Which? has done a survey on how serving sizes are misleading and inconsistent based on UK consumers expectations and appetites.
I have noticed odd serving sizes on the nutrition labels, especially where a pack does not have a multiple of the stated serving size, or the serving size is an odd measure to a fractional gram.
My conclusion is producers are gaming the system to claim peak nutritional benefits and minimal negatives when neither may reflect practical reality.
It is time for reasonable, consistent serving sizes. I would add as well as sizes that are even multiples in the packages. Buying a package having an odd number of serves such as 2.3 serves in it would not be most consumers expectation. Anything less is implied as gaming, especially when the confusion is compounded by multiple package sizes of the same product from the same manufacturer claiming differing sizes, as referenced in the article.
It is easy to put what seem exceptions or problems but there is no intention that a serving size is universal.
Common sense applied to the issue would suggest if say a cereal had a serving size of 100g, that would be the same on the 500g, 1kg, or 5 kg box of the same cereal. If a package had 400g of food, a serving could be a reasonable divisor such as 100g or 200g not 148.3g or 94g.
Getting the same serve on each package size could be more challenging but one thing at a time.
The article addresses a perceived problem I agree with, if one reads it. One does not have to agree it is a problem.
Considering just one food the serving size for a meal for a beefy young man who does hard physical work is nothing like a snack for a small elderly person who does very little. I donāt know how you would usefully produce a figure that covers both.
To me the concept of serving size is not very useful. By all means insist that nutrients are given per pack or per 100g, or both.
I get annoyed with serving sizes that use a fraction of an item eg biscuits where the serving size is 1.3 biscuits.
My other beef is where they stipulate the weight of serve, but not how many items eg Box 375g 15 biscuits, Serving = 25g. It takes some calculation to work out that it is one biscuit. Worse if they are dealing with fractions.
I take more notice of the 100g panel as that gives me the % and the overall health of the product.
From most serving sizes I read (read the link for background) the specified serving sizes seem much less than anyone larger than a pre-teen might eat in a go.
From the evidence I can find, you are using a portion as a synonym for a serving, and they are different. A portion is what one eats that can be any multiple of servings.
From the different serving sizes used on differed sized packages it suggests people will eat more from a larger package and less from a smaller one. How valuable is that information? The portion one eats will be what it is.
As for the claimed serving sizes on labels I find most are almost insultingly irrelevant. 1 slice of sliced bread or a single cookie makes sense although many of us eat 2 slices of bread and multiple cookies as our portion. Crisps (aka chips)? Serving sizes seem to range from 25 to 45g even though the average weight of a single crisp seems to be taken as 1.2g.
If a serving is how much a person typically eats this only confirms my feeling that it is irrelevant. If we all ate between 50 and 100 g of a food then saying 75g is typical may not be completely accurate but has some meaning.
If we might eat between 20 and 250 g then 75g is not typical of anything. The higher the variance the less useful any measure of central tendency is going to be.
It seems to me serving size is pretty arbitrary and using it to assess the content of some component of food (like sugar or salt or calories) that you may want to keep under control is useless as the chances are you as an individual donāt eat that amount or anything like it.
Of course if the serving size is deliberately set very low and most would eat much more of that food it is just abetting self-deception.
