In nature, it is the female Lion known as the Lioness that goes out hunting for the pride's food in packs while the males Lions are the ones that spend most of their time lounging around roaring orders on where to hunt, when to hunt, what to hunt, and of course, how the portions of meat would be divided. Of course the lions who did the least amount of work got the most meat, just because they were the alphas of their respective prides. This had been the case for the previous prides Zira had been with throughout her childhood and early adulthood.
But within Scar's Pride, things are different, he is the king of and arid land that has a scarcity of food, one that can not support the traditional pride structure, most kings would relocate to some other more fertile land, but instead, Scar had the pride adapt. He would personally lead projects to have rivers redirected into his land in the hopes attracting more prey species, this digging work would be handled not by Lions, but by contracted Hyenas, a brilliant move to reduce the pride's workload. These Hyenas would also serve as his bodyguards for several of Scar's reforms were not exactly popular among male lions, especially the one that insisted male Lions would work just as hard in hunting as females.
These radical decrees to adapt to a land of scarcity made Scar the smartest Lion she had ever met, truly deserving of his title of king. Much more so than his brother Mufasa who he had apparently deposed before Zira arrived in the land. It did not take much observing all this for Zira to become one of Scar's most enthusiastic supporters, nor did it take much for Scar to notice her passion.
Becoming Scar's mate was a dream come true to Zira. She never needed to lift a single claw to get food. Instead of catering to a male, she was the one being catered to, even though she was not yet pregnant, Scar always treated her as if she was. Zira was also given portions of meat much larger than she had in previous prides. Zira began to take advantage of this by asking for more meat more often, and every request has been granted.
Yes, he is actually the one catering to her. Making sure she gets as much meat as she wants. And now the results are starting to show on Zira's figure, her belly has taken a shape it has never had before, round.
Such a shape has brought overwhelming joy to Zira, as having a big round belly symbolizes the fact that she now has the highest status among Lionesses in the local pride. Obesity is a status symbol among Lion prides, and as such the fact that she's getting fat, especially in a land of scarce food is powerful status symbol indeed. The fact that Scar also seems quite pleased at the sight of her weight gain is also an added bonus.
One particular day, after a devouring an entire gazelle carcass by herself, Zira feels especially stuffed and bloated, and it shows, as her belly has swollen up large and round enough to be the same size as her head. A content Zira burps, and rubs her bloated belly with her paws, contemplating how best to exploit the status that her newfound obesity is bound to bring her. She is not yet pregnant with his successor, but perhaps this obesity she is growing is the next best thing? Scar seems quite happy with the idea of fattening her up as he is with the idea of mating with her.