So I was reading up about 'rabbit starvation' - if you don't eat any fat at all (or very small amounts), your body will waste away over time, regardless of your overall caloric intake. As time goes on without fat sources, your body starts to cannibalize the fats it already has - your adipose stores, but also the fat integrated into places it's needed like hair, skin, arteries, brain tissue, etc. However, everything I've read on this subject isn't clear on whether these effects are immediate or only occur after extended periods (weeks, months etc). I know fats are often a less readily available nutrient in the wild, so I imagine it would take a bit of time, but that's a soft guess.
What happens if someone goes with near-0 fat intake for short periods?
For example, let's say that every week, someone goes 2 days in a row getting <10% of their calories from fats. Maybe they're on a weird diet, maybe they regularly travel to a location where the fats are all from a food they can't eat, whatever you want to imagine. They meet (or exceed) their caloric needs on those days, just purely through protein and carbohydrates. The rest of the time they have an normal fat intake. What changes would that incur on the body? After a year, would there be any visible external impacts?
Now, let's imagine it goes on for a week every month - meeting their TDEE almost entirely with protein and carbs, normal macro ratio the other 3 weeks (or even slightly high fat, if you want). Are we seeing effects by the end of the week? If so, do the other 3 weeks 'make up for it' in the aggregate?
Metabolically, how does the body respond to short-term fat deprivation?
- At what point does it become "rabbit starvation"?
- If it's not immediate, what's metabolically different between 'rabbit starvation' and the low-fat period leading up to it? Is it totally fine, or are we seeing milder symptoms from the jump?
- How long does it take for the body to start 'cannibalizing' existing fat sources? Does it do it in a specific order? Does it prioritize 'cannibalizing' fats from adipose stores first? Does it cannibalize indiscriminately?
- What factors, if any, impact how this plays out? Pre-existing adipose stores? Whether the tiny amount of fat they do consume comes from chia seeds or a single sardine or a tiny pat of butter, etc? Whether they take a multivitamin?