Premise: In the consumer advocate's nation, food packages must list the number of calories per food serving. But most of the serving sizes used are misleadingly small and should be updated.

Conclusion: People eating typical portions today consume more calories than the package labeling appears to indicate that they will.

Option A - Incorrect
We only know about the serving sizes used which are misleadingly small and nit the number of calories per serving listed on food packages. This claim doesn't stand a chance to be the main point of the consumer advocate's argument.

Option B - Correct
This is the main point of the consumer advocate's argument. People today consume more calories by eating typical portions, therefore, most serving sizes used are misleadingly small and should be updated.

Option C - Incorrect
This option is not concrete enough as the main point of the consumer advocate's argument as this only conveys the information about "today" in the consumer advocate nation. Hence this claim is incorrect.

Option D - Incorrect
The serving sizes in the consumer advocate's nation were misleadingly small and they were set when people ate smaller portions than they do today. Note the word "average".

Option E - Incorrect
This option is incorrect because the misleadingly small serving sizes were set decades ago when people ate smaller portions which means they consume fewer calories as a result of the small portion. Hence, they didn't consume more calories, as this option portrays. So, this option is wrong.