What the Heck Is grain free feed for horses UK?

http://www.downsouthnews.com/news/story/603272/with-half-of-britains-horses-overweight-bifid-launches-grainfree-lowsugar-feed-for-the-nations-gooddoers.html

Gentle horse feed for sensitive stomachs, designed to support digestive comfort, hindgut health and better nutrient absorption. A low sugar fibre-rich formula with natural components to help maintain steady digestion and overall health.