Dietary guidelines are the public advice on healthy eating issued by governments and health authorities — the official answer to “what should we eat?” They translate nutrition science into practical patterns: plenty of vegetables and fruit, whole grains, lean proteins, limited saturated fat, salt, and added sugars, water as the main drink. Most countries publish their own, often visualised as a plate, pyramid, or pagoda, and they shape everything downstream — school meal standards, hospital catering, food labelling, and industry reformulation targets. The guidelines are reviewed periodically as evidence evolves, and each revision is politically charged, since the advice moves markets worth billions. Critics argue they are too timid or too influenced by industry; defenders note they must be both evidence-based and achievable. Either way, they are the closest thing nutrition has to an official consensus.