Starch in dog food | Student led inquiry

There is debate as to whether dogs are carnivores or omnivores.  Some foods might be more appropriate than others for the digestive system of canines.  Student Morgan Morris organized a biology laboratory interactive in which he gathered multiple brands of dog food for starch testing.

Note:  This was not a laboratory-grade experiment but simply a survey of starch content utilizing potassium iodide as detection for starch in the dog food samples.  We were looking for a range of black to lighter color gradations, which we believed were visual evidence of differing levels of starch in the dog food.  The visual inspection was quite subjective with no established color scale for comparison utilized.  We performed 6 different trials. It was a loosely controlled experiment; basically a simple inquiry.

Sample #5, and to an intermittent extent, samples #6, #9 and #12, illustrated a “browner” tint as compared to the jet black results on the other samples.  Sample #5 had the most consistent color difference as compared to #6,  #9 and #12.  Approximately 5 out of 6 trials of sample #5 illustrated a markedly color difference from the jet black color of the other samples tested.

We concluded in this brief experiment, that sample #5, and possibly samples #6, #9 and #12 contained less starch.   Student Jeff Collins proposed that the browner samples may have a higher fat content, thus potentially blocking the effectiveness of the iodine starch test.  The brief discussion regarding the results were recorded in the video:  “Starch in dog food | Student led inquiry.”

dog food starch results
Sample #5, and to an intermittent extent, #6, #9 and #12, illustrated a browner tint as compared to the jet black color result on the other samples.

Your thoughts?


Recommended by Morgan:

Dog food comparisons:  Morgan Morris, October 2019.
Dog food comparisons: Morgan Morris, October 2019.

Note:  The numbers in this list do not correlate with the numbers in the experiment we performed.  They also do not indicate order of preference.  They were just meant to showcase “likability” and nutritional aspects of the foods.


Added 9-26-2019

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. The author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

October 18, 2017 Barnes Disclaimer


  1. This experiment should be talked about a lot more. It’s great to know what to feed and not to feed to your dogs. I wouldn’t want to give my pets things that aren’t healthy for them.


  2. I think this should definitely be looked further into ! I would really like to know what would be better to be feeding my dogs.


  3. This was such a cool experiment and it was really informative to hear Morgan explain his thoughts and findings to supervisor Caldwell this past Saturday.


  4. This experiment was very interesting! I have dogs, and wants whats best for them, as for what they eat as well!


    1. I’ve always been a big animal person. I get to do what I love, and excel at doing it. Plus $11 per hour to hang out with dogs never hurts😂

      Liked by 1 person

  5. I feel that this was a fun & unique experiment which involved science & actual “real” life situations. Many people own animals & dearly love them.


  6. This experiment was super interesting to me. I am a “dog mom” and only want the best for my dogs. This made me feel good about what I choose to feed my pups!


  7. Would each piece have the same affect, even if say you broke each piece down and completed the same experiment? would #12 still have the same results?
    Just curious. Great job on the experiment!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s