On July 2nd, Hannah Godfrey successfully defended her PhD titled, ”Dietary macronutrients in feline health and metabolism”.
Read on for more information about Hannah and her thesis!
Overview of Thesis:
Cat obesity is a major health and welfare concern that affects, not only our pets, but their owners and vets as well. It has been thought that consuming too much dietary carbohydrates might cause cats to gain weight, but the research is conflicting. Therefore, we looked at how different nutrients, specifically protein, fat, and carbohydrates, can affect cat health. First, a meta-analysis was conducted to review past studies to determine if a link between carbohydrate content in cat foods and parameters of feline obesity exists. We found that in cat foods containing between 2.8% to 57% calories from carbohydrates did not lead to more body fat or higher blood sugar or insulin levels. The results of the meta-analysis, published in the Journal of Animal Science are also summarized in our blog post titled, “New Publication! A meta-analysis: Dietary carbohydrates do not increase body fat or fasted insulin and glucose in cats”.
Following these findings, we tested how diets that were low in protein, fat, or carbohydrates, could benefit energy use, body fat, activity levels, hunger hormones, insulin and glucose, and heart health. Interestingly, we found that cats utilize dietary energy sources in response to their intake (so when they consumed more carbohydrates, they were able to adjust and utilize those carbohydrates for energy over other sources such as protein).
You can read more about this finding in our blog post titled, “New Publication: Isoenergetic reduction of dietary macronutrients modulates respiratory quotients and heat increment of feeding but not energy expenditure in cats“.
In addition, we found that a diet low in fat was beneficial in promoting greater muscle mass. However, the low-carbohydrate diet was more suited to promoting satiety. More information on these findings can be found in our previous blog post titled “New Publication: Isoenergetic reduction of dietary macronutrients affects body composition, physical activity, and post-prandial hormone responses in lean and obese cats fed to maintain body weight“.
As expected, diet did not appear to affect the blood glucose concentrations in the cats. That said, insulin secretion appeared to be most affected by the level of protein in the diet. This makes sense given the obligate carnivore nature of cats and thus, their reliance on amino acids (from protein) for insulin secretion. Surprisingly, we also found that a low carbohydrate diet may have been the most beneficial for cardiac function; however, more research is needed over a longer time frame.
Overall, the findings suggest that carbohydrates do not pose a significant risk for obesity. A balance of macronutrients, including fats and proteins, plays a crucial role in maintaining lean body mass and overall health.
What’s Next for Me?
I look forward to continuing my journey in research and academia as I complete a 1-year post-doctoral position here at the University of Guelph where I will continue with work related to both canine and feline nutrition. Additionally, I will keep one foot in the industry side by serving on the R&D board for a Canadian pet food company where I can utilize the knowledge gained and implement into products for our pets!
What was a research challenge you had to overcome?
Research is not easy, and working with live animals adds an additional challenge. I am beyond grateful for the opportunity to work with such wonderful creatures though I would be lying if I said they didn’t cause additional challenges. Cats, as cute as they are, do not always respond the way you think they will or even want them to. This was definitely an aspect of the research that posed some challenges but of course, was a net positive experience.
Please share some information about your furry lab assistants.
My pets are the reason I do what I do! Say hello to Buckets and Midna, my two kitties and to Oakley, my sweet pup! Buckets is a retired academic – he contributed to multiple research studies and was even part of my MSc. work! Midna is a sweet and timid little girly who loves naps in her cat tree.
Oakley is a complete menace and I wouldn’t have him any other way!
Funding statement
Hannah’s PhD research was supported by the Joint NSERC Alliance and Mitacs Accelerate program in partnership with Champion Petfoods. We thank you for your contributions.
I also want to note my appreciation and thanks to the multiple scholarship opportunities I was successful in, including the Ontario Graduate Scholarship and the multiple Ontario Veterinary College Internal Awards I received.