Still, if it's a process as poorly understood as dying of old age, saying "made me wonder if any of her longevity can be credited to having a severely calorie restricted diet" seems like a reasonable response.
Some research on worms, mice, and monkeys has pointed at caloric restriction and/or a carb-free diets helping with longevity. If I recall correctly, these two strategies help with insulin sensitivity and other hormones that are known to serve as regulators in certain DNA repair pathways.
I think posters above are not supposing that caloric restriction could have helped at random. Rather, they have read about it helping with longevity -- unlike odd numbers of food.