A varied diet is a diet that includes a wide range of different foods — across and within the food groups — rather than relying on a narrow set of staples. Variety is the simplest insurance policy in nutrition: no single food supplies every nutrient, but a rotating cast of vegetables, fruits, grains, legumes, nuts, dairy or alternatives, and protein sources covers the gaps each leaves. It also spreads risk — of contaminants, of boredom, of overexposure to any one compound — and supports a diverse gut microbiome, which thrives on diverse fibres. Dietary guidelines worldwide phrase it similarly: eat a variety of foods. It is the least technical and most robust nutrition advice there is.