That's just the thing, there's so much of this stuff looking at specific breeds of mice, particular diets. Even just the fact that various fiber supplements will be pelleted along with other ingredients into chow, the mono-chow, all hard little pellet diet is a little weird.

I've seen two studies where cellulose has been deadly to mice. One study used cellulose as the fiber for ketogenic mice, they had to replace the cellulose with another fiber source six months in because the mice were dying prematurely. Another looked at 25 different macro-ratios and also nutrient density for longevity, they manipulated nutrient density by adding various levels of cellulose, seven out of eight of the shortest-lived groups were on the lowest density, highest cellulose diets. Do I think celery is deadly? Saying that based on this data would be silly, it's an artifact of having a diet of hard little pellets. They sort of ignored the deadly effect of cellulose in the conclusions and concentrated on the idea that having a higher carbohydrate to protein ratio somehow prolonged life, although that was a much weaker effect than the apparent deadliness of cellulose.