No oats

and long trotting really helps with getting that extra pudge off. The cantering will 'condition' the horse aerobically, but the trotting will help drop those few extra pounds

Hope that helps.....also try to restrict their feed a little, if they're munching free choice hay or pasture all day long and not getting ridden up into a hard sweat, they don't need it, try penning them up for a few hours a day, just to reduce their fuel consumption.....best of luck