What contradiction?
Both of those statements are factually correct.
They contradict themselves.
How can you calculate Calorie In (going into someone's body) if not everyone's body digests the same?
Rephrase:
Of the calories you take in when you eat, there is now way to determine how many you actually expend as energy.
Of the calories you take in when you eat, there is now way to determine how many you actually expend as energy.
That's a complete different statement from what you said earlier, and yes there's a way to determine that by how much weight a body loses.
Because calories in is the amount of calories the food has. Which can be calculated.
It's the actual usage (burning) of calories that cannot be calculated.
You've just confirmed the contradiction.
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