[Grammar] A lot of x, y, and z is/are ...? Subject Verb agreement

[cubezero2]

Hi, everyone.

One of my friends encountered the following sentence.

A lot of ice-cream, hamburgers and cola is not healthy.

My friends' opinions are divided as to whether are, instead of is, should be used here.

In Practical English Usage, Michael Swan claims:

Many singular quantifying expressions can be used with plural nouns and pronouns; plural verbs are normally used in this case. (503.2 quantifying expressions)
A lot of social problems are caused by unemployment.


When two singular subjects are joined by and, the verb is normally plural.
Alice and Bob are going to be late. (509.2 coordinated subjects)

Personally, I think there is a mismatch between the two rules. Plural nouns, in his words, may refer to a noun in its singular form and it's quite clear coordinated subjects, as Michael Swan calls it, consist of at least two nouns. Yet, in the sentence in question, there are three nouns.

On a side note, I've done my homework with the help of Bing.com and strangely it seems in all the sentences and examples I've found there is only one noun used after a lot of.

I've only found one source that may shed light on the issue.

Quantifiers function as adjectives in English, no matter what their inner structure is, and they are never considered the subject of the sentence. The correct verb form is determined by the real subject of the sentence, i.e. by the noun or pronoun modified by the quantifier.
https://jakubmarian.com/a-lot-of-a-number-of-a-couple-of-singular-or-plural-verb/

According to it, I would have to rely on 'the x, y, and z' part to find out the answer. Since ice-cream, hamburgers and cola are not normally considered as a single idea. Are, instead of is, should be used here.

I'd like to hear your opinions.

Many thanks

Richard

 

[Roman55]

A lot of anything is usually not healthy. The subject of the verb is a lot, not the nouns that follow it. It has the meaning of a large amount.

 

[jutfrank]

I see are as incorrect.

Similar to Piscean in post #2, I interpret the thought to mean [Eating] a lot of ice cream, hamburgers and cola is not healthy. I think it's hard to interpret this in any other way. It is the diet that is unhealthy.

However, without a lot of, we interpret a different thought:

Ice cream, hamburgers and cola are not healthy.

Here, there is a clearly composite subject, so are is appropriate. It is the food items that are unhealthy.