How to calculate the calories in your food
Posted on | June 7, 2012 | No Comments
Calculating the calories in your own meals is quite easy. Divide your meal up into protein, carbs and fat and weigh the amount. Then calculate using the following equation for each component:
Protein: 4 calories per gram (16.7 Kj)
Carbs: 4 calories per gram (16.7 Kj)
Fat: 9 calories per gram (37.7 Kj)
Yes, each gram of fat you consume provides more than twice as many calories as a gram of protein or carbohydrate!
Here’s an example: You eat something that contains 10 grams of protein, 10 grams of fat, and 10 grams of carbohydrates
(10 g protein x 4) + (10 g fat x 9) + (10 g carbs x 4) = 170
That food would provide you with 170 calories. 40 calories come from protein, 90 calories come from fat, and 40 calories come from carbohydrates.
So…. for everyone out there doing theirs sum and examining food packets – you will find something that you shouldn’t immediately get concerned about:
The Numbers Don’t Always Add Up
If you check a food label you may find that the total number of calories listed doesn’t match the number you arrive at using the 4-9-4 method described above. The reason for the discrepancy may be that the figure for carbohydrates includes insoluble fiber, and the food manufacturer has accounted for this in their figure for calories.
Insoluble fiber passes through your body without being converted to a form that provides energy, or calories. Knowing this, the manufacturer may subtract the caloric value of the insoluble fiber (4 calories per gram) from the total calories figure. When they do this, the 4-9-4 method will give you a higher figure for total calories than the one you find on the food label.
You might think that you could subtract the figure for fiber from the figure for carbohydrates to correct the discrepancy. But the figure for fiber will likely include both soluble and insoluble fiber, and you’d only want to subtract the insoluble fiber. Unfortunately you have no way of knowing how much of the fiber is soluble, and how much is insoluble.
Calories in Alcohol: You will also find that the numbers do not add up when you are looking at the caloric value of liquor. This is because the total calories for liquor include the calories in the alcohol, and this is not addressed by the 4-9-4 equation. 1 gram of alcohol provides 7 calories.
Sometimes the numbers don’t exactly tally….. if you haven’t cooked it yourself, you should always ‘estimate’ and acknowledge that it’s going to be plus/minus your calculations. Also, if you are not a person who cooks regularly, you WILL NEVER KNOW what ingredients actually go into food in the first place to be able to calculate the calories.
There’s a debate going on about my posted Chicken Rice nutrition info. I have written 666 calories, but the 9-4-9 calculation says it should be 736 calories (70 calorie discrepancy)
Energy: 666 calories
Protein: 30 g * 4 = 120
Carbs: 55 g * 4 = 220
Fat: 44 g * 9 = 396
Should the total: 736 calories or is 666 calories factoring in the the fibre has been deducted?????? Who’s wrong – who’s right. Maybe everyone is…
I’m going to leave it as 666 calories – but do thank everyone for the feedback. If you want the numbers to tally, you can pretend that 1.5 teaspoons of fat have been removed which is about 70 calories or you imagine that soluble and insoluble fibre have been factored in. Plus / minus 70 calories.
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Tags: calorie calculator > calories in carbohydrates > calories in chicken rice > calories in chicken skin > calories in fat > calories in protein > how to calculate calories in food
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