Re: The definitive study on dietary fat and weight



"runnswim@xxxxxxx (Larry Weisenthal)" <runnswim@xxxxxxx> wrote in part:

>>>I would be interested in seeing this study. All evidence I've seen indicates
>that low-carb diets (ad libitum, no low-carb diets that I'm aware of
>involve
>"force feeding") are better. A google search finds nothing either for
>that
>name and "carbohydrate". <<
>
>Joe,
>
>Virtually all of the head to head "low fat" versus "other" diet studies
>ever published have involved an isocaloric feeding design. The
>researchers prescribe a set amount of calories to be fed to the study
>subjects. Each group ("low fat" versus "other") gets the same amount
>of calories per day. What ends up happening is that the "low fat"
>group gets fed more calories than they would take in if you just let
>them select foods from a buffet table and eat what they wanted. So you
>are, in effect, force feeding them. Also, you may be giving the
>"other" group fewer calories than they might otherwise choose to take
>in, so you are, in effect, putting them on a diet. A similarly flawed
>study design is to feed the subjects the number of calories per day
>required to maintain their baseline weight ("weight maintenance diet").
> When subjects are placed on reduced fat diets, they tend to lose
>weight. Again, when you adjust their caloric intake to maintain weight,
>you are, again, force feeding them. I cited several recent editorials
>and discussions which noted this particular fatal flaw in these
>studies.
>
>The only studies which are real world studies are those examining what
>subjects do when they are allowed to choose their foods (from among a
>selection) and choose their portions. In all such studies of which I
>am aware (except for studies where high sugar/low quality carbs were
>administered in the "low fat" arm of the study), the high carb group
>does, at minimum, equally well as the "other" group. And this is not
>even including the fact that the only healthy lifestyle is one
>including daily exercise and these studies are most commonly being done
>on couch potatoes.
>
>Here's the paper I quoted. Note that when the subjects were fed a low
>fat/high carb diet under weight maintenance conditions, they got worse.
> But when they were allowed to eat what they want, on the same low
>fat/high carb diet, they got better.
>
>1: JAMA. 1995 Nov 8;274(18):1450-5.
>
>Body weight and low-density lipoprotein
>cholesterol changes after consumption of a low-fat
>ad libitum diet.
>
>Schaefer EJ, Lichtenstein AH, Lamon-Fava S,
>McNamara JR, Schaefer MM, Rasmussen H, Ordovas JM.
>
>Lipid Metabolism Laboratory, Jean Mayer USDA Human
>Nutrition Research Center on Aging at Tufts
>University, Boston, MA 02111, USA.
>
>OBJECTIVE--To assess the effects of a diet
>restricted in fat, saturated fat, and cholesterol,
>under weight-maintenance and ad libitum conditions
>on body weight and plasma lipid levels in
>hypercholesterolemic subjects. DESIGN--Dietary
>intervention study. SETTING AND
>PARTICIPANTS--Twenty-seven free-living, healthy
>middle-aged and elderly men (n = 13, age range, 41
>to 81 years) and women (n = 14, age range, 52 to
>79 years) with moderate hypercholesterolemia
>(low-density lipoprotein cholesterol [LDL-C] > or
>= 3.36 mmol/L [130 mg/dL]) participated in the
>study. INTERVENTION--Subjects underwent three
>dietary phases. First, subjects were provided with
>a diet similar to the average US diet (baseline
>diet; 35.4% total fat, 13.8% to 14.1% saturated
>fat, and 30 to 35 mg/1000 kJ [128 to 147 mg/1000
>kcal] cholesterol). During the second dietary
>phase, subjects consumed a low-fat diet (15.1%
>total fat, 5.0% saturated fat, 17 mg/1000 kJ [73
>mg/1000 kcal] cholesterol). During the baseline
>and low-fat diet phases, which lasted 5 to 6 weeks
>each, the energy intake was adjusted to keep body
>weight constant. During the third diet phase
>(low-fat ad libitum diet) subjects were given the
>same low-fat diet for 10 to 12 weeks, but could
>adjust their intake between 66% and 133% of the
>energy required to maintain body weight. MAIN
>OUTCOME MEASURES--Body weight and plasma lipid
>levels. RESULTS--Consumption of the low-fat diet
>under weight-maintenance conditions had
>significant lowering effects on plasma total
>cholesterol (TC), LDL-C, and high-density
>lipoprotein cholesterol (HDL-C) levels (mean
>change, -12.5%, -17.1%, and -22.8%, respectively).
>This diet significantly increased plasma
>triglyceride levels (+47.3%) and the TC/HDL-C
>ratio (+14.6%). In contrast, consumption of the
>low-fat ad libitum diet was accompanied by
>significant weight loss (3.63 kg), by a mean
>decrease in LDL-C (124.3%), and by mean
>triglyceride levels and TC/HDL-C ratio that were
>not significantly different from values obtained
>at baseline. CONCLUSIONS--Our results indicate
>that a low-fat ad libitum diet promotes weight
>loss and LDL-C lowering without adverse effects on
>triglycerides or the TC/HDL-C ratio in middle-aged
>and elderly men and women with moderate
>hypercholesterolemia.
>
>PMID: 7474191 [PubMed - indexed for MEDLINE]
>
>>>>
>
>- Larry W

Got it. Very interesting.
--
Jim Chinnis Warrenton, Virginia, USA jchinnis@xxxxxxxxxxxx
.