Nutrition¶
Each food may have its nutritional value specified in multiple ways; for example, you may want to list the nutritional information for a single large potato, or for a specific weight or volume of potatoes. This nutritional information is managed by the Nutrition app.
You can click the Add link to add nutritional information for any food, or Change to view the list of existing nutritional information. There are two ways to add new nutritional information; you can do it through via the Nutrition app, where you’ll get a form like this:
An easier way is to add nutritional information directly to the Food form:
Using a standard nutrition label from the food you’re entering, simply enter the numeric values for each nutrient. It’s best to use a quantity with a Unit of gram whenever possible, though you may want to omit the unit for certain foods if they are not normally measured by weight or volume. For example, the nutritional info for one egg could have a Quantity of 1, with the Unit omitted.
Density¶
The most accurate way to measure nutritional information is by weight, and Vittles uses grams as a basline for all calculations related to nutritional information. But it’s quite common for recipes to specify volumetric measurements–1 cup of flour, 2 tablespoons of honey, etc.–and you can’t convert volume to weight unless you know the density of whatever you’re measuring.
Water has a density of 1.0 grams per milliliter, but most foods have a higher or lower density. For example, all-purpose flour weighs about 0.42 g/ml, while honey weighs about 1.44 g/ml. If you have 1 cup of something, Vittles doesn’t know what it weighs unless it knows what’s in the cup. If it’s flour, it weighs 100 grams, but if it’s honey, it weighs 340 grams. If it’s material from the core of a white dwarf star, it weighs 230 metric tons.
For this reason, correct calculation of nutritional value is very dependent on having correct densities for your foods. The default value of 1.0 g/ml may be a reasonable approximation in most cases, but if you notice that your recipes containing “1 cup chopped nuts” have thousands of extra calories, better check the density of your nuts.