Well, think of it this way.
When you do not eat that much, your body fat lowers little by little, but considering that this is a question, I'd say starvation. Think of it as when you fast (Not eating all night say to go to a doctors appointment) your body stores the fatty acids to make ketone! The ketone will build a bloodstream that flows to the brain and other parts of the body!
To sum it up, starvation.
Http://blogs.discovermagazine.com/seriouslyscience/2015/01/29/pandas-ancestors-ditch-meat-bamboo/
According to this study, it may have had to do with the deactivation (technically known as “pseudogenization”) of an umami taste receptor gene. Umami is the taste that makes things like meat, soy sauce, and mushrooms extra yummy. Apparently, at some point in panda evolution, the umami receptor became non-functional. Based on how much the gene has changed, the authors calculate that this happened around the same time that pandas started eating bamboo. Whether it’s cause or effect is unclear, although the authors think the switch to bamboo may have happened before the gene was lost. Regardless, the loss of the gene reinforced the panda’s vegetarian diet because it made meat less delicious to the bears.
Sorry it's a lot but hope it's useful
Answer:
Polar bears consume ringed seals (which are tertiary consumers) as well as fish like trout, salmon, and cod (which are secondary consumers).
Explanation:
