get fit

know your numbers: the math behind weight loss

I am definitely not a weight loss expert. But I do know my numbers. In addition to the numbers that are associated with progress (weight and percent body fat) I also pay attention to my caloric needs. There are two really important numbers here: BMR and TDEE

BMR: Basal Metabolic Rate

This is how many calories your body burns before you do anything. Literally anything. You can calculate your BMR here with this helpful calculator. As a general rule of thumb, it’s a bad idea to eat less than your BMR. If you do, your body will perceive famine and that will cause your metabolism to slow down (never a good thing when trying to lose weight).

You can impact your BMR by decreasing your body fat percentage and/or decreasing your weight. This is one of the main reasons people tout the benefits of weight training instead of/in addition to cardiovascular training.

TDEE: Total Daily Energy Expenditure

Your TDEE is your BMR + the calories you burn from activity (TEA) + the calories your burn from digestion (TEF). Your TDEE varies with your activity level (the more you move, the higher your TDEE). The easiest way to calculate your TDEE is to use an activity factor and multiply that factor times your BMR. There are a lot of different sets of multipliers out there but I would just use the one that works for you. You could also wear a fitness tracker (like the fitbit) for a while and see how much you’re actually moving each day to get a better sense of your TDEE.

A good place to start trying to lose weight is your TDEE – 20%. I know it seems like a lot of calories, but it’s important to fuel your body properly (especially when working out).

Alternatively, you could just multiply your body weight x 10 (Women) x 12 (Men) to get a calorie target for losing weight. For me, TDEE – 20% and BW x 10 work out to be about the same.

My Personal Experience

In the past, I have tried more extreme forms of calorie restriction and I think the only consequence of that has been extreme feeling of deprivation (and eventual binging on high-calorie, sugar-filled foods) and the eventual slowdown of my metabolism.

I am still a work in progress but I am focusing on fueling my body with the best quality food possible and trying to eat within my TDEE – 20%. Of course the biggest determination of whether I will gain/lose weight is the quality of my food.

To me, the best quality of food looks something like this:

better quality foodBut every person has their own interpretation of what better quality food means to them. Whatever that interpretation is, we all know that Twinkies don’t qualify 🙂



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