Don't forget that enjoying meals with other people and having direct connections to the earth and the people who produce your food is socially and emotionally healthy. The psychological damage to most people due to a strict Soylent diet would be significant, and psychological stress causes physical health problems.
So if someone is looking for optimal food inputs with respect to longevity, I think it's relevant to point out that how you eat may be almost as important as what you eat. That's all, really.
