What the Heck Is low sugar feed for horses?

http://news.thenewsbee.com/story/568549/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 gut comfort, intestinal health and better nutrient absorption. A low-starch fibre-rich formula with natural ingredients to help maintain calm digestion and general wellbeing.