If you've ever tried to manually calculate the calorie content of a food item, meal plan, or recipe in NutriAdmin using the 4-4-9 rule, you may have noticed that the numbers don't always add up. In this article, we'll explain why this happens and why it's not a problem.
Where does NutriAdmin get nutritional information for foods, recipes, and meal plans?
NutriAdmin uses nutritional information from reputable sources to ensure accuracy in the nutritional analysis of foods, recipes, and meal plans. We use the following food databases:
- USDA FoodData Central
- McCance and Widdowson's UK Food Composition database
- AUSNUT food database
For more information, you can check our references here.
4-4-9 rule vs Food Databases
When determining the energy content of food, it is a common practice to use the 4-4-9 rule or the Atwater general factor system, which suggests that there are:
- 4 calories per gram of carbohydrates
- 4 calories per gram of proteins
- 9 calories per gram of fat.
However, it is important to note that this rule is only an approximation and not an exact measure, although it is a very good one.
Food databases such as USDA FoodData Central utilize chemical analyses, computations, and other methods to extract nutrition information from foods. This information is often more comprehensive and accurate than the 4-4-9 rule. Because of its reliability, online food nutrition databases generally draw from these sources.
4-4-9 rule vs Atwater specific factor system
The Atwater specific factor system takes into account the different energy values of proteins, fats, and carbohydrates based on their heat of combustion and coefficients of digestibility.
This differs from the 4-4-9 rule, which uses average values for these nutrients. The 4-4-9 rule normally gives good approximations, but some other foods deviate from this number.
For example, in Atwater specific factor system, protein from eggs is 4.36 kcal/g while protein from potatoes is 2.78 kcal/g.
This article by the Food and Agriculture Organization explains their differences further, including a table of Altwater specific factors for selected foods.
Comparison
4-4-9 rule and Atwater specific factor system comparison on a piece of boiled potato with skin on (136 g):
- 27.3 g of carbohydrates
- 2.54 g protein
- 0.136 g fat
4-4-9 rule:
- 27.3 g x 4 = 109 kcal from carbohydrates
- 2.54 g x 4 = 10 kcal from protein
- 0.136 g x 9 = 1 kcal from fat
Total: 120 kcal
Atwater specific factor system:
- 27.3 g x 4.03 = 110 kcal from carbohydrates
- 2.54 x 2.76 = 7 kcal from protein
- 0.136 x 8.37 = 1 kcal from fat
Total = 118 kcal
If you compare the USDA Food Database to the Atwater specific factor system, you'll see that they show the same result of 118 kcal.
Other factors
Other possibilities for issues could be if you have imported a recipe from the internet or added a recipe or custom food, and perhaps there is an error in the data entered.
It is possible to create a custom food and specify 100g of protein, but forget to input calories which can result in inaccurate data. Additionally, there may be issues when copying recipes from URLs, as shown here, which can also lead to incorrect data.
Make sure to double-check the nutritional information for any custom foods, recipe URLs, or your own recipes in NutriAdmin to avoid errors.
If you notice a significant discrepancy, please let us know at team@nutriadmin.com. We can investigate any potential issues and make the necessary corrections.