Where does the "extra" fat go?

[Scott]

Long-time follower of the Protein Power plan, but first time on the website. I have always had a question since reading the Protein Power Life Plan. In the book, in the section about how much fact you should eat, they make the statement that fats must be controlled during weight loss to induce a caloric deficit, but after achieving the desired weight, you can eat all you want. So...if I am at my desired weight and eat a thousand more calories a day than I need for my energy expenditure, how does the body get rid of the excess? I am picturing fat molecules floating around my bloodstream, passing by cells that are already "full." With no insulin to force these cells to take in more fuel, I assume that the fat just floats around until excreted in the urine. Is this correct? Does the body handle excess protein the same way?

Thanks.

[Relief]

I don't think it comes out in the urine--maybe in the stool? But I don't bellieve that you CAN over eat day in and day out and not gain, even when controlling carbs. Perhaps when the lo carb gurus say you can eat ALL YOU WANT, they are pre-suppossing that your appetite will stop you appropriately.

well...Maybe and maybe not--I have to watch protions of high fat foods--even at goal weight, even when consuming less that 40 carbs a day--or I will gain. others on this board have had the same experience

[Gaelen]

Excess protein would be excreted in the urine; excess fat wpuld be excreted in/with stool.

[mcsblues]

Excess protein would be excreted in the urine; excess fat wpuld be excreted in/with stool.
Ooooh! ... fighting words!:lol:

Seriously though, as I understand it we 'lose' some fat, protein and carbs (yes!) in our faeces ... umm ... every day! Yes the % in urine and faeces may change, but either way, as Relief says, many of us have found, regardless of how low you keep carbs on maintenance that is not a green light to overindulge in fat and/or protein and see all the 'excess' discarded rather than being stored (mostly) as fat.

I linked to this paper .. umm somewhere else! - which has a charming ;) and detailed 'look' at faecal loss for subjects consuming excess energy on a high fat (31% carb) or a high carb (78% carb) diet. Although the low carb diet wasn't low by our standards, its interesting to see the marked differences in what was 'lost' but also that these losses made no significant difference to the weight gain experienced on both diets.

Effects of isoenergetic overfeeding of either carbohydrate or fat
in young men (http://www.ingentaconnect.com/content/cabi/bjn/2000/00000084/00000002/art00014)

Oh, and welcome aboard Scott!

[Scott]

Thanks for the feedback, but I am still left with a question. Don't want to get too graphic, but...

Most of the protein and fat end up in the bloodstream after digestion, right? Some never makes it to the blood (gets excreted undigested) but most does.

I know how kidneys filter out compounds in the blood. But how does a compound of any sort, fat or anything else, get from the bloodstream BACK into the intestine or colon? I don't think things flow that way, but I'm not a doctor.

It would seem that even extra, unneeded fat would have to be excreted in the urine.

I don't mean to belabor this, but when I am camping I eat home-made pemmican, which is very high fat, sometimes for a couple weeks at a time. During this time I am not expending much energy and I know my intake is in the thousands of calories per day. I don't gain anything. Maybe that makes me lucky from a physiology standpoint, but I still want to understand the mechanism...in other words, where does the extra fat go if it is not going into MY fat?

Scott

[LisaS]

cholesterol goes into the liver -- into the gall bladder and then out into the intestines when it leaves the body.

I don't know that excess dietary fat leaves in the same manner - can try to find out though.

[Gaelen]

Maybe some macronutrient digestion 101 will help... ;)
This paper comes from the National Institutes of Health (NIH) and the National Institute of Diabetes and Digestive and Kidney Diseases:
http://www.nutristrategy.com/digestion.htm

[Scott]

Thanks for the links/resources. Heading off (with my pemmican!) for a week of whitewater rafting with my boy scout troop, so will study the papers when I get back. It's great to have a resource to turn to with questions.

Scott

[LisaS]

maybe I misunderstood the question. I thought we were assuming all the fat ingested was absorbed - and then if it was in excess of needs but not stored how did it leave the body again?

[Gaelen]

LisaS, I think you had the question correct. At least, that's how I understood it, so if you misinterpreted it, so did I. ;)

I just posted the digestion 101 link to refresh people's brains on the basics of digestion. Excretion of excess fat intake also gets into some heavy duty circulatory system 101, but I haven't found a sufficiently descriptive non-technical link to describe that...yet.

[Reverie]

Thanks for that link, Gaelen.

I have a related question about fat. My question is how is dietary fat stored as fat? I thought from PPLP that insulin is the fat storage hormone. It escorts glucose into cells. The excess glucose is stored as fat. But I thought that insulin is not involved with dietary fat.

So is there a specific hormone involved with removing dietary fat from the blood and storing in a "fat storage depot"?

Can specific fat cells be analyzed to see if they were originally from fat or glucose?

[MeDieViL]

i dont think you can store any fat without insulin, this has been proven by someone that eats huge ammounts but does not eat any carbs, for 48 years :p

[Inez]

I'm guessing some of it also just gets burned off as body heat. I've noticed that if I have a really high-fat meal (bacon & eggs cooked in cream and butter, heavy cream in my coffee) even on a cold morning I'm uncomfortably hot a short while after eating.

[Reverie]

Actually, I got out PPLP and they say that if you are not losing weight, you are probably eating too much fat.

I also searched the interet on fat metabolism and they say that fat gets get oxidised immediately and used primarily by muscle (never the brain, it needs glucose) for fuel. The excess gets turned into triglycerides and stored as body fat.

http://www.unisanet.unisa.edu.au/08366/h&p2fat.htm

And regarding testing fat tissue to see where it came from, Dr. Mary Enig says the most prominent fatty acid is monounsaturated, which is olive and canola oils and nuts. They use a blended oil of 1/3 olive oil, 1/3 sesame oil and 1/3 coconut oil.

So the bottom line for me is that I need to limit my fats if I want to keep losing about 2 pounds a week! And also make sure I'm exercising my muscles to burn the fat that I eat.