- Use that average total calories.
- Subtract your daily caloric expenditure from exercise.
- Divide that number by your fat free mass in kilograms. (remember kilograms is weight in pounds divided by 2.2)
Calculate fat free mass. Take Body fat % x body weight. If your body fat percent is 25%, then .25 times your body weight.
So 130 lbs with 22% body fat. Fat mass is 28.6 lbs. 130-28.6 = 101.4 lbs ffm
101.4 divided by 2.2 = 46.2 kg ffm
If average daily calories consumed 2100 kcals.
Energy expended with a 45 minute walk + weight training + 10 minutes intervals = 108+ 159 + 120 = 387 kcals expended (rounding up to 400kcals)
2100- 400= 1700 kcals divided by 46.2= 36.7
So based on this, I’m not in an alarmingly low state but low enough to be aware I should consciously start adding quality calories especially around workouts. When you do the calculation, about 45 is a good number to aim for or 50 if you’re training hard regularly. I’m not and some days much less than I’d like to but we all have to remember we may be slowing our metabolism by eating too little and compromising our body’s ability to regulate thyroid, proper immune function, metabolic function, mood or more.
Your exercise may or may not be affected. At first. If you’re an athlete, performance most likely will be negatively impacted. The rest of your life and physical function will suffer first. It might be happening at such a low level you don’t notice it, until cumulative effects set in.
Helpful? Share this with a friend. Low energy availability isn’t something talked about openly often enough. Instead we’re bragging about how long we’re fasting or doing HIIT. Potentially, we’re contributing to the problem: keeping score in the wrong game.