Beware the fad diets! The New Year will be here before you know it, and perhaps you’re already forming a mental list of everything you want to change or accomplish in 2020. For lots of people, fad diets are items on that list disguised as eating healthier—71 percent of people, actually, according to a survey Inc. took of 2,000 people in 2018. But here’s the thing: Many people tend to confuse “healthy eating” with “dieting.” But fad diets often aren’t sustainable—especially if you’re a cyclist who’s ready to tackle some big rides or podiums in 2020. Eating healthy, balanced meals on the regular requires a shift in mindset since it’s a longterm habit you want to establish.

Diets, however, tend to end after a few months, and then you find yourself shoveling all the pizza you weren’t “allowed” to eat into your mouth in one night. If you’re an endurance athlete pushing for your best performance possible, then trendy diets such as keto or Whole30 aren’t on our recommendation lists. We talked to a couple of experts, and we all agree: It’s time to let go of these diet fads, once and for all. (It’s worth noting that if any of the following diets do work for you, you don’t need to stop cold-turkey—different things work for different people. Consult your doctor to make sure you’re properly taking care of your body’s needs, avoiding food allergies, etc.) Here is the list of the five fad diets you should ditch in 2020.

Fad 1) Paleo

A little refresher for you: The goal of the paleo diet is to revert back to the way our ancestors ate: “hunter-gatherer style.” This means you’re focusing on meats, vegetables, and nuts, and avoiding grains, legumes, and dairy. A big win for paleo is that it forces people to eat whole foods rather than processed junk. But if you’re on a long ride or pushing your limit at the end of a race, your bag of almonds or carrots is only going to get you so far.

READ MORE The 10-Step No-Diet Weight-Loss Plan

Fad diets aren’t always good for endurance sport. Here’s a fact we’ll continue to bring up as we go through this list: Athletes need carbohydrates for fast fuel. When you neglect grains, you neglect a huge source of carbs your body can use before and after your workouts.“[Grains] get a bad reputation because there are some that are processed and very high in carbs, like white grains, white bread, things like that,” said Natalie Rizzo, M.S., R.D., New York City-based dietitian and owner of Nutrition a la Natalie. “But there are a lot of whole grains out there, such as brown rice and quinoa, that are sources of carbs, and a good source of fiber. There’s no reason [athletes] should stay away.”

“Fiber” is another trigger word that people might be wary of, but it’s important for any diet because it helps keep your digestive system regular. Who wants to feel constipated and bloated when you’re out in the middle of nowhere on your bike for hours on end? You can avoid fiber before a big ride or race, but otherwise, it should be present in a healthy diet. Grains are good for your heart, too, and if you eat enough, studies show they help lower your cholesterol levels.

The Verdict: Paleo is a great base for a healthy diet, especially if you struggle with eating too many processed foods and need to eat more whole foods. But when it comes to cyclists putting in long hours and lots of miles, you need a balance of simple and complex carbs to give you energy and fiber to give you a healthy gut.

Fad 2) Keto

Of the fad diets trending this year,  you’ve most probably heard of this one. A typical keto diet consists of roughly 60 to 80 percent fat, 20 to 25 percent protein, and 5 to 10 percent carbs. By consuming such a high intake of fats, you’re trying to induce ketosis, which is when your body has gone through its source of carbs and starts burning fat instead. Your body produces ketones and uses them as sources of energy for your brain and central nervous system.

A couple of pros to this diet are the high percentage of protein and, like paleo, the concentration on whole foods. The cons are the high percentage of fat and an insufficient amount of carbs. There’s a reason why many endurance athletes lean on simple sugars, such as gummies or GUs, during long rides—they provide energy in the form of carbs that break down quickly. Fats, on the other hand, take a lot longer to digest.

“It’s very inefficient,” Rizzo says. “It takes a lot more work for the body to break down fat and use it as fuel. You’re almost putting more work on your body than you need to because you’re just not storing as many carbs in the muscle and the liver, which is known as glycogen.”

The lack of carbs in the keto diet also forces you to cut back on fruits and vegetables, which are full of naturally-occurring carbs. This means you’re depriving your body of nutrients it needs.

Generally speaking, you’re not getting a lot of vitamins, minerals, fiber, or antioxidants, Rizzo says. “That can lead to deficiencies in basic nutrients such as vitamin C or A—things that should be part of any person’s diet.”

READ MORE The Truth About Carbs

These are nutrients you not only need for your everyday life, but also fuel you need in training—especially for the last leg of a ride or race when you need to finish strong. In those anaerobic exercises, your body can’t actually burn fat because oxygen has to be present in order to do that. Therefore, fat can’t give you proper fuel to help propel you across the finish line as fast as you want during a hard and fast effort.

“For people who might be trying to get faster or PR in a race, it’s going to be a rough day for you, because your body was running on a fuel source that it wasn’t really designed to,” says Amy Goodson, M.S., R.D., C.S.S.D., a dietitian in the Dallas-Fort Worth area.

If you’re already fat-adapted and prefer to simply ride your bike at a mellow, steady-state for yours, then a keto diet might work well for you. But if you plan on any HIIT workouts, charging up hills during rides, or sprinting for town lines or finish lines, then you want to avoid.

The Verdict: If you’ve got big goals for the bike in 2020, then keto is not for you—you just won’t make it. The diet lacks carbs and fiber, thus depriving you of the required nutrients, energy, and mental sharpness you need to ride your best.

Fad 3) Whole30

This popular elimination diet was created in 2009 to focus on eating whole foods and avoid a whole host of items—such as sugar, grains, legumes, dairy, and alcohol—for 30 days. There’s no doubt that this diet has helped a lot of people reevaluate their nutrition choices, but is it actually effective for athletes? Goodson and Rizzo agree that the Whole30’s restriction is hard to follow, whether you’re an athlete or not.

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Admittedly, Whole30 is not intended to be followed for more than 30 days, but Goodson says, “If you can’t do [a diet] for the long haul, that should be a good sign that it may not be the best option.” Unsustainability is a hallmark of fad diets. When it comes to your workouts, eating very few carbs (which becomes glycogen) on the Whole30 diet can reduce your body’s ability to handle high-intensity interval training (HIIT) and sprinting on the bike. You need glycogen—something Whole30 is missing—to fuel those high-intensity training days or else you’ll bonk. Hard.

The Verdict: “[The Whole30] is just hard for seasoned athletes because they need more nutrients than the average person,” Rizzo says. Case in point: If you want to try the Whole30 to see what all the fuss is about, go for it. It can help you learn to make better nutrition decisions down the line. Just know you probably won’t be at your peak performance during that month and will have to take it easy during your workouts.

Fad 4) Gluten-Free

First off, if you have an allergy or intolerance to gluten or you have celiac disease, you can skip this section. Gluten is not for you, and that’s okay! There are foods you can eat that provide the whole grains you need, such as brown rice, quinoa, and amaranth.

But for everyone else who’s reading this, I’ve got three words for you: Embrace the gluten.

Here’s why: When you cut out gluten without a medical need to do so, you also cut out a huge source of fiber, vitamin B, iron, copper, and magnesium, to name a few, all of which help you fight fatigue.

“There’s been a significant amount of research that talks about whole grains that are a part of a healthy diet and contributing to making or maintaining a healthy weight,” Goodson says. “Fiber slows down digestion and helps you stay full longer.”

The Verdict: Unless you have celiac disease or an intolerance to gluten, there’s no real need to avoid it. In fact, if you’re missing out on gluten, you might be missing out on your best performance on the bike.

Fad 5) Fat-Free

We know, it’s not the ’90s anymore—the “fat” scare has definitely waned over the past few decades. And we’ll sing one praise of the keto diet: It helped bring fat back – score one for the fad diets.

But even with the growing popularity of avocados, nuts, oils, and other healthy fats, there are still people out there who are terrified of any mention of “fat” anywhere on any label. And picking “full fat” options? Forget it!

Let’s set the record straight and remember why we athletes need fats in our diet. Healthy fats—meaning higher in mono and polyunsaturated fats and lower in saturated fats—help your body absorb vitamins such as vitamins C, D, and K. Omega 3 fatty acids—such as salmon and walnuts—help decrease inflammation, increase good cholesterol (HDL), and lower the risk of heart disease.

“There have been correlation studies showing that people who eat more healthy fat in their diet, like walnuts and avocados, have better brain health and better heart health,” Rizzo says. “They have lower cholesterol levels and have better cognition. So fat is a healthy nutrient for the brain, which is helpful for athletes because that’s part of the sport—the mental capacity.”

The Verdict: Incorporating healthy fats in your diet decreases inflammation, keeps your heart healthy, and keeps you fuller longer—all great for your general health and performance on the bike.

Fad 6) Bonus: The Nut Butter War

This clearly misses the “fad diets” label, but it’s a myth we’re going to bust right here, right now. Your R300 fancy cashew or almond butter is not healthier than a R30 jar of natural peanut butter.

Now, should you avoid nut butters that have a lot of added sugar and other weird ingredients you can’t pronounce? Yes—and that goes for most things you eat. But if you’re comparing nut to nut, you will find slightly different properties, but that does not make one superior to the other.

So where did this misconception come from? Goodson argues it has to do with the rise of the paleo diet. “A peanut is a legume, and the paleo world doesn’t like legumes for whatever reason,” she says.

READ MORE 5 Ways You’ve Never Tried Eating Peanut Butter

Earlier this year, we broke down the nutrients of peanut butter and almond butter for comparison, and they were neck-in-neck for their amount of unsaturated fats (the good kind), fiber, and protein. Almonds are slightly higher in vitamin E (which helps protect your immune system), but not enough to say they are better for you than peanuts. The biggest difference: Almonds and almond butter are way more expensive.

The Verdict: Eat whatever kind of nut butter you want—just make sure you’re still reading labels to watch out for added sugars. Stick with the purely nut-based butters and, as always, watch your portion control. Some almond or peanut butter toast after a workout is a great recovery snack, but eating a whole jar in one sitting may not go over well. All together now: Everything in moderation.

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