After switching up your diet and workout routine, you finally started to pack on some solid muscle—and people were noticing. Then the progress halted. Despite your continued efforts, your shoulders seemed to shrink, your biceps became less buldging, and your quads refused to grow any bigger. What gives?

A number of factors influence your body’s ability to pack on gains—your sleep schedule, your diet, your fitness program, even your state of mind. You could seriously go crazy trying to figure out what went wrong. To help you get to the bottom of things, we checked in with  Jim White, personal trainer and registered dietitian, and Jay Cardiello, celebrity personal trainer and star of ABC's My Diet is Better than Yours. Adjust your program witht their tips and you’ll be back to building that jacked physique you crave in no time.

1. You skimp on sleep

Plain and simple: If you’re not getting quality sleep each night, your muscles won't grow. “Lack of sleep increases your body's level of cortisol (a stress hormone), wreaks havoc on your body's human growth hormone, and inhibits your body from properly storing glycogen—all things that can have a negative impact on muscle growth,” Cardiello says. “Plus, if you're not sleeping, then you're not training at 100 percent and you’re not improving.”

The fix: Cardiello suggests aiming for seven and a half hours of shut-eye each evening. He also advises keeping stress levels low before hitting the sheets. That means shutting down all electronics at least 30 minutes before bed. If you typically have trouble dozing off, you might want to consider taking a hot bath or shower before bed.

2. You don’t eat enough protein

If you want to look more pumped, you need to pump up the protein. The reason: protein contains amino acids, the compounds that help build and repair muscle tissue. “If you don’t consume enough amino acids it can hinder your muscle growth,” warns White.

The fix: White suggests shooting for 1.2 to 1.7 grams of protein per kilogram of bodyweight each day. That means a 200-pound man should get between 109 and 154 grams daily. And remember, it doesn’t all have to come from things like chicken, fish, red meat, and eggs. Like their animal-based counterparts, quinoa and Ezekiel bread (to name just a few) are both sources of plant-based complete proteins, meaning they contain all eight amino acids your body needs to fuel muscles but can't produce on its own.

3. You’re a booze man

“It’s fine to enjoy a cold one every once in a while, but throwing back too many inhibits your body’s ability to help muscles recover,” says Cardiello. How? “When you drink alcohol, the body calls on antioxidants that are typically used for muscle growth to help metabolize the alcohol.”

The fix: If you want all your hard work to pay off, Cardiello suggests cutting out booze altogether. Not an option? Limit yourself to one evening of indulgence per week and follow each round with a glass of water to slow your pace and reduce the number of drinks you down throughout the evening. Better yet, cut yourself off after three drinks—beers, cocktails, or shots, it doesn't matter; three's the magic number. Simply knowing your drink limit ahead of time can help you stay on track with your goals.

4. You’re doing too much cardio

If you recently upped your weekly mileage or started taking a weekly spin class with your girlfriend (no judgment), that could be the reason you’re looking a little on the puny side. “While cardio is great for fat loss, if you do too much of it, it can put your body in a catabolic, or muscle-burning state,” warns White.

The fix: “If your goals are to increase size and strength, cardio workouts should not dominate your program,” says White. “HIIT workouts and easy cardio sessions can be slotted into your program, but your first priority should be fitting in three or four weight training days. If you don’t tend to get too sore between workouts, feel free to add in a cardio session here or there, but not at the expense of your recovery.”

5. You’re overtraining

Not only does overtraining up your risk of injury and workout boredom, it can hinder your progress, too. “Many guys think the harder they go, the bigger the gains, and that’s not true,” Cardiello tells us. “If you're not taking time away from the gym, your body doesn’t have time to rebuild itself stronger and bigger than it was before. When I worked as a strength coach for the Tampa Bay Buccaneers, we always worked in rest days throughout the players training cycle.”

The fix: Cardiello suggests taking one or two days off for every seven days of training.

6. You shun carbs

While nutrient-void sources of carbs (candy, pizza, white bread, etc.) shouldn’t regularly make an appearance in your diet, it’s important to remember that all carbs are not the enemy. In fact, cutting back on carbs too harshly may be the very reason you're starting to look a bit flabby. “When you're low on carbs, you’re not giving your muscles the glycogen they need to hit the weights hard. This can affect muscle growth and make you feel weak,” explains White.

The fix: Keep complex, slow-digesting carbs in your diet plan (oatmeal, Ezekiel bread, whole grains, quinoa, beans, and fruit) and limit the processed starchy junk, says White.

7. You’re dehydrated

“When gaining muscle mass is the goal, it’s common for people to focus on ingesting carbs and proteins. But when it comes to water and adequate hydration, many guys leave their muscles out to dry,” says Cardiello. “Water is crucial for digestion so when you don’t get enough of it, it can negatively impact this process.” The result: Your muscles won’t be fed the nutrients they need to grow. “Plus when you’re not adequately hydrated, it’s more difficult to go all out at the gym, which can further impact your results.”

The fix: “Make sure you’re throwing back half of your body weight in ounces of water per day,” advises Cardiello. (That means a 200 pound guy should sip 100 ounces, or 12.5 cups of H20 daily.) “And if you're thirsty, you're dehydrated. So even if you’ve already hit your water quota, drink up.”

8. You don’t mix things up

“Your muscles need to be worked at different angles, volumes, and intensities to remain challenged. Working the same muscles, in the same way, can limit your gains,” White says.

The fix: Weather you’re an intermediate lifter or more advanced, you’ll likely need to change up your program every six to eight weeks, says White. “If you notice that your strength or physical results are starting to plateau, it’s a good time to weave in some new exercises and mix up your rep and weight selections. To challenge yourself further, make sure to include exercises that focus on your areas of weakness, whether that be quad strength or flexibility.”

9. You’re stressed out 24/7

“Stress increases levels of cortisol, the stress hormone that increases appetite and fat storage. It also inhibits the use of glucose by the body’s cells,” explains Cardiello. This can cause muscle proteins to break down, inhibiting muscle growth, according to a study in Medicine and Science in Sports Exercise.

The fix: Pinpoint the stressor in your life and squish it like a bug. “That might mean ditching a high drama girlfriend, asking your boss to decrease your workload, or enrolling in a yoga class,” suggests Cardiello. “Sipping rooibos tea can also help. It contains a flavonoid called Aspalathin, which has been shown to reduce stress hormones.”

10. You only train trophy muscles

If you only train what you can flaunt at the beach (i.e. biceps and abs) it won’t help you increase overall mass, warns White. “The legs and back are two of your biggest muscles. If you don’t train them, you’re not tapping into your full muscle growth potential. Plus, only training your trophy muscles can create injury-causing imbalances that could keep you out of the gym long term.”

The fix: Work all areas of your physique in equal amounts—and don’t forget to incorporate forward, backward, and lateral movements, and things like mobility training, says White.