Sorry to hear about Ozzy's colitis and hope that you manage to get it sorted soon.
Although I wouldn't suggest you do anything other than what your vet tells you to treat the colitis, I do think your visit raises a couple of questions.
Firstly your vet says "dogs need carbohydrates for energy". Grain-free foods are just that. They don't have cereals in them. They do contain around 20% or more carbohydrates usually in the form of potatoes, peas or other vegetables depending on the recipe. So your dog is getting energy from carbohydrates if you feed a grain-free food. However, it's also just not true to say that dogs need carbohydrates for energy. Here's a quotation from an article in The Whole Dog Journal.
Why include carbs?As we mentioned before, dogs have no nutritional requirement for dietary carbohydrates. They can get everything they need from a diet that contains only protein and fat. Energy metabolism in the dog can be based on fat oxidation and the breakdown of protein to produce glucose.
There are two main reasons why we feed carbs to dogs. The first reason is because we can. Dogs can utilize just about anything we feed them; their digestive tracts are extremely versatile. The second reason is economic; fat and protein sources are much more expensive than carbohydrates.The reference to the article if anyone is interested is
http://www.whole-dog-journal.com/issues/13_10/features/Carbohydrate-Intake-For-Dogs_20103-1.htmlI'm sure your vet is perfectly good and has just been a bit sloppy in talking about food but it does make me wonder how much misinformation comes from vets.
Secondly, and this is a bit of a rant topic for me, is Hill's food. Hill's produce lots of niche products that are expensively marketed through vets. However irrespective of the high price, they use a lot of strictly second rate ingredients. I won't do a full analysis of i/d, but if you look at the ingredients:
Hill's i/d
Whole Grain Corn, Brewers Rice, Dried Egg Product, Chicken By-Product Meal, Corn Gluten Meal, Pork Fat (preserved with mixed tocopherols and citric acid), Powdered Cellulose, Lactic Acid, Dicalcium Phosphate, Chicken Liver Flavor, Iodized Salt plus other additives.This is marketed as chicken and rice, and supposed to be better than home-cooked fresh chicken and rice, yet the chicken (fourth ingredient on the list) comes from by-product meal which:
Consists of the dry, ground, rendered, clean parts of the carcass of slaughtered chicken, such as necks, feet, undeveloped eggs, and intestines -- exclusive of feathers except in such amounts as might occur unavoidably in good processing practices. Chicken byproducts are much less expensive and less digestible than the chicken muscle meat.The ingredients of each batch can vary drastically in ingredients (heads, feet, bones etc.) as well as quality, thus the nutritional value is also not consistent. Don't forget that byproducts consist of any parts of the animal OTHER than meat. If there is any use for any part of the animal that brings more profit than selling it as "byproduct", rest assured it will appear in such a product rather than in the "byproduct" dumpster. Even the rice, which you would have thought was cheap enough, is a second rate product known as brewer's rice which is defined as:
The small milled fragments of rice kernels that have been separated from the larger kernels of milled rice.
A processed rice product that is missing many of the nutrients contained in whole ground rice and brown rice. Contrary to what many pet food companies want to make you believe, this is not a high quality ingredient, just much cheaper than whole grain rice. The definitions come from the Dog Food Project - Ingredients to Avoid which also includes corn gluten meal and cellulose (aka dried wood)
You probably didn't want to hear this when concentrating on getting Ozzy well, and I'm sure a short time on Hill's i/d is nor going to cause any problems, but equally I'm sure there are other options of bland foods that the vet could have suggested, and I feel it's important for people to understand the whole picture.
