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

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

Next we'll look at carbohydrates.

Remember: 1g = 4cal

16 (g) x 4 (cal) = 64cal
from carbohydrates per serving

Protein has the same calories per gram as carbohydrates.

6 (g) x 4 (cal) = 24cal
from protein per serving
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.

that we know how grams are used on a nutrition label, what exactly is one gram?

Being able to visualize what one gram weights can be little difficult.
        So what are some common, everyday objects that weigh just one gram?

One dime weights about one gram

One paper clip weights about one gram


4g = 1 teaspoon


12g = 1 Tablespoon


3 teaspoons = 1 Tablespoon

10 teaspoons = 40g 1oz = 28g 1oz = 0.125cup
1oz = 29.57ml 1lb = 16oz 8oz = 236.6ml

1oz = 2 tablespoons


1oz = 6 teaspoons

1 tablespoon = 0.0625 cup 1 cup = 16 tablespoons
1 tablespoon = 0.5oz 1 cup = 48 teaspoons
1 tablespoon = 14.79ml 1cup = 8oz
  1 cup = 236.6ml