That article in its entirety is interesting, because there are not two but four monkeys from two different studies. Two on "restricted diets," and two on "unrestricted diets."
In one study they fed both monkeys a highly processed diet of 30% sucrose. In the other study they fed both monkeys a less processed diet of 4% sucrose.
The monkey with the poor health outcome was the one allowed to eat as much as it wanted of the highly processed 30% sucrose diet.
So the "calorie restriction" seems to more likely just mean "don't eat more than 4% sugar, unless you are on an extremely calorie restricted diet."
I'm no expert, and I might be wrong, but generally I would argue against extracting conclusions (even layman conclusions) from two studies of a different species (!) with a sample size of 2 (!!!)
In one study they fed both monkeys a highly processed diet of 30% sucrose. In the other study they fed both monkeys a less processed diet of 4% sucrose.
The monkey with the poor health outcome was the one allowed to eat as much as it wanted of the highly processed 30% sucrose diet.
So the "calorie restriction" seems to more likely just mean "don't eat more than 4% sugar, unless you are on an extremely calorie restricted diet."