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Basic Nutrition Guide for CrossFit or High Intensity Functional Fitness


When it comes to getting fit and getting healthy, the entry ramp is pretty low. You learn that you need to get out of breath, lift heavy stuff, and if you want to lose weight, take in less calories than you put out. That’s it right? Sure, for a large majority of people who come into the exercise scene, if it’s CrossFit, weightlifting, running, etc… that’s the basis of how you exist.

What if you need a little more though? What if you want to pack on some muscle mass or lean down a little bit more than you currently are? (aka: Bust through a weight loss plateau). The solution typically isn’t to workout MORE, it’s to eat SMARTER. There’s a science behind muscle gain and weight loss and the primary variable is FOOD. Not just how you eat, but what you eat. Some would even argue when you eat as well, but that’s going to be beyond the scope of this article. Let’s talk about the basics: Macronutrients, Calorie Expenditure, and Caloric Need. Don’t worry if you don’t know what all those words mean. I’ll explain them and then we’ll break them down with math to show you how to setup your diet for success. Let’s take a quick look in this nutrition guide for CrossFit or other High Intensity Functional Fitness programs.

Gotta Get My Macros Bro!

At the simplest level all the food you eat is composed of 3 macronutrients: protein, carbohydrates, and fats (for the sake of simplicity, we’re not going to dive into complex carbs, mono vs. trans fats vs saturated fats). For the purpose of math and calculating how we should eat, we need to assign each of the macronutrients a caloric value. The below numbers are an average, but tend to be pretty accurate:

1 gram of protein = 4 calories
1 gram of carbohydrates = 4 calories
1 gram of fats = 9 calories

By using these caloric values for each of our macronutrients we can move on to the next step, determining our “burn” or our Total Daily Energy Expenditure

Finding our Total Daily Energy Expenditure

It doesn’t matter if you’re eating to lose weight or if you’re eating to gain muscle mass, you still need to know what your baseline caloric burn is. Once you’ve established that you’ll be able to determine what your caloric goal is for gain or loss.

I will say that the best way to do this is to shop around your local area and look for doctor’s offices that offer: Basal Metabolic Rate Testing, you’ve seen this referred to before as BMR. This is the amount of calories that your body burns just by being alive, no exercise or extra work factored in at this point. Think of it like the amount of calories you would burn during a rest day. Typically you can get these tests done pretty cheap, but shop around for the best value.

If you want to know an answer right now OR you’re like me and you hate doctor’s offices there are several online calculators that you could use. My suggestion here would be use all of them and do an average of the results that you get. That would be a little more realistic as some of these calculators give a good swing in the numbers. All of these numbers will be different per person depending on age, gender, lifestyle, etc…

  1. http://www.fitnessfrog.com/calculators/tdee-calculator.html
  2. http://iifym.com/tdee-calculator/ (there are 3 different formulas available here. I would do all 3 and average the result)

Once you have your TDEE (Total Daily Energy Expenditure / how many calories you burn a day at rest) we now need to adjust your intake based upon that number and your goals.

Determining your Caloric Goal

Ask alot of people in the fitness industry and they’ll tell you “Oh just add 500 calories to gain weight or subtract 500 calories for weight loss”. Here’s why I don’t like that.

Let’s pretend your TDEE is 3000 calories (typical with most males), 500 calories is about 17%…not too bad
But if your TDEE is around 1400 (typical with some women), 500 calories is about 36%

See the disparity there? If a woman would cut 36% of her calories to lose weight, she’s actually going to end up doing more harm to her body than good.

A better method that I tend to use is to say +/- 20% of your TDEE. So if you’re TDEE is 1400 calories you’re adjusting by about 280 calories each way. If your TDEE is 3000 calories then we’re talking 600 calories each way. This to me is a more realistic and safer way to approach it than a flat 500 calorie figure.

Breaking Bad on our Calorie Distribution

So know we know how many calories we need to eat in a total day. But how do we break those up over the course of the day? I’m not going to get into the 3 meals total vs. 3 meals and 2 snacks debate. I’ll let you decide based on what works with your schedule and lifestyle. But regardless of how you do it, we need to break it down something like the following:

Protein, this is your money macro right here. It’s essentially for muscle growth and retaining the muscle that you currently have:
1 gram per 1 lb of Bodyweight

Fats, your body needs these just to help run itself on a day to day basis. We want these to take up 30-40% of your diet.

Carbs, we’ll fill up the rest of the calories in our day with carbs. Most people give carbs a bad rap as well, but remember carbs directly translate to the building blocks are body needs to create energy. We can’t go lift heavy things if we don’t have a store of energy to use!

Example of a 180 lb. man with a TDEE of 2000 calories.
Fat – 35% of 2000 cal is 700 cal, 700/9 (number of calories per gram of fat) = 77-78 grams.
Protein – 180 lbs. = 180 grams. (multiple by 4 to get calories = 720)
Carbs – 2000 cal – (700 cal (fat) + 720 cal (protein) = 580 cal. 580/4 (number of calories per gram of carbs) = 145 grams.

Again, this is a basic breakdown, if you’re really trying to lean out or “cut” like body builders do, you’ll probably want a phase with a lot lower carb count. 10-15% and a higher protein count. This breakdown however should be good for most CrossFit and functional fitness enthusiasts.

So how do you do it on a day to day basis? If you want to get really serious about it (and trust me you need to if you want visible abs or +20lbs of muscle in a year) then you need to invest in a small kitchen scale, usually around $20 or less on Amazon.

Then let’s take breakfast, let’s say I scramble 3 eggs, have a slice of avocado, and some sweet potato hashbrowns. I would weigh the eggs, and subtract that from my protein grams, the avocado from the fat, and the sweet potato from the carbs. I’d do that with every meal.
I have found that it does tend to work better if you PRE plan your meals so you know you’re hitting all your numbers throughout the day.

Is this going to be extra work for you? Yes it will. But you can’t really get the benefit if you aren’t willing to put in the work!

How do you eat during the day? What else would you add to this guide? Let me know in the comments below!