

Why the most popular rule of weight loss is completely wrong - dlo
http://www.washingtonpost.com/news/wonkblog/wp/2015/07/28/why-the-most-popular-rule-of-weight-loss-is-completely-wrong/?tid=sm_fb

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sanjiwatsuki
The headline is misleading and clickbait-y.

The rule in question (3500 calories deficit results in one pound of weight
loss) is mostly true, even if oversimplified. The fact that your metabolism
drops as your weight drops just means that the calorie/day input needs to drop
correspondingly to maintain the same deficit.

As the article states, the fact that the weight loss isn't entirely fat is a
minor error. Thus, the 3500 calorie guideline is maintained, as long as you
remember that it is a deficit and not a static amount.

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PeterWhittaker
Not to mention that the article confounds calories, a physical unit of energy,
Calories, a unit of nutritional energy, and kilojoules, the preferred physical
unit of energy.

At one point, it indicates that 3,500 calories corresponds to a pound of body
weight, then later indicates this came from research suggesting that 3,500 kJ
corresponds to a pound of body weight and that this is where the 3,500
calories figure comes from.

Problem is, 3,500 kJ = 836 520.076 calories = 836.520076 Calories. So which is
it? 3,500 kJ per pound of body weight, 3,500 Calories, or 837 Calories, or
something else?

FYI: A nutritional Calorie is actually a kilocalorie (1,000 calories). One
Calorie = 4.184 kJ.

~~~
aylons
According to the Hacker's Diet [1], 3.500 Calories is equivalent to a pound.

[1] Admittedly poor reference, but in tone with the Hacker News. Also, the
author most probably sources from the same reference the article does for the
traditional conversion and I trust him to not mess up with units.

~~~
PeterWhittaker
Hmm, OK. Doesn't explain how the "3,500 kJ per pound" got in there - perhaps I
still have optimistically high expectations, but I would have hoped that
somewhere along the line the author or their editor would have noted that a
pound cannot be equivalent to both 3.5 Mcal and 3.5 MJ. But mayhaps I wax
pedantic.

~~~
aylons
You're right, I was also very surprised by this error and have commented on it
as soon as this was posted. I just wanted to elucidate the correct value.

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aylons
Wow, that is a blatant error in the very beginning of the article:

>> it was 3,500 kilojoules, otherwise known as calories

NO! Although calories and joules are indeed two measures of the same physical
quantity (energy), there is a conversion factor of 4 between them: 1 calorie =
4.18400 joules.

As a side note, the usual nutritional calorie (or "Calorie", with uppercase
'C'), is actually 1000 calories, or 4184 Joules.

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bruckie
This doesn't inspire confidence in the rest of the article: "...and found that
it was 3,500 kilojoules, otherwise known as calories."

[http://www.google.com/search?q=3500+kilocalories+in+kilojoul...](http://www.google.com/search?q=3500+kilocalories+in+kilojoules)

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gorena
Is this the most popular rule? I'd think that it's "eat below your TDEE".

