Well iv started feeding linseed and that alone is 23% protein
Yet I remain onthe fence on this one, generations of keen eyed horsemen have observed an apparent link with protein,rather than sugars.
The trouble is, the 'traditional' protein containing feeds (cereals) also happen to be high in starch as well. So it was noted that cereals caused problems and this was attributed to the protein content, rather than the starch content that 'experts' now believe are the trigger.