Q: My vet told me that my four-year-old Miniature Schnauzer is slightly overweight, so she recommended reducing her daily feeding portion by about 15 to 20 percent. Whenever I do, she vomits a yellowish fluid.  She’s currently on a mix of grain- and starch-free kibbles and freeze-dried raw dog food and her daily portion is split into two feedings—once in the morning and once at night. How can I manage her weight while ensuring she isn’t so hungry she vomits bile?

A: Vomiting bile is certainly not a normal sign in any dog, and should not be due to being hungry. It may be worth getting some tests done, as the vomiting could be due to gastric ulcers, unbalanced acidity levels, irritable bowel disease, or a bile or liver issue. It would need further checks by a vet.

It is better to feed her just one type of food, as feeding both the kibble and the freeze-dried raw food may be throwing her gastric acid levels off. I’d suggest feeding her just the raw food only for a month or two—dividing this into two to three meals throughout the day. I also suggest adding two percent of grated vegetable matter to the food, as this will make her feel fuller but won’t add extra calories. 

If the vomiting settles down, then in the long-term feed her just one meal per day in the morning. This allows her to burn calories during the day while she is active instead of going to bed with a full stomach. Her body converts extra blood sugar into fat while she sleeps.

It is also a good idea to make sure she is not around in the kitchen when you are preparing human food, as it may be triggering messages in her system that food is coming for her, causing gastric acid to be released into her empty stomach, leading to vomiting. When the stomach is empty, it is normal to have a yellow tinge to the vomit because there’s bile coming from the small intestine. However, it is not because she is hungry or needs feeding.

If she continues to vomit bile, I would recommend that your vet run some bile acid tests on her, or possibly a barium x-ray to see how she is processing her food.