The FastDay Forum

I just had my TDEE calculated on two different sites: Caloriecount.com, and thefitgirls.com, and they are vastly different. Thefitgirls.com caculated my TDEE at 1808, and caloriecount.com at 1690. Obviously, that's a huge difference, and it would affect how much I lose or gain, or what really is my 25% for my fast days. Both sites asked the same questions- my age, height, weight, and daily exercise level. How can they come up with such a big difference? Can anyone recommend to me a good, reliable website where I can get my TDEE calculated? Thanks!

[carorees]

There are several different mathematical formulas that are used. It's hard to say which is the most accurate. It's best to check on several and start with the middle one!

There isn't "one true number". It's an estimate. The amount of energy you use each day (which is what TDEE is), will not be the same every single day:
it'll depend on whether you ran for the bus or just walked, whether you went to the gym that day and gave it your all, or just phoned it in. I try to apply a tolerance level of +/- 10% on ANY figures, including the calories I'm eating. 1808 using that 10% either way gives a range of 1628 - 1988, and 1690 could be between 1521-1859. So they're not THAT different.

I'd go with aiming for around 1700.

Thefitgirls.com caculated my TDEE at 1808, and caloriecount.com at 1690. Obviously, that's a huge difference, and it would affect how much I lose or gain, or what really is my 25% for my fast days.

The original advice was to eat 500 calories or "about a quarter of your recommended calorie intake" so you could start there and adjust based on results.

1690 and 1808 could be stated as 1749 +/- 59 ie +/- 3.4% so they're the same number within the accuracy of the estimates.