My bad, i saw FDA and that's the links i meant to attach! Hopefully one or more will help
Serving Size [21 CFR 101.9(b)(1)]
Serving size must be based on the established reference amount referenced in 21 CFR Section [section] 101.12(b)(See Attachment # 5) except:
- Food available only through a weight control or weight maintenance program, may determine a serving size that is consistent with the meal plan for their program. The principal display panel for such products must bear the statement "for sale only through the _____ program" with the blank filled in with the name of the program. However, they must use the established reference amounts to determine if the product qualifies to make a claim.
- Serving size is expressed in common household measure (i.e., cup; tablespoon, teaspoon; piece, slice, fraction (e.g., 1/4 pizza); ounce, fluid ounce) and followed by the equivalent metric quantity in parenthesis. When ounces are used a visual unit must be provided after the metric equivalent (e.g. 1 oz (28g/1" X 1" CUBE) The metric quantity is not required for single serving containers unless nutrition information is required on a drained weight basis [101.9(b)(5)].
- A package that is sold individually and contains less that 200% of the applicable reference amount is considered to be one serving. However, for products that have reference amounts of 100 g (or ml) of larger, manufacturers may decide whether a package that contains more than 150% but less than 200% of the reference amount is 1 or 2 servings. When a product contains 200% or more of the reference amount, the manufacturer may label the product as a single serving if the entire package can reasonably be consumed at one sitting [101.9(b)(6)].