Even the best of us make mistakes. After all, we're human and can't be perfect 100 percent of the time. While you might be hard on yourself for slacking on your sprint, stopping short on reps, or missing that box jump (ouch), don't worry—even athletes have off days.

Here to shed light on some of their beginner mistakes are members of Team Bodybuilding.com. By learning from their mistakes, and realizing not every misstep is a roadblock (and that, in fact, some help you grow), you can ensure that you don't commit the same fitness sins.

Mistake 1: Only Doing Fasted Cardio

While some research shows that doing fasted cardio in the morning can help you burn up to 20 percent more fat, it's not unequivocally the best fat-torching option. Sticking to only fasted cardio could be a mistake, according to Performix athlete Alex Silver-Fagan.

"While fasted steady-state cardio certainly has its time and place, doing it every single day for an hour on end will not help you achieve your goals faster," she says, speaking from experience.

While there's a time and place for lower-intensity cardio—such as if you're dieting or doing multiple intense lifting sessions a week—try to occasionally bump up the intensity if getting maximum results is your goal. Mixing up your routine with high-intensity interval training (HIIT) will help you level up your fat-burning potential—even after the exercise is done.

Mistake 2: Trying to Stay Lean Year-Round

When it comes to mistakes, one lesson Dymatize athlete Brooke Erickson had to learn was that staying lean year-round should not be an end goal.

"I made a big mistake in trying to stay lean and not allowing my body to recover properly," she explains.

While single-digit body-fat goals might be OK for the stage, it's important to remember they're not suggested for daily life. When you're at very lean levels, your immune system suffers and your recovery rate slows. Constantly staying lean while finding the energy to keep up with training demands can be nearly impossible.

You shouldn't be competing year round, so during the off season don't be afraid to take your body fat up a bit higher. Chances are, you'll feel a lot better because of it. Remember that if you want to make progress, devoting some time to building muscle and gaining a few pounds of body fat can be one of the best things you can do for your physique.

Mistake 3: Relying Too Heavily on Supplements

When it comes to proper nutrition, whole foods should be prioritized. But, it's a common mistake to rely on supplements too heavily instead.

"Early on in my career, I focused on taking supplements as a 'fitness fix' instead of trying to master my diet," says fitness model and Cellucor athlete Craig Capurso. "Supplements are designed to add support when you're lagging, but if you're lacking a proper diet, nothing is going to help."

It's important to have a good diet plan in place before even considering supplementation. That way, add-ons like whey and BCAAs will complement—rather than steal—the show.

Mistake 4: Doing Too Much, Too Fast

As far as mistakes go, NutraBio athlete Zane Hadzick was guilty of trying to do too much, too fast.

"I believed extremism would yield quicker results, but the reality is that results take time, effort, and consistency," he says.

When it comes to lasting success, there are no short cuts. Too many people rush into programs that are too intense for their fitness level, or start on extreme diets that are nearly impossible to stick with. You need to remember that your body has its limits, and a good program is one that you'll be able to stick with for the long haul.

Becoming truly fit is a lesson in patience. Enjoy the journey, and you'll be at the finish line before you know it.

Mistake 5: Not Eating Enough

Women often equate eating less with weight loss, and while cutting back might spare you a few pounds on the scale, it won't help grow a well-rounded physique. Just ask NLA for Her athlete Jessie Hilgenberg.

"I thought that to get the best physique, I had to eat fewer calories," she says. "My muscles weren't full, and I wasn't happy."

Under-eating is one of the top ways to seriously sabotage an otherwise good training program. Make sure you're providing your body with enough calories to push through hard days and grueling workouts.

Mistake 6: Not Sticking to a Well-Rounded Diet

Just as you can under eat, you can also eat too clean.

"As a fitness model, my biggest mistake was restricting my foods to only super-lean chicken, tilapia, rice, and veggies," says Bodybuilding.com athlete Lawrence Ballenger.

Eating only a handful of healthy foods might sound like a surefire weight-loss plan, but it's bound to get boring quickly. When it does, you're liable to pig out on all the sweets and treats—letting your diet crumble way more than it would if you allowed yourself a weekly cheat meal. When it comes to nutrition, you don't have to go to extremes.

The key? Making the most of nutrient timing. If you plan on having a sweet treat, for example, plan to eat it before your workout for the sugar rush, or directly after to replace glycogen stores.

Mistake 7: Paying Too Much Attention to Other Peoples' Opinions

When it comes to fitness, it's important to focus on yourself first.

"The biggest mistake I made as a beginner fitness spokesmodel was caring too much about what other people thought of me," says NPC competitor Amanda Bucci. "Comparing myself to them put me in a negative headspace. It took me some time, but I slowly realized that my unique personality and individual happiness mattered most."

Never change who you are as a way to "succeed." Embrace your own personality and stop the comparisons. Be you and work hard. The rest will come.