Working Out? Pay Attention to These 3 Numbers

When I first started getting in shape, about two years ago, I really didn't know what I was doing. I mean, I kept track of my weight, of course, but I didn't know what else I needed to be keeping track of. BMI, protein intake, body fat percentage - the list seemed endless. Plus, I truly hate micromanaging, and keeping track of all that just seemed tedious.

However, as I've grown as a weightlifter and my conditioning has gotten better, I've learned that some of these numbers can tell you quite a bit about how in shape you really are. The key is to keep track of only that information that can help you along your fitness journey, while casting aside all the superfluous stuff.

So, here are some numbers you should really pay attention to:

Body fat percentage. I've always loved the phrase, "Abs are made in the kitchen, not the weight room." I think it's a great way to show how important it is to keep track of your body fat percentage. No number is more telling when it comes to fitness, and other useful information, like your lean muscle mass (body weight - body fat), can be gleaned from it. The best way to get this number down is through your diet.

[Read: 8 Essentials To Stuff In Your Gym Bag.]

Amount of weight and repetitions. Like I said, I loathe micromanaging. That's why I don't really count calories (although, that doesn't necessarily mean you shouldn't) and why, for a long time, I didn't keep track of how I was performing during my workouts. As I increased my number of workouts from three to four per week, however, I realized that I had no way to keep track of my progression. So, I started taking a notebook with me during my workouts, and it's helped me tremendously. In addition to being able to see exactly what I did in my previous workout, it motivates me to outperform myself on every exercise - and lets me know what I need work on and where I need to increase weight or reps.

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Protein intake. This one is specifically for those who are trying to gain lean muscle mass. Now, the Centers for Disease Control and Prevention recommends you get about 56 grams of protein per day. But, that's really just for weight maintenance. The general rule of thumb for muscle gain is 0.8 grams per pound of desired lean muscle. For example, I am looking for about 185 pounds of lean muscle (eventually), so I take in about 148 grams of protein per day. Definitely keep track of this one.

As far as what you don't really need to worry about, there's only one thing I'd discourage you from paying attention to, and that's your BMI.

Here's my issue with BMI: It doesn't take body composition into account. For example, let's take two men (call them Allen and Bob) who are 5 feet 9 inches tall, which is an average male height. Both weigh 185 pounds, which gives them a BMI of 27.3 - well into the "overweight" category.

[Read: 7 Mind-Blowing Benefits of Exercise.]

Now, here's where body composition comes into effect. Let's say Allen is a generally lazy person with a relatively static job, while Bob is an active person who exercises regularly and works a job that requires a lot of movement or heavy lifting. Clearly, the body compositions of the two men are totally different. However, their BMI remains the same.

Obviously, BMI leaves something to be desired when it comes to assessing an individual's fitness level. It's great for letting someone know how they are "medically" perceived, but I'd stick to body fat percentage if you want to know how fit you really are.

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Hungry for more? Write to eatandrun@usnews.com with your questions, concerns and feedback.

Steven Holbrook is a senior majoring in journalism at The University of Alabama in Tuscaloosa, Ala. In addition to finishing up his degree, he is currently working on attaining his personal trainer certification. He wants to use his fitness journey to help others attain their own fitness and nutrition goals. He loves a good omelet, aggravating his dog allergies and superhero t-shirts. Follow him on Twitter at @iHolbrook.