The gram
(g) is the standard unit of mass in the
metric or System Internationale (SI) system.
The gram,
along with millimeters (mL), are the metric units used to measure
the serving size of food and are listed on the Nutrition Facts label
found on food products.
Looking at the nutrition label you can see that many of the
nutrients (e.g., fats, carbohydrates, and protein) are expressed in grams.
It's from this measure we can calculate out how many calories
in each serving comes from fats, carbohydrates, and protein.
At the bottom of most nutrition labels you
will find the gram-calorie equivalents for fats,
carbohydrates, and protein.
1 Fat gram = 9 calories
1 Carbohydrate gram = 4 calories
1 Protein gram = 4 calories |
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| Knowing these equivalents,
we can begin to calculate how much of the total calories per
serving each individual nutrient provides.
Let's start with Fat.
The label shows 3.5g of fat in each serving.
We know that each gram of fat is equal
to 9 calories, so:
3.5 (g) x 9 (cal) = 31.5cal
from fat per serving
--which is close to 30 stated on the label |
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Next we'll look at
carbohydrates.
Remember: 1g = 4cal
16 (g) x 4 (cal) = 64cal
from carbohydrates per serving |
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Protein has the same
calories per gram as carbohydrates.
6 (g) x 4 (cal) = 24cal
from protein per serving |
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In order to get the total
amount of calories per serving, we need to sum the total from
fats, carbohydrates, and protein.
31.5 (fats) + 64 (carbs)
+ 24 (protein) =
119.5 calories per serving.
Since labels do not use decimal points we round 119.5 to 120. |
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