National Grain-Free Day 2021: Why We Go Gluten-Free For The Occasion KEY POINTS People can try out new grain-free diets on the day Grains are important for a healthy diet, but some people can't eat them Sunday marks the National Grain-Free Day. As part of it, friends and families can come together for a whole day dedicated to eating only grain-free meals, from appetizers to snacks and dessert. This was started by Siete Family Foods in 2019. But what's the purpose of this simple event? According to National Day Calendar, it is an occasion for people to be with their loved ones who cannot eat grains such as wheat, corn or rice, whether it's because of an allergy or an autoimmune disorder.