Biniu - a czy przypadkiem na diecie keto nie jest latwiej spalic sam tluszcz ?
WPIER I TAK (JAK W KADZYM SPOSOBIE ODZYWIANIA, SPALANE SA KALORIE POCHODZACE Z ZEWNETRZYNYCH ZRODEL I JESLI ILOSCI TLUSZCZU WCHODZACEGO BEDZIE WIEKSZA NIZ ZAPOTRZEBOWANIE ENERGETYCZNE TO MIMO TO ZE JESTES W KETOZIE I TAK NIE SPALISZ WLASNEGO TLUSZCZU
Zazwyczaj w przypadku diety redukcyjnych nie-keto (dokladnie wysokoww) spadek miesni jest wiekszy w stosunku do spadku na diecie keto.
A TO ZALEZY OD ILOSCI KALORII, JESLI ILOSC BEDZIE NIEWIELKA I TAK ZOSTANA MIESNIE ZUZYTE JAKO
ZRODLO GLUKOZY
Kiedys czytalem o badaniach przeprowadzonych na dosyc sporej grupie osob - na rozych dietach - a tym ze wlasnie na dietach keto oraz niskoww - organizm spalal najwiecej SAMEGO tluszczu. Ilosc spadajacej wagi byla na porownywalnym poziomie. Badanie obejmowalo 4 grupy osob w ktorej wyszczegolniono takze bodazje 4 podgrupy( osoby niecwiczace, cwiczace tylko silowo, cwiczace aerobowo, cwiczace silowo i aerobowo).
Przy diecie keto oraz cwiczeniach silowych i aerobowych spadek SAMEGO tluszczu nie byl najwiekszy - ale mial najlepszy stosunek redukcji tluszcz/miesnie (dieta keto - miala 2 miejsce jesli chodzi o spalanie tluszczu). Badanie bylo przeprowadzone przez okolo 4tyg. o ile mnie pamiec nie myli.
Ale nie pros o linka bo na pewno go nie znajde. Wiem tylko ze o takim badaniu czytalem.
OD LYLE
> True, but yet they reduce body fat on most people why try them. In fact,
> the study showed that low-carbers lost *twice as much* weight as the
> low-fatters.
Extra WEIGHT loss is standard on lowcarb diets due to increased water
losses. This can be very significant (water losses ranging from 1-15
lbs have been reported in the literature).
The question is whether increased amounts of true tissue (fat or muscle)
are being lost. See below for more comments on that.
> Hey, I'm not saying low-carbing is for you. But it seems like
> you are saying that LC eating doesn't work, and the study shows they do in
> fact work twice as well as low-fat diets, and the majority of experiences
> reported here back up the study.
Except that this study runs contrary to just about every other one done
on the topic showing little to no true differences in tissue
(fat/muscle, NOT water) losses between diets.
It *sounds* like they were relying on self-reported caloric intakes and,
if so, the study is fundamentally flawed because study after study shows
that people don't estimate their true caloric intakes worth a shit.
When you consider that controlled calorie studies comparing diets (i.e.
folks are given a meticulously measured number of calories of differing
macronutrient composition) show basically no difference in true tissue
losses, I suspect this is where the problem lays.
...................
Let me explain in simpler words since your reading comprehension seems
to be limited.
In a typical comparison study of a keto vs. non-keto diet (at identical
calorie levels), you might see something like
Keto: 12 lbs lost
Non-keto: 8 lbs lost
Both groups will have lost roughly 8 lbs of true tisseu (being some
combination of fat and lean body mass).
The keto group lost an additional 4 lbs of water.
Understand, NOWHERE did I imply that ALL of the weight loss on a keto
diet is water, that would be absurd. I said that the EXTRA weight loss
on a keto is from water losses. Of course there are true tissue losses
(fat and muscle in some proportion depending on a host of variables) but
there is an EXTRA weight loss on a keto diet that is due to water.
See for examples
Golay A et al. Weight-loss with low or high carbohydrate diet? Int J
Obes (1996) 20: 1067-1072 ;
Alford BB et. al. The effects of variations in carbohydrate, protein and
fat content of the diet upon weight loss, blood values, and nutrient
intake of adult women. J Am Diet Assoc (1990) 90: 534-540.
Both studies compared keto to non-keto diets at identical calorie levels
and found no significant difference in true tissue weight. Total true
tissue weight loss scaled with caloric intake.
.....................
But the fact that people EAT LESS on a keto diet is WHY they lose
weight; it's still a calorie issue.
That's the whole issue at stake: at an identical calorie level will
someone on a keto diet lose more tissue wight (again NOT water weight
which makes up a PORTION of the total weight loss and I'm trying to
emphasize the key words so yo'ull understand waht I'm saying this time)
than someone on a non-keto diet? The majority of the studies say no,
this is one of the very very few that say yes (the Young et. al study
done in the 80's found similar results but had a huge number of
methodological problems).
..........................
Basically, to put it simply, there are two issues at stake here and
you're confusing them.
1. Does a keto diet have some inherent metabolic advantage: to whit, at
an identical calorie level, will a keto diet show greater tissue (fat
and muscle NOT water) losses than a non-keto diet. The studies done
where calories are strictly controlled do not support this (the early
studies confused excess water losses with fat loss)? This study runs
contrary to them suggesting nearly twice as much fat lost at an
identical calorie level compared to the non-keto.
2. Does a keto diet make it easier for people to reduce calories (or
does it cause them to spontaneously reduce calories) so that they eat
less and lose weight.
The answer to #1 is generally no. The grand majority of studies show no
difference (or so small as to be insignificant): given an identical
caloric intake, people lose the same amount of true weight (fat/muscle)
on a keto vs. non-keto diet. This presumes such things as not taking
calories too low and providing sufficient protein. ASSuming those two
criteria are met, differences in true tissue loss (again for hte slow,
fat and protein) are insignificant.
The answer to #2 is yes for many people. The reasons are many. IN the
70's, Yudkin pointed out that, when a given food (carbs) make up ~50% of
total food intake, removing it entirely can not help but reduce total
food intake. Most studies of ad lib food intake on keto diets show that
when people reduce carbs, their protein and fat intakes tend to stay
roughly the same; end results is that total caloric intake goes way down
(1400-1800 calories is fairly typical). In addition, for
hyperinsuleminc folks, removing carbs (or even moderating their intake)
tends to control blood glucose, energy levels and appetite which *may*
make it easier to reduce total caloric intake.
Does this makes sense to you now, we're dealing with two different
issues. I'm talking about #1 and you're making points about #2.
.......................
Lyle
***
Section 4: Water and weight loss
Having discussed the topic of nitrogen sparing we can finally examine
the effects of ketogenic diets on the other aspects of body composition:
water, weight and fat loss. The question then to be answered is whether
a ketogenic diet will cause more weight and/or fat loss than a
non-ketogenic diet with the same calories. As with the sections on
protein sparing, study methodology makes makes it impossible to
absolutely answer this question. Prior to discussing the effects of the
ketogenic diet on body composition, a few comments about the various
studies cited by both the pro- and anti-ketogenic groups are in order.
Problems with the studies
Most of the early ketogenic diet studies looked at weight loss only,
making no distinction between fat, water and muscle loss. As discussed
in chapter 8, a dieter’s goal should be maximal fat loss with minimal
muscle loss. Since water weight can be gained or lost quickly, it
should not be used as the factor to determine whether a ketogenic or
balanced diet is the optimal approach.
Likewise, many early studies, which are frequently cited by
pro-ketogenic authors, confused water loss with fat loss due to
methodological problems. These studies should not be considered as
evidence either for or against a ketogenic diet.
Many early diet studies were extremely short in duration, five to ten
days in some cases. This makes drawing valid conclusions about the
effectiveness of a given diet approach impossible as results are
confounded by the rapid water losses which occurs in the first few days.
In very short term studies, a ketogenic diet will almost always show
greater weight loss because of fluid losses. However, the amount of fat
loss which can occur in this period of time is negligible in almost any
diet study. As well, since few dieters pursue fat loss for only 10
days, studies of this duration have limited applicability.
The early studies
A number of studies done in the 50’s and 60’s showed almost magical
results from low-carbohydrate, high-fat diets. The primary result was
significantly greater weight loss for low versus high carbohydrate diets
in obese subjects (29,30). This led researchers involved to conclude
that there was an enhancement of metabolism with the high fat diets, a
sentiment echoed by some popular diet book authors. It was suggested
that ketogenic diets caused the secretion of a ‘fat mobilizing
substance’ which enhanced fat loss (31,32), but this substance was never identified.
In these studies, obese subjects lost weight on a 2600 calorie high fat
diet but lost no weight when put on a 2000 calorie higher carbohydrate
diet (29,30). As these studies attempted to measure changes in lean
body mass as well, they concluded that large amounts of fat were being
lost on the high fat, but not the high-carbohydrate diets.
As would be expected, results of this nature were far too good to be
true. The very short term nature of the studies, 9 days or less, as
well as the rapid weight loss which occurred in the first few days of
the high fat diets, indicate that the supposed fat loss which was
occurring was coming primarily from changes in water balance (33,34),
which can contribute anywhere from 5 to 15 lbs of weight loss within a
few days (see next section). Later studies using the same experimental
design, determined that the weight lost and counted as fat was water and
that there was no ‘metabolic advantage’ to low carbohydrate diets in
terms of weight loss (35,36).
Water loss on the ketogenic diet
A well established fact is that low-carbohydrate diets tend to cause a
rapid loss of water in the first few days. This occurs for several
reasons. First and foremost, glycogen is stored along with water in a
ratio of three grams of water for every gram of stored carbohydrate
(37). As glycogen is depleted, water is lost. For large individuals,
this can represent a lot of weight.
Additionally, ketones appear to have a diuretic effect themselves
causing the excretion of water and electrolytes (38). This includes the
excretion of sodium, which itself causes water retention. Electrolyte
excretion is discussed in greater detail in the next chapter.
Due to confusions about weight loss and fat loss (see chapter 8), many
individuals are drawn to low-carbohydrate diets specifically for the
rapid initial loss of water weight. During the first few days of a
ketogenic diet, water loss has been measured from 4.5 to 15 lbs (17,39-41).
Although transient, this rapid initial weight loss can provide
psychological incentive for dieters, which may mean greater compliance
with the diet. In one study of subjects on a very-low-calorie ketogenic
diet adhered to their diet much more than individuals consuming more
carbohydrate, and who lost less weight (8).
Regardless of possible psychological benefits, it should be understood
that the initial weight loss on a ketogenic diet is water. This is
especially critical for when individuals come off of a ketogenic diet,
either deliberately or because they ‘cheated’. The rapid weight gain
which occurs when carbohydrates are reintroduced into the diet, which
can range from three to five pounds in one day, can be as
psychologically devastating to dieters as the initial weight loss was
beneficial. In the same way that fat cannot be lost extremely rapidly,
it is physiologically impossible to gain three to five pounds of true
bodyfat in one day. This is discussed in more detail in chapter 14 .
A final thing to note is that this water loss can be misinterpreted as
a loss of protein-containing lean body mass (LBM), depending on the
method of measurement. (8). This may be part of the reason that some
studies find report a greater loss of LBM for ketogenic versus
non-ketogenic diets.
Weight loss
The fact that the initial weight loss on a ketogenic diet is from a
loss of water weight has led to a popular belief that the only weight
lost on a ketogenic diet is from water, an attitude that makes little
sense. The question then is whether more or less true weight (i.e.
non-water) is lost on a ketogenic diet versus a non-ketogenic diet.
In most studies, a low-carbohydrate diet will show a greater total
weight loss than a high-carbohydrate (8,18,19,25,26,35) but this is not
always the case (10,13,15,22) . Once water loss has been taken into
account, the rate of weight loss seen, as well as the total weight loss
is generally the same for ketogenic versus non-ketogenic diets (35,40).
That is, if individuals are put on a 1200 calorie per day diet, they
will lose roughly the same amount of ‘true’ weight (not including water)
regardless of the composition of the diet. As discussed in chapter 2, a
loss of weight is not the sole goal of a diet. Rather the goal is
maximization of fat loss with a minimization of muscle loss.
Section 5: Fat loss
The basic premise of the ketogenic diet is that, by shifting the
metabolism towards fat use and away from glucose use, more fat and less
protein is lost for a given caloric deficit. Given the same total
weight loss, the diet which has the best nitrogen balance will have the
greatest fat loss. Unfortunately a lack of well done studies (for
reasons discussed previously) make this premise difficult to support.
Before discussing the studies on ketogenic diets, a related approach,
called the protein sparing modified fast (PSMF) is discussed. Following
that, changes in body composition are discussed at three calorie levels:
maintenance calories, below 1200 calories per day, and finally between
10% below maintenance and 1200 calories per day.
The PSMF
The PSMF is a ketogenic regimen designed to maximize fat loss while
minimizing protein losses. The sole source of calories are lean
proteins which provide 1.5 grams of protein per kilogram of ideal body
mass (which is used to estimate lean body mass) or approximately 0.7-0.8
grams of protein per pound. (14,20,42-44). Vitamins and minerals are
given to avoid the problems discussed in chapter 7 and no other calories
are consumed (42,44).
The total caloric intake of the PSMF is extremely low, generally
600-800 calories per day or less. Once the adaptations to ketosis have
occurred, the remainder of the day’s caloric requirements are derived
from bodyfat. For an average size male, with a basal metabolic rate of
2700 calories per day, this may represent 2500 calories or 280 grams of
fat (approximately 0.7 lb of fat) used per day.
Fat losses of 0.2 kilograms/day (0.45 lbs) in women and 0.3
kilograms/day (0.66 lbs) in men can be achieved and weight losses of
three to five pounds per week are not uncommon (44,45). This can be
achieved with only small losses of protein, which occur primarily during
the first three weeks while the adaptations to ketosis are occurring.
Additionally, appetite tends to be blunted in some individuals, making
adherence easier. Finally, there are typically improvements in blood
pressure, blood glucose, and blood lipids while on the PSMF (44). These
effects make the PSMF is a very attractive approach for fat loss.
However, the PSMF has drawbacks which make it unsuitable for
do-it-yourself dieters. First and foremost, the extremely low calorie
nature of the PSMF makes medical supervision an absolute requirement as
frequent blood tests must be performed to watch for signs of metabolic
abnormalities (44). Additionally, the excessively low calories will
cause a decrease in metabolic rate making weight regain more likely than
if a more moderate approach is used.
Typically the PSMF is only used with cases of morbid obesity, when the
risks associated with the PSMF are lower than the risks associated with
remaining severely obese, and where rapid weight loss is required
(44,45). In fact, the PSMF has been shown to be more effective in
individuals who are obese versus those who are lean (43,46).
The ketogenic diet at maintenance calories
A popular belief states that fat can be lost on a ketogenic diet
without the creation of a caloric deficit. This implies that there is
an inherent ‘calorie deficit’, or some sort of metabolic enhancement
from the state of ketosis that causes fat to be lost without restriction
of calories. There are several mechanisms that might create such an
inherent caloric deficit.
The loss of ketones in the urine and breath represents one mechanism by
which calories are wasted. However, even maximal excretion of ketones
only amounts to 100 calories per day (47). This would amount to
slightly less than one pound of extra fat lost per month.
Additionally since ketones have fewer calories per gram (4.5 cal/gram)
compared to free fatty acids (9 cal/gram), it has been suggested that
more fat is used to provide the same energy to the body. To provide 45
calories to the body would require 10 grams of ketones, requiring the
breakdown of 10 grams of free fatty acids in the liver, versus only 5
grams of free fatty acids if they are used directly. Therefore an
additional 5 grams of FFA would be ‘wasted’ to generate ketones.
However, this wastage would only occur during the first few weeks of a
ketogenic diet when tissues other than the brain are deriving a large
portion of their energy from ketones. After this point, the only tissue
which derives a significant amount of energy from ketones is the brain.
Since ketones at 4.5 calories/gram are replacing glucose at 4
calories/gram, it is hard to see how this would result in a
substantially greater fat loss. Anecdotally, many individuals do report
that the greatest fat loss on a ketogenic diet occurs during the first
few weeks of the diet, but this pattern is not found in research.
Only one study has examined a long term ketogenic diet at maintenance
calories (17). Elite cyclists were studied while they maintained their
training. Over the span of four weeks there was a small weight loss,
approximately 2.5 kilograms (~5lbs) which was quickly gained back when
carbohydrates were refed. This loss most likely represented water and
glycogen loss, and not true fat loss. Whether this would be different
with weight training is unknown. But it does not appear that a
ketogenic diet affects metabolism such that fat can be lost without the
creation of a caloric deficit.
Strangely, some individuals have reported that they can over consume
calories on a ketogenic diet without gaining as much fat as would be
expected. While this seems to contradict basic thermodynamics, it may
be that the excess dietary fat is excreted as excess ketones rather than
being stored. Frequently these individuals note that urinary ketone
levels as measured by Ketostix (tm) are much deeper when they over
consume calories. Obviously at some point a threshold is reached where
fat consumption is higher than utilization, and fat will be stored.
One study has examined the effect of increasing amounts of dietary fat
while on a low-carbohydrate diet and found that up to 600 grams of fat
per day could be consumed before weight gain began to occur (48). This
effect only occurred in subjects given corn oil, which is high in
essential fatty acids, but did not occur in subjects given olive oil,
which is not. The corn oil subjects reported a feeling of warmth,
suggesting increased caloric expenditure which generated heat. This
obviously deserves further research.
The ketogenic diet at very low calorie levels (VLCD, below 1200 cal/day)
As with the studies on protein sparing, VLCD studies comparing
ketogenic to non-ketogenic diets tend to be highly variable in terms of
results. Some studies show greater weight/fat and less protein losses
(19,24,46,49) while others show the opposite (10,15,21,23,25,26,50).
The variability is probably related to factors discussed previously:
short study periods, insufficient protein in many studies, and
exceedingly low calorie levels.
Additionally, few studies incorporate exercise, which has been shown to
improve fat loss while sparing muscle loss. Therefore, it is difficult
to extrapolate from these studies to the types of ketogenic diets
discussed in this book (with a moderate caloric deficit, sufficient
protein, and exercise). Ultimately these studies should should not be
used as evidence for or against ketogenic diets.
The ketogenic diet at low calorie levels (10% below maintenance to 1200 cal/day)
In contrast to the results seen with ketogenic VLCDs, there is slightly
more evidence that a ketogenic diet will show greater fat loss and less
muscle loss than a non-ketogenic diet at higher calorie levels.
However, more research is needed at moderate caloric deficits. Since
there are few studies done comparing fat loss/muscle loss at this
caloric level, they are discussed in more detail.
In one of the earliest studies of low-carbohydrate diets, subjects were
fed 1800 calories, 115 grams of protein, and varied carbohydrate from
104 grams to 60 grams to 30 grams (18). Fat was varied in proportion to
carbohydrate to keep calories constant. The diet was fed for 9 weeks.
Total fat loss was directly related to carbohydrate content with the
highest fat loss occurring with the lowest carbohydrate content and vice
versa. Since there were so few subjects in each group, the data for
each subject is presented. The data from this study appears in table 2
on the next page.
By examining the data for each subject, some patterns emerge. First
and foremost, there is a definite trend for greater fat loss and less
LBM loss as carbohydrates are decreased in the diet. However, there is
a large degree of variability (note that subject 3 in the medium
carbohydrate group lost less muscle than subject 3 in the low
carbohydrate group). Before drawing any ultimate conclusions from this
study, it should be noted that the protein intake is still below what is
recommended in this book, which might change the results in all diet
groups. Additionally, the low carbohydrate nature of all three diets,
relative to current dietary recommendations, makes it impossible to draw
conclusions between a ketogenic diet and a more typical
high-carbohydrate diet deriving 55-60% of its total calories from carbohydrate.
Table 2: changes in body composition
Group Carb Protein Fat Weight Fat LBM
(g) (g) (g) loss (kg) loss (kg) loss (kg)
High 1 104 115 103 8.5 6.6 1.9
2 13.9 10.2 2.7
Medium 1 60 115 122 13.4 9.9 3.5
2 11.6 9.9 1.7
3 11.8 10.9 0.9
Low 1 30 115 133 Not measured
2 15.3 14.7 0.6
3 16.0 15.0 1.0
Source: Young CM et. al. Effect on body composition and other parameters
in young men of carbohydrate reduction in diet. Am J Clin Nutr (1971)
24: 290-296.
Two recent studies, both at 1200 calories found no significant
difference in the weight or fat loss between groups consuming high- or
low-carbohydrate diets (27,28) However, an examination of the data shows
a trend towards greater fat loss in the lower carbohydrate groups with
less protein loss. The data is summarized below in table 3.
Table 3: Changes in body composition for high- and low-carbohydrate diets
Study Length Carbs Protein Weight Fat LBM
(weeks) (g) (g) loss (kg) loss (kg) loss (kg)*
Golay (27) 12 75 86 10.2 8.1 2.1
135 86 8.6 7.1 1.4
Alford (28) 10 75 90 6.4 5.7 0.7
135 60 5.4 4.5 0.9
225 45 4.8 3.7 1.1
*Determined as the difference between total weight loss and fat loss
Note: in both studies, the difference in weight, fat and LBM loss was
not statistically significant, due to the high degree of variability
among subjects.
Source: Golay A et al. Weight-loss with low or high carbohydrate diet?
Int J Obes (1996) 20: 1067-1072 ; and Alford BB et. al. The effects of
variations in carbohydrate, protein and fat content of the diet upon
weight loss, blood values, and nutrient intake of adult women. J Am Diet
Assoc (1990) 90: 534-540.
Why the discrepancy between VLCD research and moderate caloric deficits?
The discrepancy between research on diets with extreme caloric deficits
versus those with more moderate deficits is perplexing. At first glance
it would seem that the greater the caloric deficit, the more fat which
should be lost. However in practice, even with sufficient dietary
protein, this is rarely the case, especially in the first few weeks of a
diet. Although the reasons for this discrepancy are unknown, some
speculation is warranted.
It appears that there are certain caloric thresholds beyond which the
physiological responses to diet and exercise change. As discussed in
chapter 22, exercise has its greatest impact in increasing fat loss and
decreasing muscle loss with moderate caloric deficits. (51) Once
calories are reduced below a certain point, exercise generally stops
having a significant effect.
It may also be that once calorie levels fall below a certain level,
there is increased muscle loss regardless of diet, especially in the
first few weeks. That is, for reasons which are not entirely
understood, the body appears to be limited in the quantity of fat it can
breakdown without some loss of protein (52). This makes it difficult
to measure significant differences in bodyfat and protein losses, simply
because they are so high in both ketogenic and non-ketogenic VLCDs.
This speculation is consistent with studies on metabolic rate showing a
much larger decrease in metabolic rate once calories reach a certain low
level (53,54). Hence this book’s recommendation to use moderate caloric
restriction with exercise. It is interesting that the study done with
the highest caloric intake (1800 calories/day) showed the most
significant differences in fat and weight loss ; but more research is
needed at this calorie level.
Along with this is the issue of inadequate protein, discussed
previously in this book. The low-calorie nature of the VLCD mandates
low protein levels. With only 400 calories per day, the maximum amount
of protein which could be consumed would be 100 grams, still lower than
the 150 grams required to prevent all nitrogen losses determined in the
last chapter. Low protein intake may be one cause of the decrease in
metabolic rate with VLCDs (55) and it seems reasonable that this could
have an impact on fat loss/LBM loss as well.
Summary
The effects of the ketogenic diet on weight and water loss are fairly
established. In general, due to the diuretic nature of ketones, total
weight and water loss will generally be higher for a ketogenic diet
compared to a non-ketogenic diet. However, once water losses, which may
represent a weight loss of 5 pounds or more, are factored out, the true
weight loss from a ketogenic diet is generally the same as for a
non-ketogenic diet of the same calorie level. This is especially true
at low calorie levels.
The research on fat and LBM losses are more contradictory and may be
related to calorie level. At maintenance calories, fat loss will not
occur. At extremely low calorie levels, below 1200 per day and lower,
there are some studies suggesting that a ketogenic diet causes more
fat/less LBM loss than a non-ketogenic diet while other studies support
the opposite. In all likelihood, the differences are due to variations
in study design, protein intake, study length, etc. Because these
studies do not mimic the types of ketogenic diets described in this
book, with a moderate caloric deficit, adequate protein, and exercise,
they should not be used as evidence for or against the ketogenic diet.
At more moderate caloric levels, one early study has shown that fat
loss increased as carbohydrate intake decreased. Two recent studies
showed no statistically significant differences, but there was a trend
towards greater fat loss and less muscle loss as carbohydrate quantity
came down. An important note is the high degree of variability in
subject response to the different diets. None of these studies provided
what this author considers to be adequate amounts of protein.
Perhaps the proper conclusion to be drawn from these studies is the
variety of approaches which can all yield good results. At the very
least, a properly designed ketogenic diet with adequate protein appears
to give no worse results than a non-ketogenic diet with a similar
caloric intake. Some research suggests that it may give better results.
Anecdotally many individuals report better maintenance of lean body
mass for a SKD/CKD compared to a more traditional diet. This is not
universal and others have noted greater LBM losses on a ketogenic diet.
The definitive study comparing a ketogenic to a non-ketogenic diet has
yet to be performed. It would compare fat loss/muscle loss for a
ketogenic diet at 10-20% below maintenance calories, with adequate
protein, and weight training to a higher carbohydrate diet with the same
calories, protein intake, and exercise.
Ultimately, fat loss depends on expending more calories than are
consumed. Some individuals have difficulty restricting calories on a
high-carbohydrate diet. If lowering carbohydrates and increasing
dietary fat increases satiety, and makes it easier to control calories,
then that may be the better dietary choice. Other potential pros and
cons of the ketogenic diet are discussed in the next chapter.
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ZE STRONY
http://www.google.pl/[email protected]&oe=UTF-8&output=gplain
............................
differences in *weight* loss are pretty easy: water.
A lowered carb diet will result in more water loss so weight loss is
almost always higher.
In terms of fat loss, in the Alford/Golay studies, I comment that there
was a lot of variability among subjects. By averaging the results, you
lose that fact. As well, the difference in fat loss was slight, 1 kg
over 10 weeks in the Golay study, 1.5 kg over 12 weeks in the Alford
study (and the high carb diet was crappy, protein was too low). The
best bodyfat measurement methods have a 3-5% error and that could
explain a few pounds either way fairly easily.
I think I mentioned that the folks I was getting feedback from might
have reported a 3 lb difference in fat loss for a keto vs. moderate carb
diet over 12 weeks, which is in keeping with these results. Any
difference tends to be fairly small overall. Even then, some folks lost
more fat on moderate carbs. I imagine that biochemical individuality as
well as error in measurement is contributing. But the differences under
most conditions are extremely slight.
The Young study is a bit tougher to explain. Looking at the study right
now, a couple of things stand out. First and foremost, there's the
tiny sample sizes: a few subjects in each group. That limits the
study's applicability but doesn't explain the trends. Although note the
rather large variance. One guy in the highest carb group lost more
weight than two of the guys in the moderate carb group. The same guy
lost slightly more fat compared to two of the guys in the moderate carb
group as well.
One thing I note right now is that there was a pretty monstrous range of
bodyweights (79-113 kg or 174-248 lbs) and bodyfat percentage (19% to
37%). Unfortunately they didn't indicate the weight/BF% of which
subjects lost how much weight/fat which would have been ideal. I'm
willing to bet that the biggest/fattest subjects lost the most
weight/fat, just as you'd expect.
the best I can do is look at the group averages. The lowest carb group
was heavier on average by about 7 kg (15 lbs) than the medium carb group
and about 4kg (~9 lbs) heavier than the highest carb group. The lowest
carb group was also a little bit fatter (31.4% bodyfat) than the medium
(30% bodyfat) or highest (28%) carb group.
So we have:
Highest carb: 98kg/28% BF
Moderate carb: 95kg/30%BF
Lowest carb: 102kg/31% BF
Another issue, something I mistakenly left out of the book. Although
they didn't report fat loss for subject 1 in group c, they did report
his weight loss: 10.77 kg. Which is less then the other two subjects
and less than what the moderate carb group lost. That same person also
didn't lose as much bodyfat in terms of mm skinfolds (I didn't put that
data in the book). Basically it looks like they put the two
heaviest/fattest subjects along with a lighter/leaner guy in the lowest
carb group. The lighter guy only lost 10 kg and a lot less bodyfat (he
lost 137 total mm of bodyfat compared to 199 and 173 mm for hte other
two subjects, folks in the moderate carb group lost 155, 155 and 164
total mm), compared to 15-16kg for the other two. Basically here's the
data for groups 2 and 3.
Subject Weight loss (kg) Skinfold loss (mm)
A1 8.5kg 118
A2 13.88 142
B1 13.38 155
B2 11.56 164
B3 11.8 155
C1 10.77 137
C2 15.25 199
C3 15.99 173
It really does look like they put the two fattest (and presumably
heaviest) subjects in the lowest carb group. They lost the most
weight/fat, which you'd expect since 1800 calories is a larger deficit
for them. The third subject in group C had to have been lighter/leaner
since he lost less weight and total fat (by skinfolds). But he kept
the average weight/BF% of the group down.
But looking at those numbers, the lowest carb group doesn't come out as
superior across the board anymore. Subject C1 lost less weight and fat
than subject A2 for example. And the entire B group lost more
weight/fat than subject C1. And I do really suspect that the variance
in weight/fat loss had more to do with starting weight/fat than anything
else. It's too bad they didn't list starting weight/BF% for each
subject along with individual results, that would have answered it once
and for all.
Beyond those possibilities: magic.
.................
Back in the 70's, they used to lock folks in
metabolic wards for weeks on end and really control caloric intake.
Now, they usually just give prepared food packets. But such studies
have been done, where calories are controlled much more rigorously than
'we told folks to do this and let them report what they think they did,
and then we believed them'.
Those studies, where caloric intake is actually controlled (usually by
giving subjects pre-prepared food packets) show no such discrepancies in
weight loss: it all scales with calories regardless of the composition
of the diet. High carb, low-carb, whatever you want to pick; everybody
loses weight (yes, there is variance for reasons I've mentioned before).
but none of these claimed metabolic anomalies, folks who magically
failed to lose weight on a low calorie diet has EVER showed up in the
HISTORY of diet studies. Yet there seems to be literally dozens or more
of them on every diet support group. To which I say this: go to a
metabolic ward, have them lock you in a room and control your caloric
intake down the joule, you'll lose weight no matter what the diet is
composed of. Then please sit the **** down and shut the **** up.
Which makes the results of these vaguely controlled studies debatable at
best and dismissible at worst.
So, to reiterate yet again for the slow readers on asd and asdlc, we
have basically two data sets.
1. A data set of controlled calorie studies (at varying calorie levels
and varying amcronutrient composition), that is where calories are being
controlled (attemps to control activity are generally made) and the
subjects are being given fed a set amount. I've already references
studies by Golay and Adler on this topic.
2. A data set of studies where subjects are given instructions and then
the researchers rely on self-reporting of food intake (said self-reports
having been shown to be wildly inaccurate under most conditions). The
two studies in contention fall into this category.
dAta set 1 shows no such major differences in weight loss (and rarely in
tissue loss, that is protein and fat, as long as a few basic
requirements, such as adequate protein and not setting too high of a
caloric deficit) between groups: it's all about caloric intake.
data set 2 shows major differences.
Which set to believe?
Well, the fat ****s can whine all day long but I'll take controlled
studies (i.e. where caloric intake is being rigorously controlled) over
non-controlled (i.e. where researchers are relying on subject's
notoriously bad reporting) any day.
And those controlled studies consistently show the same end result: it's
all (ok, 99%, you need adequate protein and extremely low caloric
deficits tend to cause more muscle loss than less extreme deficits)
about caloric intake. Diet composition basically only matters in terms
of adherence (which is an important but tangential issue).
Oh yeah, most of these studies are done in the obese so your point about
that is sort of moot. It might be that things change a bit (mostly in
terms of the composition of what's lost) when folks get very lean but
none of the studies in question are testing diets in lean folks (why
bother).
Incidentally, in one of the few diet studies done in lean athletes
(wrestlers all at the sub 10% bodyfat range), even though carbs were
nearly 60% of total calories (the study was looking at variations in
protein and such), since the diet was hypocaloric, EVERY subject lost fat.
Fakty, nie mity - stan wiedzy na rok 2003
'Alternatywna Droga'
blomdina
czym wiecej czytam tym mniej wiem;-(
Biniu
kanarek
