

In May, wellness guru Anthony William published a book claiming that daily celery juice could detox your body and provide all kinds of dubious health benefits, like flushing toxins from your brain and curing asthma, addiction, and Lyme disease. It caught on in certain circles, but none of his claims were backed by scientific evidence.

“The idea that we need to detox our body with a product or certain food is really unfounded,” says Brenna O’Malley, a registered dietitian. Your entire digestive system breaks down the food you eat, and your liver works as a detoxifier by filtering out any unwanted substances. “We don’t have much, if any, research to support the claims that celery juice is miraculous or a detoxifier,” O’Malley says. Your body breaks down celery juice, just like it does any other vegetable juice.” While drinking celery juice won’t do any harm, it likely won’t do any good either. The closest thing to an endorsement of the stuff is a 2013 trial during which 30 adults with high blood pressure took celery-extract supplements (pills, not juice) for six weeks and reported slightly lower blood pressure at the end of the trial. Caveats? The extract was far more concentrated than juice, there was no control group, and the lead researchers worked for the company that made the celery extract. 

Keep: Fermented Foods for Gut Health

The gut microbiome is a relatively new area of study, but there’s promising evidence that the unique makeup of healthy bacteria that exists in each of our bodies is a key factor in overall health. A 2019 review found that ingesting both probiotics (bacteria) and prebiotics (a type of dietary fiber that feeds bacteria) can support a healthy microbiome.

But getting probiotics and prebiotics in supplement form probably isn’t your best bet. “Currently, there’s no evidence that long-term, continued consumption of supplemental probiotics maintains wellness,” said Jack Gilbert, a researcher at the University of Chicago, in a previous interview. Instead, it’s best to get probiotics through fermented foods. Prebiotics, on the other hand, can be found in fruits, vegetables, beans, and other high-fiber foods.

Skip: Extreme Intermittent Fasting

Intermittent fasting (IF) is a time-restricted diet during which you only eat for a set period of time each day. It’s more of an umbrella term than a rigid protocol: one popular approach is to eat during an eight-hour window each day; another is to eat normally except for one or two days of extremely low-calorie intake per week. But this year, the more extreme one-meal-a-day (OMAD) approach gained some traction. Experts warn against OMAD for a variety of reasons. One small 2007 randomized control trial of 21 adults over eight weeks found that eating one meal a day resulted in lower body-fat percentage but higher hunger levels, blood pressure, and cholesterol levels compared to subjects who ate three meals a day. And that doesn’t take into account the emotional and social toll of such an extreme diet.

The benefits of any kind of IF are still up in the air, but if you’re curious about it, stick to a gentler approach. Eating within a 12-hour window—from 8 A.M. to 8 P.M., for example—will likely deliver many of the same potential benefits, nutrition scientist Stacy Sims previously told Outside. 

Keep: Intuitive Eating

Intuitive eating has been around since 1995, when registered dietitians Elyse Reich and Evelyn Tribole published a popular book on the topic. But it gained mainstream traction this year: we wrote about it in May, The New York Times published an op-ed in June presenting it as an antidote to toxic wellness culture, and dozens of nutritionists encouraged their clients (online and off) to start eating a little more freely. 

This relaxed approach to food is guided by ten principles, like “honor your health,” “respect your body,” and “challenge the food police,” and it’s all about tuning in to your own preferences and needs and tuning out messages about what you should or shouldn’t eat. While more research is needed, there’s evidence that intuitive eating is good for both mental and physical health, and it might even be associated with a more nutritious diet overall.

Skip: Keto 

Going keto means getting 75 to 80 percent of your calories from fat, 15 to 20 percent from protein, and less than 5 percent from carbs. It’s also one of the most popular extreme diets out there at the moment. There is significant evidence that ketosis—a metabolic state wherein the body starts using fat as a primary fuel source due to a lack of carbs—helps reduce seizures in people with epilepsy. But there aren’t many evidence-backed benefits beyond that. 

Amy Gorin, a registered dietitian in the New York City area, explained that while short-term weight loss often happens on the keto diet, it generally isn’t sustainable. Maintaining ketosis is difficult, since going over your carb allotment just once can trigger your body to start using glucose (carbs) as fuel again instead of fat. And many people gain back any weight they lost once they begin to eat regularly, Gorin said. Low-carb diets aren’t an inherently better choice than any other calorie-restricted diet, but if you think they might be right for you, Gorin suggests a more moderate approach than keto. 

Keep: Plant-Based Eating

Plant-based burgers blew up this year. You can now get an Impossible Whopper at Burger King or an Impossible Slider from White Castle, both engineered to look, cook, and taste like meat. If that isn’t proof enough that plant-based foods are here to stay, consider the fact that, according to one report, the global plant-based “meat” market was valued at $10 billion in 2018 and is forecasted to hit $31 billion by 2026. 

These new plant-based meats aren’t intended to be a healthier version of beef—the nutritional profile is actually quite similar; instead, they’re meant to be a more environmentally friendly way to eat what tastes like meat, explained Jonathan Valdez, a registered dietitian in New York. 

The research on the health benefits of limiting your consumption of animal products is still evolving, but it’s promising. A 2019 review of several randomized control trials found that vegan and vegetarian diets are linked to improved metabolic health. You don’t have to go full-on vegetarian, according to Shivam Joshi, an internal-medicine physician at the New York University School of Medicine. Even swapping out a handful of animal-based meals every week will benefit you. 

Skip: Adaptogens

Using plants for healing purposes is an ancient practice, but Western wellness culture really dug its teeth into the idea this year. Adaptogens, defined by scientists as plant-based substances thought to enhance the body’s resistance to various kinds of physical and mental stress, are showing up all over: keep an eye out for ashwagandha on your popcorn or maca in your smoothie bowl. 

Any wellness claims that brands make about these ingredients are hopeful guesses at best. Ashwagandha’s many purported benefits (pain relief, diabetes management, and anti-aging, among others) have yet to be consistently proven by research. And although some people believe that maca can improve reproductive health and fight cancer, these claims also have no real evidence behind them. That said, adaptogens are unlikely to hurt you, so if you don’t mind the taste (or the cost), keep on eating them. But don’t claim that they’re magic.

Keep: Seaweed

Sushi has been popular for years, and crispy seaweed snacks are available everywhere from Whole Foods to Trader Joe’s. Still, most of us don’t yet think of seaweed as a comparable alternative to green vegetables like kale and spinach. An April New York Times article explained that seaweed is a much lower-impact crop, since it doesn’t use any land, fresh water, or fertilizers. In fact, it can even help the environment: kelp has been shown to drastically improve water quality. Like other green vegetables, seaweed is packed with micronutrients, but it’s not your typical green. The rich umami flavor can add depth to many dishes.