It's not just about being overweight, there are at least two other common things to watch out for, before we even think about the heritable metabolic issues such as HYPP and EPSM.
- Hind gut acidosis
- Blood sugar/insulin spikes
As to treats, it is easy to assume that because the overall diet is low in sugar the odd carrot or mint doesn't matter. And for some horses it doesn't. But if you have a sensitive one then you could be causing the blood sugar to spike, which of course has a negative impact on the other side. And of course if the diet is already a bit high in sugar then too many carrots can tip a horse over the edge.
Plus sometimes I think it just isn't fair. For example, my own Grace has to have a very low sugar/starch diet - sugary treats just set up the cravings all over again - it took me many weeks to wean her off sugar, why would I want to put us both through that again?
But I do use treats, but instead of sugary carrots and apples I feed herbs. I try different things with her and she loves to get to choose. Current favourite is lemon balm, but she likes a lot of things and it means she gets variety, low sugar and a positive contribution to her diet.
Herbs are fun!