I’m not sure that there are many options below 325 kcal/cup. Would you consider a canned food? Wet foods usually contain less calories per volume and the extra water is helpful for digestion. He may benefit from a little extra fiber mixed with it- and for that my go to is a small sprinkle of ground physillium husk. The other recommendation that will really balance his tummy would be a probiotic which also contains digestive enzymes. I use HerbSmith- Microflora Plus- it also has stomach calming herbs like ginger and licorice. My dogs love it.
I’m happy to do a complimentary basic consult if you would like 🙂 (https://journeysmobilevet.com/nutritional-consult-options)
