In this activity, you will learn how to calculate the values necessary for understanding your diet and identifying your dietary needs.

The activity will walk you through four strategies for mastering different kinds of calculations, while also introducing you to a selection of the dietary recommendations.

Strategy 1: Think division when calculating percentages.

Percentages are useful as tool for determining how well your diet meets recommendations. The closer you are to consuming 100% of the Recommended Daily Allowance (RDA) for a nutrient, the better.

To find the percentage that you consumed of a nutrient's RDA, follow these steps.

1. Divide the amount that you consumed by the RDA for the nutrient. For example, if you were a man who consumed 45 mg of vitamin C, you would perform this calculation.

45 / 90 = 0.5

2. Multiply the decimal number by 100 to find the percentage.

0.5 × 100 = 50

Starting with the RDA for vitamin C for men and assuming you consumed 45 mg of vitamin C, we calculated that you consumed 50% of your recommended vitamin C.

These same steps can be used to calculate any percentage: divide and then multiply by 100.

Strategy 2: Think multiplication when calculating kilocalories.

The Acceptable Macronutrient Distribution Ranges (AMDRs) are given above as percentages. How can you know that your diet is within the acceptable range? It is helpful to calculate the AMDRs in kilocalories for your particular diet.

To find the AMDR for a macronutrient in kilocalories instead of percentages, follow these steps.

1. Divide by 100 to change a percentage to a decimal number.

45 / 100 = 0.45

2. Multiply the decimal number by your total daily calorie intake.

0.45 × 2000 = 900

Starting with the minimum acceptable percentage for carbohydrates (45%), we found that the minimum acceptable carbohydrate intake for a 2,000 kcal diet is 900 kcal.

Strategy 3: Think division when calculating AMDRs in grams.

Now we know how many kilocalories to eat, but Nutrition Facts Panels provide carbohydrates in grams, not kilocalories. How do we calculate the grams we need to eat?

To find the AMDR for a macronutrient in grams instead of kilocalories or percentages, follow these steps.

1. Recall your previous calculation of the Carbohydrates AMDR in kilocalories.
   Minimum acceptable carbohydrate intake for 2,000 kcal Diet: 900 kcal

2. Divide by the number of kilocalories per gram for the relevant macronutrient. There are 4 kcal per gram of carbohydrates.

900 / 4 = 225

Starting with the minimum acceptable kilocalories of carbohydrates in a 2,000 kcal diet, we found that the minimum acceptable grams of carbohydrates for that diet is 225 grams.

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Strategy 2 (Revisited): Think multiplication when calculating kilocalories.

Nutrient Facts Panels provide the macronutrient content of foods in grams but not in kilocalories. To find how many calories are consuming from a certain amount of grams of a macronutrient, simply multiply the amount in grams by the number of kilocalories per gram for that macronutrient.

20 (Grams of Carbohydrates) × 4 (kcal Per Gram) = 80 (Calories)

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Strategy 4: Think division, then multiplication, when calculating the RDA for protein.

The AMDR for protein doesn't tell the whole story; there is also a Recommended Daily Allowance (RDA) for protein. This recommendation is given in terms of the kilogram of body weight, so we'll need to calculate the RDA for our own body weight.

1. Convert your body weight in pounds to kilograms by dividing by 2.2, since 1 kilogram is equal to 2.2 pounds.

176 / 2.2 = 80

2. Multiply your weight in kilograms by the protein RDA.

80 × 0.8 = 64

Starting with the general RDA for protein, we calculated that the specific RDA for someone who weights 176 pounds is 64 grams.

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You have completed this activity!

Be sure to remember the RDAs, AMDRs, and other information you used. There are many more nutrient RDAs to learn!