Why did Pliny the Elder criticize luxury in his discussions of medicine and diet?

In his encyclopaedic work, the Natural History, Pliny the Elder criticized luxury within his discussions of medicine and diet based on both moral and medical grounds.1

Pliny viewed the pursuit of luxury as having deleterious effects on health and society. His critiques were often woven into his observations regarding the commercial sources and high prices of ingredients used in costly drugs. By highlighting these excesses, Pliny provided significant insight into the lifestyle and values of contemporary Roman society, suggesting that such indulgence was detrimental to the well-being of the individual and the broader public.21