Whether you are a bodybuilder, an athlete or a student looking to put on a few pounds of muscle, arguably the most important determinant of muscle gain is what you eat — and how much you eat of it.

If you aren’t seeing the results you would like from your exercise efforts, you might be making a vital mistake that hinders progress.

“No matter what [the student’s] goal is, [succeeding is] 80 percent how you eat, 20 percent how hard you work in the gym,” said Pat Caulfield, American College of Sports Medicine-certified personal trainer at the Recreation Center. “Someone can exercise as hard as they want; if they’re not eating right, they’re not gonna see the results.”

Tearing your muscles in the gym won’t be very beneficial if you don’t have enough nutrients to rebuild a bigger, stronger muscle.

Your body needs a certain amount of calories just to survive. This is called basal metabolic rate, commonly referred to as BMR. These are the calories you burn per day doing nothing but vegging out on a couch. For a 5-foot-9, 160-pound, 20-year-old man, the BMR would be about 1,800 calories. A 5-foot-5-inch, 130-pound, 20-year-old women’s would be about 1,430 calories.

BMR doesn’t include calories required for activities you do throughout the day — whether that’s picking up a fork to eat stir-fry or picking up a barbell for dead-lifts in the weight room. With activities included, you could burn more than 2,000 calories per day.

Here’s the kicker: If you only consume the bare minimum number of calories you need, your body will use the bare minimum number of calories to rebuild muscle. It’ll patch up the tears you created working out, but more energy is required to actually add to your muscle.

Put simply, if you want to gain muscle mass, you must eat more.

Don’t be afraid of food if you’re working out consistently. On lifting days, eat an extra meal or an additional 500 calories. On non-lifting days, eat at least enough that you won’t lose weight.

Of course, if eating large amounts of food was all there was to getting jacked, we’d have an Arnold Schwarzenegger epidemic on our hands rather than an obesity epidemic. You still have to lift heavy weights.

“It’s gonna be lots of weight, it’s gonna be low repetitions and high volume — so that means a lot of sets,” said Zack Ioannides, National Strength and Conditioning Association-certified personal trainer at the Rec. “In [the hypertrophy] stage, you will be doing sets of eight to 12 reps and you’re gonna be doing three to five sets, resting around a minute and a half to three minutes [between sets].”

Lift and eat like an elephant to get bigger; got it. Anything else?

Why, yes: Don’t forget to sleep. Most of muscle rebuilding occurs during sleep, so it becomes even more necessary to get adequate rest if you want to gain muscle size.

For more advice on how to bulk up, visit the Rec for a free consultation with a personal trainer or registered dietitian.