There are 4 calories per gram of protein and carbohydrates. (leanhybridmuscle.com)
So if you take the protein as 400 calories (4 calories per gram of protein) this is 20 % of daily intake. (wholelifewell.com)
You can calculate roughly how many calories are in a treat based on its weight in grams by assuming there are 3 to 4 calories per gram in a treat. (thecaninechefcookbook.com)