Does USDA Database Subtract Fiber?

I just bought my first jicama, so I went to the database to see what
the carb numbers on it are. (Next I'm off to look for recipes. For
taste and texture, I'd say it's about 75% apple and 25% turnip.) For
1/2 cup of raw jicama, it says:

5.73 carbohydrate, by difference
3.2 fiber
.06 fat
.47 protein
25.0 calories

So, multiplying things out, I get:

5.73 x 4 = 22.92
.06 x 9 = .54
.47 x 4 = 1.48
-----------------
Total: 25.34

Close enough for government work. So I'm assuming that 5.73 already
has fiber subtracted, and that's what they mean by "by difference,"
right?

But then I looked in my new Dr. A's Carbohydrate Gram Counter, and it
says:

5.7 total carbs
3.2 fiber
2.5 net carbs
.1 fat
.5 protein
25.0 calories

So Dr. A's chart gives the same amount for total carbs, including
fiber, that the USDA chart gives for "carbohydrate by difference."
But if that includes fiber, then they're both including the fiber
count in the calories, aren't they? I thought the whole point of
doing the math was that the calories never include fiber, so by
subtracting the protein and fat calories from the total, you can see
what calories belong to the net carbs without fiber. Something
doesn't make sense here.



--
Aaron -- 285/235/200 -- aaron.baugher.biz

No, by difference is how that calculate carbs. They take total energy
(calories) and subtract the protein and fat, the carbs are the difference.

Aaron Baugher wrote:
| I just bought my first jicama, so I went to the database to see what
| the carb numbers on it are. (Next I'm off to look for recipes. For
| taste and texture, I'd say it's about 75% apple and 25% turnip.) For
| 1/2 cup of raw jicama, it says:
|
| 5.73 carbohydrate, by difference
| 3.2 fiber
| .06 fat
| .47 protein
| 25.0 calories
|
| So, multiplying things out, I get:
|
| 5.73 x 4 = 22.92
| .06 x 9 = .54
| .47 x 4 = 1.48
| -----------------
| Total: 25.34
|
| Close enough for government work. So I'm assuming that 5.73 already
| has fiber subtracted, and that's what they mean by "by difference,"
| right?
|
| But then I looked in my new Dr. A's Carbohydrate Gram Counter, and it
| says:
|
| 5.7 total carbs
| 3.2 fiber
| 2.5 net carbs
| .1 fat
| .5 protein
| 25.0 calories
|
| So Dr. A's chart gives the same amount for total carbs, including
| fiber, that the USDA chart gives for "carbohydrate by difference."
| But if that includes fiber, then they're both including the fiber
| count in the calories, aren't they? I thought the whole point of
| doing the math was that the calories never include fiber, so by
| subtracting the protein and fat calories from the total, you can see
| what calories belong to the net carbs without fiber. Something
| doesn't make sense here.

On Jul 13, 1:57 pm, Aaron Baugher wrote:

Close enough for government work. So I'm assuming that 5.73 already
has fiber subtracted, and that's what they mean by "by difference,"
right?

No. What they mean is... carbohydrate is never directly calculated.
They find the total calories, test for how much protein and fat,
subtract the calories for the protein and fat, and assume the rest of
the calories are carbohydrate. Thus fiber is NOT subtracted, but part
of the total carbohydrate.

This is opposed to countries where carbohydrate is measured
directly... so their carb counts do NOT include fiber.

"By difference" means they ASSUME how many calories are from
carbohydrate. This is why yogurt carbs as calculated in the US are
wrong... because our calculations assume everything that is not
protein and fat is carb, whereas most of the milk sugar has been
converted to lactic acid... which still has calories, but is not a
carb.

I "count" a cup of whole milk plain yogurt as 4 carbs... and it
"works" by my bg meter to do so.

I thought the whole point of
doing the math was that the calories never include fiber, so by
subtracting the protein and fat calories from the total, you can see
what calories belong to the net carbs without fiber. Something
doesn't make sense here.

The calories DO include fiber. Calories are measured by burning a
food completely... and seeing how much the temperature of water is
raised by the burning. So fiber counts. EVERYTHING counts, even if it
can't be metabolized by humans at all.

This is why high-fiber foods are good for weight loss... because
you're eating a bunch of calories that are metabolically inactive. My
current diet is around 1700 calories per day... but 200 of them are
fiber, so my body only "gets" 1500 calories per day.

writes:

On Jul 13, 1:57 pm, Aaron Baugher wrote:
Close enough for government work. So I'm assuming that 5.73 already
has fiber subtracted, and that's what they mean by "by difference,"
right?

No. What they mean is... carbohydrate is never directly calculated.
They find the total calories, test for how much protein and fat,
subtract the calories for the protein and fat, and assume the rest of
the calories are carbohydrate. Thus fiber is NOT subtracted, but part
of the total carbohydrate.

Ok, so....fiber is included in the total calories, then? I thought it
wasn't. I haven't ever paid all that much attention to labels,
because I stuck to foods low enough in carbs that I didn't have to be
that picky, so I guess I had this wrong all along. So, if you add up
the calories from protein, fat, and all carbs including fiber, you
should get the total calories on the label? Got it.

I "count" a cup of whole milk plain yogurt as 4 carbs... and it
"works" by my bg meter to do so.

That reminds me of something else I was wondering: is there any
do-it-yourself way of determining how many carbs are in something?
Since I make my own yogurt and cream cheese, and I understand that
homemade yogurt tends to be lower in carbs than most store-bought
yogurt, and I'm also planning to try some frozen yogurt soon, I'd
really like to know how much mine actually has. I know Bernstein
talks about using test strips to determine whether something has
usable carbs, but I think that's just a yes/no sort of thing, not a
measurement. Other than eating something and gauging the effect by
the change in your blood sugar, is there any way to test a food
yourself without getting a bomb calorimeter?

The calories DO include fiber. Calories are measured by burning a
food completely... and seeing how much the temperature of water is
raised by the burning. So fiber counts. EVERYTHING counts, even if it
can't be metabolized by humans at all.

I understood that; I guess I just thought they didn't include calories
from fiber in the total because humans can't use them anyway. Thanks
for setting me straight.

This is why high-fiber foods are good for weight loss... because
you're eating a bunch of calories that are metabolically inactive.
My current diet is around 1700 calories per day... but 200 of them
are fiber, so my body only "gets" 1500 calories per day.

Is there any advantage to eating 1700 calories where 200 are fiber, or
just eating 1500 calories without fiber, though, from a diet
perspective? I suppose it means a fuller stomach on fewer calories,
but as far as weight loss goes, is there any reason a fiber calorie is
better than no calorie at all?

I ask because my girlfriend read something about how fiber calories
"attach" themselves to fat and carbs and carry them out of the body;
and supposedly you could subtract one carb gram, one fat, and one
protein from your diet for each fiber gram you ate, or something like
that. I probably don't have the details right, but it sounded odd.



--
Aaron -- 285/235/200 -- aaron.baugher.biz

On Jul 13, 9:24 pm, Aaron Baugher wrote:

That reminds me of something else I was wondering: is there any
do-it-yourself way of determining how many carbs are in something?
Since I make my own yogurt and cream cheese, and I understand that
homemade yogurt tends to be lower in carbs than most store-bought
yogurt, and I'm also planning to try some frozen yogurt soon, I'd
really like to know how much mine actually has. I know Bernstein
talks about using test strips to determine whether something has
usable carbs, but I think that's just a yes/no sort of thing, not a
measurement. Other than eating something and gauging the effect by
the change in your blood sugar, is there any way to test a food
yourself without getting a bomb calorimeter?

As far as I know, you'd need a lab to test for carbs. First you'd
need to break down all the "disaccharides" like sucrose and the
digestible "complex" carbs like starch, and then you'd have to test
for each of the possible monosaccharides. Glucose is not the only
one!

Bernstein's method of using urine test strips only works for glucose -
cause that's what urine test strips test for. And that's why he says
to chew up the food first and spit it out... saliva contains an enzyme
that hydrolyzes starch. Starch would normally give you a negative
result with that test... until it's broken down so there's glucose.
And sucrose wouldn't test positive either, unless you hydrolyzed it
first to obtain glucose.

For a food containing lots of fructose or another monosaccharide
besides glucose, the urine test strips won't work at all.

Basically, the urine test strip as described by Bernstein (with saliva
added) is gonna give you a yes/no to a question like... "Did they add
sucrose to this broth?" or "Is this soup thickened with corn
starch?"

If it were me, I'd assume homemade yogurt had about 4g carb/cup...
same as store-bought.

Cream cheese is trickier as the store-bought stuff has all sorts of
thickeners and such added to it which likely increase the carb count.
If you assumed it had the same amount of carb, that would be a
conservative estimate.

On Jul 13, 9:24 pm, Aaron Baugher wrote:

Is there any advantage to eating 1700 calories where 200 are fiber, or
just eating 1500 calories without fiber, though, from a diet
perspective? I suppose it means a fuller stomach on fewer calories,
but as far as weight loss goes, is there any reason a fiber calorie is
better than no calorie at all?

Probably not if you're eating 200 calories worth of psyllium husks or
such. It'd just run right through you.

But if you're eating lotsa fiber because you eat lotsa fruits and
vegetables, it means you're getting a wide variety of micronutrients.

I don't "aim" to get 50g fiber/day... it just happens cause I eat lots
of fresh produce.

I ask because my girlfriend read something about how fiber calories
"attach" themselves to fat and carbs and carry them out of the body;
and supposedly you could subtract one carb gram, one fat, and one
protein from your diet for each fiber gram you ate, or something like
that. I probably don't have the details right, but it sounded odd.

That sounds rather odd to me too.

I suppose if you ate ENOUGH fiber, it would work like that... just as
some people abuse laxatives to lose weight.

writes:

If it were me, I'd assume homemade yogurt had about 4g carb/cup...
same as store-bought.

Thanks, that seems safe enough. I thought the store-bought kinds were
higher than that, around 10-14, but that's probably because I've never
gotten the real full-fat stuff. I just grab whatever plain kind is on
sale to use as a starter for mine, and that's usually going to be
fat-free.

Cream cheese is trickier as the store-bought stuff has all sorts of
thickeners and such added to it which likely increase the carb count.
If you assumed it had the same amount of carb, that would be a
conservative estimate.

Well, since I make it from yogurt, I suppose I can at least assume it
won't have more carbs than the yogurt did, and probably less, since
some carbs (maybe most) would drain out with the whey. A gallon of
yogurt (16 cups) would have 64g, and I think that turns into about 2
pounds of cream cheese, so a max of 32g/lb, or 2g/oz. I'll have to do
some measuring with the next batch, but it ought to work out to less
than 1g per tablespoon, at most.

I guess if I ever want to go into production and sell my fancy
Low-Carb Yogurt Cream Cheese ("Cures what ails ya!"), I'll have to
send a sample off to a lab for testing. :-)

I guess that would also be the way to find out what different yogurt
cultures are in it, since the more expensive varieties I've seen list
a few different ones on the side, implying that the more cultures, the
better.



--
Aaron -- 285/235/200 -- aaron.baugher.biz

writes:

On Jul 13, 9:24 pm, Aaron Baugher wrote:
Is there any advantage to eating 1700 calories where 200 are fiber,
or just eating 1500 calories without fiber, though, from a diet
perspective? I suppose it means a fuller stomach on fewer
calories, but as far as weight loss goes, is there any reason a
fiber calorie is better than no calorie at all?

Probably not if you're eating 200 calories worth of psyllium husks
or such. It'd just run right through you.

But if you're eating lotsa fiber because you eat lotsa fruits and
vegetables, it means you're getting a wide variety of
micronutrients.

Yeah, I can see that. It's kind of like the issue of "good carbs."
Fiber is often found in the presence of good nutrients, but that
doesn't make it a good nutrient itself. I keep waiting to find some
study that shows fiber *itself* is good for something besides
preventing constipation in people who don't eat enough fat, but I'm
starting to think it doesn't exist. So if I get it incidentally in a
bunch of nutritious foods like you're talking about, that's fine, but
I'm not going to make any special effort to pick particularly
high-fiber ones.



--
Aaron -- 285/235/200 -- aaron.baugher.biz