I would recommend understanding the contents of said diet to better understand that ‘high fat diet’ doesn’t just mean animal fats. There’s soybean oil and pig lard (also higher in linoleic acid than tallow) as the main energy sources.

I’m tired of these crap designed scientific studies lumping all fats as bad sources of energy. Break it down people, test it with and without linoleic acid and seed oils and then show us the results. Repeat this study with a diet of pure tallow for fats and show me the results.