In yesterday’s post, I explained a simple trick to estimate the Phe content of sweets using the rank of gelatin in the ingredient list. Today I am going to give you another trick that my PhD student Jieun Kim and I developed.

It is also very simple trick: all you need to know is the size of a serving and the protein content of one serving. However, it requires a division, and thus you might need a calculator. On the other hand, you can generally expect a more accurate result than when using yesterday’s rank-based trick.

So here is the trick:

• Find the serving size in grams on the Nutrition Fact Label.
• Find the protein content of one serving on the Nutrition Fact Label. (We are assuming that it is rounded up to the nearest gram.)
• Then divide the serving size in grams by the protein content in grams plus 0.5 : (serving size in grams)/(protein content+0.5). Let’s call the number you get after dividing “X”.
• Then X grams of sweet contains less than 20 mg Phe.

For example, let’s look at Altoids mints. One serving of Altoids is 2 grams, and the protein content of Altoids is 0 grams (rounded to the nearest gram).  So we divide 2 by 0.5, which gives us X=4. Therefore 4 grams of Altoid mints (about 6 mints) contains less than 20 mg Phe. This happens to be the same result as we we obtained using the previous trick. However, usually the result will be different (and more precise).

Let’s look at another example: Jell-O Gelatin Snack. In that case, one serving is 96 grams, and the protein content in one serving is 1 gram (rounded to the nearest gram). So we divide 96 by 1.5, which gives us X=64. Therefore, 64 grams of Jell-O (about 2/3 of a serving) contains less than 20 mg Phe.

Note that this trick applies if the only ingredient containing Phe is gelatin. In particular, it does not work if the sweet contains aspartame.

I hope my explanation was clear. Let me know if you have any questions.

DISCLAIMER: Neither the author nor Purdue University assumes responsibility for damages resulting from using this Phe estimation trick. Please talk to your doctor or dietician before making any change to your diet.