I exercise regularly and eat “healthy”, does caloric intake actually matter?
By Nicki Hubers-Hall, MS, CNS, LDN
If your goal is weight loss or maintenance the answer is a resounding YES!!
In order to lose weight we have to eat in a deficit of 3,500 calories, and in order for you to know how to eat in a deficit you need to understand how much you should be eating. To do this we need to calculate your BMR or basal metabolic rate which is the amount of calories your body needs to basically function without out any activity. Here is a BMR calculator http://www.bmi-calculator.net/bmr-calculator/, after you calculate that you than account for activity by multiplying specific numbers that relate to the number of days you are active…
If you are sedentary (little or no exercise) = BMR x 1.2
If you are lightly active (light exercise/sports 1-3 days/week) = BMR x 1.375
If you are moderately active (moderate exercise/sports 3-5 days/week) = BMR x 1.55
If you are very active (hard exercise/sports 6-7 days a week) = BMR x 1.725
If you are extra active (very hard exercise/sports or 2x training) = BMR x 1.9
For weight loss you do not want to subtract more than 700 calories from this number or you will risk slowing the body’s metabolic functions. This will yield you an average weight loss of 1.4 lbs per week, based on a 4,900 weekly caloric deficit.
Example 1: 165 LB Female that does cross fit 3 times per week
BMR = 1532 x 1.55 = 2,374 calories daily for weight maintenance
2,374 – 500 for weight loss = 1,874 daily calories for a 1.4 lb weekly weight loss
Example 2: 165 LB Sedentary female
BMR = 1532 x 1.2 = 1,838 calories per day for weight maintenance
1839 – 500 for weight loss = 1338 calories
So just by working out moderately 3-5 days per week your body needs 536 more calories per day. These additional calories are an important part of the process.
Now let’s try to lose this same amount of weight by just working out a couple times a week and not changing a single thing about your current diet…..
You would have to run 49 miles a week to have the same 4,900 calories deficit. Now we all know this is not an exact science as exercise does increase your metabolism so you will burn calories more efficiently throughout the day not just while you are working out, but it’s a jumping off point. A typical Cross fit workout is going to burn about 12 calories for every minute that you are active. A 20 minute WOD will burn 240 calories, plus about 100 more calories for 20 minutes of strength training. How many 20 minute WODS/20 minute strength training sessions would you have to do to burn off one pound….about 10, and this is pending you are eating only your maintenance calories and no more. If you are working out 3 days per week and burning 340 calories each time or 1,020 calories weekly, and you overeat by 145 calories per day you will lose ZERO weight, and we all know how easy this is to do.
This is why caloric intake is important!! You absolutely CANNOT out exercise a poor diet. And by poor diet I do not mean you are eating unhealthy foods all the time. It could simply mean tweaking the already healthy foods you are eating by a mere few hundred calories per day. However, you cannot do this unless you track your food.
Ask yourself this question….would you drive a car around without a gas gauge, how would you know when the tank is empty, how would you know when it’s full. Think of your caloric intake as your fuel. Invest the 5-10 minutes per day that it will take you to track your food in an app, it could be what separate’s you from success or failure.