Dietary means relating to diet or food. When doctors give dietary advice, they're recommending what foods to eat or avoid. A dietary restriction is a rule about what someone can or cannot eat, whether for health reasons, religious beliefs, or personal choice.

Someone with diabetes might need to follow specific dietary guidelines about sugar. A person who's lactose intolerant has a dietary restriction against milk products. Athletes often have special dietary plans designed to help them perform their best.

The word shows up frequently in phrases like dietary fiber (the part of food that helps digestion) or dietary supplement (vitamins or minerals added to your regular diet). School cafeterias sometimes label foods with their dietary information, showing calories, vitamins, and ingredients so families can make informed choices.

Notice that dietary describes things connected to diet, while diet itself refers to the actual food you eat. Your diet is what's on your plate; dietary describes decisions, rules, or information about that food.