# i don't understand: mice ate 30% less calories but ate the equivalent amount of protein

#### gene

##### New Member
(definition of: statistic noun -a fact or piece of data obtained from a study of a large quantity of numerical data.)

In a scientific study they say that the low energy diet mice ate 30% less calories but ate the same amount of protein as the high energy diet mice, but the protein intake was in the same proportions in the low and high energy diets so I don't see how it's possible to eat 30% less calories and have the same amount of protein because you either eat 30% less calories and therefore have 30% less protein or you eat the same amount of protein and you end up with the same amount of calories?

I don't understand how it is possible for the following 3 statements to all be correct:

“The % of protein (P), carbohydrate (C) and fat (F) (as a % of total energy). Each diet was replicated at 8 kJ g-1 (low energy), 13 kJ g-1 (medium energy) and 17kJ g-1 (high energy).”

“ Mice fed experimental diets containing 50% nondigestible cellulose ate a greater bulk of food (3.6 ± 0.4 versus 2.5 ± 0.4 g/day) but ingested about 30% less total energy than mice provided with food containing higher energy content...”

“mice on the low-energy diets were able to achieve their protein target through increasing chronic food intake (protein intake: 9.6 ± 4.3 kJ/day with low-energy diets versus 9.6 ± 6.3 kJ/day with high-energy diets)”

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#### hlsmith

I have not thought about stuff like this for 20 years and I imagine if you are reading the article you know your stuff. But the number of Kcals per gram of P, C, and F differ. So it is likely like the ways you can come up with $1.50 using pennies, nickels, and dimes, right. But if you ran numbers and they don't sum, contact the author. Though, I will acknowledge that I can recall the definition and conversions for kJ g^-1. Of note, I can see, 10/7.5 = 1.33. #### gene ##### New Member I have not thought about stuff like this for 20 years and I imagine if you are reading the article you know your stuff. But the number of Kcals per gram of P, C, and F differ. So it is likely like the ways you can come up with$1.50 using pennies, nickels, and dimes, right. But if you ran numbers and they don't sum, contact the author. Though, I will acknowledge that I can recall the definition and conversions for kJ g^-1. Of note, I can see, 10/7.5 = 1.33.
yes i also thought through the issue in that context but still the issue remains

#### gene

##### New Member
I have not thought about stuff like this for 20 years and I imagine if you are reading the article you know your stuff. But the number of Kcals per gram of P, C, and F differ. So it is likely like the ways you can come up with \$1.50 using pennies, nickels, and dimes, right. But if you ran numbers and they don't sum, contact the author. Though, I will acknowledge that I can recall the definition and conversions for kJ g^-1. Of note, I can see, 10/7.5 = 1.33.
yes i also thought through the issue in that context but still the issue remains

#### gene

##### New Member
i am just wrecking my brain to understand this, but the issue is how is it possible to eat 30% less kJ (in the low energy group versus the high energy diet group) and yet eat the equivalent kJ in protein in a pellet diet (consisting of all the ingredients mixed together not separable)? for example as per the table below, if the mice in the low energy (8kJ/g) eat 30% less kJ then the 17kJ/g mice, then that would be ~13kj and 7.5g of protein versus the high energy diet group's 10g of protein.
that is ~30% less kJ = 30% less protein

and yet the paper says:

“mice on the low-energy diets were able to achieve their protein target through increasing chronic food intake (protein intake: 9.6 ± 4.3 kJ/day with low-energy diets versus 9.6 ± 6.3 kJ/day with high-energy diets)”

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