sukanyar
sayantanc2k
The pronoun "that" would refer to "rate".
Although people in France consume fatty foods at a rate comparable to that (the rate) of the United States, their death rates from heart disease are far lower in France.
Thanks sayantanc2k for your reply. So, "the rate of the United States" seems unclear to me. I mean, is that valid? Do countries have a "rate"

?
Responding to a PM here.
"That" as a pronoun can serve as a "new copy" of a previously mentioned noun. In this case, we are trying to compare the separate rates - France's (death) rate and the United States' (death) rate. The rates are separate, but we don't want to repeat the use of rate so we use "that" to represent the US' rate.
Here is another example:
The money spent on food for three days at Disneyland is slightly less than THAT spent for an entire month at home (but only slightly).
Here "that" is referring to a different pile of money spent on food for a month, but it is still money so using "that" is appropriate.
KW
[Yes, I did just make a trip to Disneyland

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