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First of all, the nutrition facts given by USDA doesn't make sense to me. I'll refer only to skinless facts. Chicken breasts have 120kcal and chicken legs have the same. I know chicken breast have more protein and less fat, however I think chicken legs are much fattier.

When the are roasted, chicken legs have a higher caloric value (174 kcal) than breasts (165 kcal). The same applies for chicken thighs, which have very similar values.

I tried to calculate the amount of nutrients/calories in a chicken leg, but I got incongruent results.

I weighted full chicken headquarters without skin and it was 266g. I bake it in the oven at 400F/200C for 40 minutes and it reached and internal temperature of 200F/93C.

Cooked weight was 225g. Bones was 64g. Therefore:

Raw meat: 266-64 = 202g ; 202g * 120kcal/100g = 242 kcal
Cooked meat: 225-64 = 161g ; 161g * 174kcal/100g = 280 kcal

So 280 kcal / 202g raw meat = 139 kcal / 100g raw meat

Why didn't they match? I think the are very well done, so they should have lost a lot of water. But they would have to lose more water so the calories match (In particular meat would have to weight 139g cooked).

  • Firstly, you can't just say "120 kcal"... it's has to be per something. What are you trying to do? Based on that first link, out of 100 g, 73.9 g is water... unless you burn your chicken to ash, you won't remove all of the water. – Catija Jun 19 '17 at 13:42
  • Firstly, yes, NeDark said "120 Kcal" instead of "120 Kcal/100g", but I think he was just trying to save space and complication. In his citation it is clearly called out as "value per 100g", and that is what he uses in his actual calculation. As far as "What are you trying to do?", I think he is trying to do a sanity check on the figures provided in different parts of the USDA website. If he takes a specific piece of chicken, and calculates the number of Kcal raw, and compares it to the number of Kcal cooked, he expects the numbers to be =. Removing all the water doesnt figur in this discusn. – Lorel C. Jun 19 '17 at 19:01
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The numbers in the USDA are empirically derived. They take several pieces of raw chicken (or rather, find others who have done that) and measure the calories. Then they publish the average number of calories between these pieces. Separately, they find measurements for cooked chicken, and publish that average.

Empirical measurements are never exact. The chicken pieces vary in calorie content, the measurement procedure varies, the calibration of the instrument varies, etc. So, you can expect quite a bit of spread. And it seems that this is what you are seeing here. The measurements of raw and of cooked chicken don't match up - this can happen. You usually cannot say which factor was responsible.

This also is a good reminder that it doesn't make sense to calculate calories to the gram, since the piece of chicken you hold rarely has as many calories as given on the label or in a database. The exceptions tend to be highly processed foods which have little variation.

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