Just wondering what the body does with far and how it handles it without carbs/insulin. Also would it make a difference if this fat was ingested after a 20 hour fast? Or if ingested with protein?
Fat is a triglyceride molecule composed of a glycerol backbone to which three fatty acids are attached.
Once dietary fat is digested its broken into free fatty acids and the glycerol is metabolised.
For fat to be stored the three free fatty acids must be esterified to the glycerol. This means that without glycerol you can't store fat.
Glycerol is converted into glucose and cant be reused, it can only be synthesized but if you're on a low carb diet theres little glucose to synthesize it from.
Hence its the glycerol that's the limiting factor in adipogenesis (i.e. abdominal fat synthesis) during a low carb diet rather than the insulin.
Yes, you can store fat with out having high insulin. See: Acylation Stimulating Protein
That said, as I understand it ASP is a bit more....passive. It will load fat into fat cells but doesn't interfere with fat leaving the fat cells.
Of course you can. Fat has an extremely high storage percentage and isn't a costly process like it is to turn starch into fat. And even a ketogenic dieter is still producing insulin so if you more than you burn then it's going straight to your hips and thighs. I gained about 10 pounds of fat thinking that you can't get fat on a ketogenic diet. A bunch of unslightly flab around the abdomen brought me back to reality and put an end to my heavy cream-a-thon that I was enjoying.
Mostly this is a non-issue since people in ketosis don't get as hungry and thus it is easy to maintain a calorie deficit. Theoretically, you can store fat on a ketogenic diet, but I suspect you'd be uncomfortable. Dave Asprey claims to have maintained or lost weight eating something like 4000 calories, no exercise, and 5 hours of sleep. He brings a lot of neolithic technology to bear on himself though. For him, the paleo diet is just a starting point from which to start biohacking. During a fast, you are burning fat. Eating fat means the body can stop using its own stores and burn what you just put in. This will make the body happy and it will stop worrying about conserving fuel to keep you alive. Some proteins are more insulinogenic that others, but proteins in general will raise insulin. So, if you eat milk proteins, insulin will go up, and the fat will probably get stored. Or if you eat a large amount of proper paleo protein, a similar thing could happen.
Don't worry about this too much though. What gets stored also gets burned, and since there isn't excess glucose around to burn, fat stores start getting burned as soon as the transient condition causing fat storage is over.
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