gistfile1.md

Given that

• Diet Mountain Dew has "0 calories", and the second ingredient is orange juice concentrate.

• The FDA allows manufacturers to claim "0 calories" if a food has less than 5 per serving.

• Orange juice concentrate has 394 calories per 5 tablespoons.

We can deduce that

5 tbsp / 394 cal = 0.012658 tbsp / cal = 0.18769 mL / cal

Orange juice concentrate takes up 0.18769 mL per calorie.

If we assume that (1) all calories in Diet Mountain Dew come from orange juice concentrate, and (2) Diet Mountain Dew contains the maximum allowed number of unreported calories,

5 cal * (0.18769 mL / cal) = 0.93845 mL

A serving of Diet Mountain Dew is 12 fluid ounces, or 354.9 mL.

0.93845 mL / 354.9 mL = 0.00264 = 0.264%

Diet Mountain Dew contains, at most, 0.264% orange juice concentrate.

Further

• Unconcentrated orange juice contains 115 calories per cup.

We can deduce that

551 cal / cup = 2.3288 cal / mL = 0.42940 mL / cal

5 cal * (0.42940 mL / cal) = 2.1470 mL

0.93845 mL / 354.9 mL = 0.00605 = 0.605%

Therefore Diet Mountain Dew contains, at most, 0.264% orange juice concentrate, or the equivalent of 0.605% orange juice.

Also given that:

• The FDA states that less than 2% RDI is "not a significant source" of a vitamin 1
• It seems there is between 0% and 1% RDI Vitamin C per 1mL of orange juice concentrate (rounding up from your 0.93845) 2

It then seems like you could be pretty close, and almost no calories come from the aspartame.