Final answer:
To determine the percentage of calories from fat for a product, multiply the amount of fat in grams by the average number of calories per gram of fat and divide by the total calories per serving. The result can be multiplied by 100 to obtain the percentage. Serving size information is important for accuracy.
Step-by-step explanation:
To determine the percentage of calories from fat for a product, you can refer to the nutrition facts label on the product. Look for the 'Total Fat' value in grams and multiply it by the average number of calories per gram of fat, which is 9 Calories. Then, divide this result by the total calories per serving and multiply by 100 to get the percentage.
For example, let's say a product has 10 grams of fat per serving and 200 calories per serving. The calculation would be: (10 grams x 9 Calories/g) / 200 calories x 100 = 45% of calories from fat.
Keep in mind that this method assumes a serving size of a product. It's important to carefully read and follow the serving size information on the label to get an accurate percentage of calories from fat.