The Whole30 diet is about as polarizing as pineapple on pizza (… sorry to bring up pizza if you’re currently Whole30-ing). I’ve done the diet twice, and people’s reactions range from “Good for you!” to “That’s stupid, why would you ever do that?” Many people swear by Whole30 as a way to reset their bodies and repair their relationship with food, which sounds amazing, right? But as with anything that seems magical, there’s a catch.

First, a quick refresher on what Whole30 is: For 30 days, you eat only vegetables, eggs, meat, seafood, fruit, and healthy fats. No grains, no dairy, and certainly no sugar allowed. This is a premise that seems simple in theory, if not always in execution—giving up croissants and wine (oh, the wine) can be a real bummer.

As if giving up booze, bread, and cookies for a month isn’t enough of a downer, for the first two weeks, there’s a good chance you’ll feel fatigued, headache-y, and generally like the line-face emoji—I learned firsthand that this emotional state is not exactly conducive to a good sweat session.

Again, it’s not all bad—I’ve done this thing twice for a reason. Reported perks after those questionable first two weeks include better energy levels, clearer skin, improved sleep, and of course, weight loss.

So why do you feel so ick in the first couple of weeks, anyway?

“When you take away gluten and refined carbs (a.k.a. sugar), it will affect your body until it adjusts,” explains Astrid Swan, NASM certified trainer and Barry’s Bootcamp instructor. Carbs like sweet potatoes and regular potatoes are allowed on Whole30, but grains are not. Your body has to adjust to the lack of these common ingredients in your diet, especially sugar—which often means your energy levels take a nosedive.

Another reason for Whole30 fatigue is that most people are severely restricting their calories on this diet. “When you cut your energy source, you’ll feel tired,” says clinical exercise specialist Charlie Seltzer, M.D.

But I didn’t want to give up working out when I did Whole30, so instead, I looked for ways to optimize my workout routine for the “blah” phase of my Whole30 experience. I went to the experts for help and was told the following (by pretty much everyone): When you embark on Whole30, you’re already making a drastic change to your lifestyle, so don’t make big changes in your workout routine. For instance, if you predominately do yoga, the first couple of weeks of Whole30 probably isn’t the best time to sign up for your very first CrossFit class. With that in mind, here’s how to adjust your current workout routine to fit in with your Whole30.

If you love yoga:

Swan says yoga is great when you’re doing a Whole30 because it focuses on breath, core, form, and mental game. “So much of Whole30 is mental,” she adds, “and yoga can help you find your balance—it’s a lower intensity workout that won’t drain you.” Also, yoga can increase your serotonin levels—a.k.a. one of the happiness hormones—and trust me, extra serotonin will come in handy those first couple of weeks without bread.

If you love CrossFit:

Stop doing CrossFit on Whole30 because it’s too intense? Annie Thorisdottir would never. I won’t suggest you skip CrossFit for two weeks while you’re Whole30-fatigued, because a) I’m not a monster and b) as a fellow CrossFitter, I know you probably wouldn’t heed that advice.

So here’s the good news: Even if you feel tired and sluggish, you can still keep up your CrossFit routine. The key is being OK with scaling the movements to accommodate your lower energy levels.

“I would suggest people understand that they probably aren’t going to PR their Fran or Grace when following Whole30 because they will be calorie- and carb-deficient,” says certified Level 1 CrossFit trainer Julie Upton, MS, RD. “They should just set their CrossFit fitness goals aside for the month or so and focus on getting leaner on Whole30.” You may not Rx every workout, and that’s OK.

If you love Pilates:

“The key principles of Pilates are concentration, centering, precision and control,” says Anastasiya Goers, a Pilates instructor who has survived—er—done Whole30. “During the workout, you learn to pay attention to your body and work with it, not against it,” she says. It’s these qualities that make it a good complement to Whole30. Plus, a lot of the moves in Pilates are done while you’re lying down. #Winning.

If you love running:

Reality check: Don’t expect to beat your mile time in the first couple of weeks of Whole30. Your body is still going to be adjusting to the new way you’re giving it fuel—and pushing yourself when you’re fatigued could lead to injury or further exhaustion.

“It’s fine if you only log four miles instead of five,” Seltzer says. “If you push yourself and end up tearing your Achilles tendon, then you’re going to be out for months.” We’re guessing you don’t want that, so scale down the distance you run and take it easy on yourself. If you find you need more energy for your run, Seltzer says that it can be helpful to restructure your meal timing so that you eat some carbs a couple of hours before you work out.

If you love indoor cycling:

An indoor cycling class is a good choice for people in the first couple of weeks of Whole30 because you’re in control of your pace and resistance. (Don’t worry, everyone at SoulCycle is looking at themselves in the mirror, not checking to see if you turned your resistance up.) “Focus more on low intensity, as opposed to being the fastest in the front row,” Swan says. “Keeping your pace slower will help you get through the transition and keep your workouts on the books.”

If you’re just starting to work out…

So you’re doing it. Jumping straight in. An entire lifestyle overhaul. To be honest, Seltzer says you probably shouldn’t. Whole30 takes a lot of work and prep, and it’s unlikely you’ll have room to do both. If you’re dead-set on starting a new workout plan while on Whole30, here’s his advice: “First pick something that you want to do, that you can do—not something you think you should do. And start slowly.” If you hate your workout, it’ll make it harder for you to motivate yourself to go do it. “Make sure you eat something before you work out, like a small protein and healthy fat, like avocado,” Swan says.

Patience pays off.

If you’re feeling too tired to even make it to your regular HIIT or yoga, it ‘s OK to skip a class or two—your energy should return in a couple of weeks. Think of this time as an opportunity to really dial in your form and technique for the movements you’re doing. “Be patient and listen to your body,” Swan says. “Most people will start seeing major improvements in their workout after 14-21 days on Whole30.” If you can stick it out through the first few weeks, you’ll find yourself with more energy than when you started—and that’s something I’d go a month without bread for.

Most importantly, Swan suggests you make a commitment to yourself and don’t get discouraged if you have moments of struggle. “These are the moments that make us stronger.”

Allie Flinn is an LA-based beauty, fitness, and wellness writer. She’s passionate about working out, neutral colors, young adult novels, and her rescue dogs. Follow her fitness journey on Instagram @allieflinn.