Integrity Lite No Molasses is the lowest starch balanced formula of the Integrity products and is a low sugar formula. You can add calories for weight gain by top dressing the Integrity Lite with Integrity Rice Bran or oil. Rice bran has more starch than oil, which is 99.9% fat.
You may want to consider feeding a different hay that is lower in starch, such as timothy or Bermuda. My forage feeding recommendations include that not more than 50% of the forage fed can be alfalfa and not more than 50% of the hay can be processed hay (pellets or cubes).