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Closeup of a Black Dog

What do dogs choose to eat, if they have a choice??

STUDY:  Roberts MT, Bermingham EN, Cave NJ, Young W, McKenzie CM & Thomas DG 2018, ‘Macronutrient intake of dogs, self-selecting diets varying in composition offered ad libitum’, Journal of Animal Physiology & Animal Nutrition (Berlin), vol. 102, no. 2, pp. 568-575. doi: 10.1111/jpn.12794.

Aim: determine the macronutrient self-selection in dogs fed over 10 days.



15 adult dogs were given access to three wet diets providing 500% of daily ME, twice daily over 10 days.

The diets were nutritionally complete and formulated using the same four ingredients in different proportions to supply high levels of protein (58% ME), fat (86% ME) or carbohydrate (54% ME).



  • when dogs are allowed to self-select from diets varying in macronutrient composition, they will consume at least 30% of their energy from protein.

  • Protein intake increased from 29% total energy on day 1 to 44% by day 10.  

  • This increase in protein intake was associated with a decrease in fat consumption over the experiment, with the dogs consuming 68% on day 1 and 52% by day 10. Thus, the protein:fat ratio increased from 0.45 on day 1 to 0.90 by day 10.

  • Carbohydrate consumption remained steady at 3% throughout the study.


Relevance: dogs still possess a "feast or famine" mentality, wherein energy dense fat is prioritised over protein initially. With continued feeding over 10 days, a transition to a more balanced energy contribution from both macronutrients is evident. The study also shows that given the option, dogs do not select carbohydrate to be a significant portion of the diet. The health implications of such dietary selection are of interest.

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