The energy (caloric) intake of a horse can be visually monitored by watching the weight of the horse. If horses are being fed too many calories (too many groceries) they will begin to gain weight and eventually become fat. On the other hand, horses that are not getting enough calories in the diet will become thin and eventually will not be able to perform, athletically or reproductively.

The amount of energy we need to provide a given horse depends upon the size and activity level of the horse. From a caloric standpoint, activity includes a number of demands such as reproduction, growth, and work (exercise). Horses should have their daily energy requirement provided to them regardless of whether it is summer or winter. In the hot summer months, recent research has shown it beneficial to provide some of the extra calories required by horses as dietary fat.

Because fat (vegetable oil, rice bran, etc.) contains more than twice as many calories per pound as either carbohydrate or protein, a horse eating a fat-supplemented diet will need to eat fewer pounds of total feed. This lower feed intake results in less heat produced during the digestive process and less thermal load. All of these factors combine to keep horses cool and happy during the summer.