Low Fat vs Low Fat: Is there a difference

May 3, 2005

Not all low fat diets are created equal....

Abstract and 2 lay articles on the study below.

Jeff

ANNALS OF INTERNAL MEDICINE

ARTICLE

The Effect of a Plant-Based Diet on Plasma Lipids in Hypercholesterolemic Adults

A Randomized Trial

D. Gardner, PhD; Ann Coulston, MS, RD; Lorraine Chatterjee, MS;

Alison Rigby, PhD, MPH, RD; Gene Spiller, PhD; and W. Farquhar, MD

3 May 2005 | Volume 142 Issue 9 | Pages 725-733

Background: A variety of food combinations can be used to meet national U.S.

guidelines for obtaining 30% of energy or less from total fat and 10% of energy

or less from saturated fat.

Objective: To contrast plasma lipid responses to 2 low-fat diet patterns.

Design: Randomized clinical trial.

Setting: 4-week outpatient feeding study with weight held constant.

Participants: 120 adults 30 to 65 years of age with prestudy low-density

lipoprotein (LDL) cholesterol concentrations of 3.3 to 4.8 mmol/L (130 to 190

mg/dL), body mass index less than 31 kg/m2, estimated dietary saturated fat at

least 10% of calories, and otherwise general good health.

Measurements: Plasma lipid levels.

Intervention: Two diets, the Low-Fat diet and the Low-Fat Plus diet, designed to

be identical in total fat, saturated fat, protein, carbohydrate, and cholesterol

content, consistent with former American Heart Association Step I guidelines.

The Low-Fat diet was relatively typical of a low-fat U.S. diet. The Low-Fat Plus

diet incorporated considerably more vegetables, legumes, and whole grains,

consistent with the 2000 American Heart Association revised guidelines.

Results: Four-week changes in the Low-Fat and Low-Fat Plus groups were -0.24

mmol/L (-9.2 mg/dL) versus -0.46 mmol/L (-17.6 mg/dL) for total cholesterol (P =

0.01) and -0.18 mmol/L (-7.0 mg/dL) versus -0.36 mmol/L (-13.8 mg/dL) for LDL

cholesterol (P = 0.02); between-group differences were -0.22 mmol/L (-9 mg/dL)

(95% CI, -0.05 to -0.39 mmol/L [-2 to -15 mg/dL]) and -0.18 mmol/L (-7 mg/dL)

(CI, -0.04 to -0.32 mmol/L [-2 to -12 mg/dL]) for total and LDL cholesterol,

respectively. The 2 diet groups did not differ significantly in high-density

lipoprotein cholesterol and triglyceride levels.

Limitations: 4-week duration.

Conclusions: Previous national dietary guidelines primarily emphasized avoiding

saturated fat and cholesterol; as a result, the guidelines probably

underestimated the potential LDL cholesterol-lowering effect of diet. In this

study, emphasis on including nutrient-dense plant-based foods, consistent with

recently revised national guidelines, increased the total and LDL

cholesterol-lowering effect of a low-fat diet.

http://tinyurl.com/cu82s

and

http://tinyurl.com/aydox

February 8, 2006

Jeff,

In the ls study you posted in terms of diet effects on cholesterol:

>>>>>>>>>>>>>

Results: Four-week changes in the Low-Fat and Low-Fat Plus groups were

-0.24 mmol/L (-9.2 mg/dL) versus -0.46 mmol/L (-17.6 mg/dL) for total

cholesterol (P = 0.01)

and -0.18 mmol/L (-7.0 mg/dL)

versus -0.36 mmol/L (-13.8 mg/dL) for LDL cholesterol (P = 0.02);

between-group differences were -0.22 mmol/L (-9 mg/dL) (95% CI, -0.05

to -0.39 mmol/L [-2 to -15 mg/dL]) and -0.18 mmol/L (-7 mg/dL) (CI,

-0.04 to -0.32 mmol/L [-2 to -12 mg/dL]) for total and LDL

cholesterol, respectively. The 2 diet groups did not differ

significantly in high-density lipoprotein cholesterol and

triglyceride levels.

>>>>>>>>>>>>>>>

First, there was no benefit of the plant-based diet in terms of HDL

cholesterol or triglyceride.

More importantly, the differences in changes in LDL cholesterol

between the study and control groups certainly were not marked:

LDL cholesterol:

-7 mg in the control group vs. -14 mg in the super diet group.

So only a 7 mg difference in LDL cholesterol between the two groups.

So this difference in LDL amounts to what - 5% of the baseline LDL level?

There was an earlier discussion on this board about " statistically

significant " vs. " clinically important " .

This particular study might be a good one to illustrate this issue.

February 8, 2006

>>>First, there was no benefit of the plant-based diet in terms of HDL

cholesterol or triglyceride.

Thats not always a bad thing. HDL is way overated. Using MUFA oil in monkeys

to raise their HDL resulted in more atherosclerosis than the monkeys who had

butter added. So, HDL is not always a great indicator.

There was no " super diet " . Its an example that there are differences that need

to be recognized and accounted for. . I dont think it is the best example but

it was readily in my files. Forgive me. But, the point still stands which is

more important. .

If they are going to use the term " low fat " they have to define it and the

composition of the total diet. We should get away from terms like low fat, or

high carb, or high protein, and look at the complete overall picture of all the

nutritional components and rate the diet in how well it meets those

requirements.

Yes, in the study above, the fat was similar but by making some minor changes

(yes minor) in the compostion of the two equally low fat diets, there were

statistically significant differnce. In LDL, which " may " be the most important

single marker of the lipid profile.

A year or so ago, I posted a famous headline where the MED diet was supposed to

have out performed the low fat diet. Then I posted the two diets with their

analysis and asked if anyone could guess which was which. The diet called the

low fat diet actually was the one that had 10% more total fat, 50% more

saturated fat , 50% more cholesterol, less fiber and less EFAs and more calories

Rodney has shown here how quotes from some of Dr Castelli studies and his own

statements, flood the internet, yet, as he admitted to Rodney, they are

misquotes taken out of context and misrepresent the actual conclusions...

The news right now and the media is flooded with the headlines that low fat

diets are not protective for CVD and certain cancers. It failed to meet the

minimum recommendations of the American Institue for Cancer Research or the

American Heart Association, which are barely intensive enough to produce

results.

The diet was not low fat, nor was it a healthy version of any diet. Slightly

" better " is not what is needed to show results. Nor was there enough variance

in the major issues, like saturated fat, fiber, veggie intake, whole grains, etc

for an effect to be seen.

Its like taking two groups to compare 2 mgs of lipitor to 6 mgs of lipitor for

one year on lipid profiles and when it is over , reporting that lipitor is

ineffective in lowering cholesterol or improving lipid profiles, even when 300%

the amount is used. Therefore lipitor is worthless as a drug.

Jeff

>> It does amaze me, that with all of the studies out there, we still

don't really know the answers to some very basic questions.

PS if you beleive there is so much unknown to really know anything, even basic

questions, what criteria did you use to evaluate the data and recommendations in

your book? And, if we really beleive we dont know that much, isnt it

irresponsible to write a book for the public with recommendations?

February 8, 2006

> PS if you beleive there is so much unknown to really know anything,

even basic questions, what criteria did you use to evaluate the data

and recommendations in your book? And, if we really beleive we dont

know that much, isnt it irresponsible to write a book for the public

with recommendations?

-----------------------------------------------------

Jeff,

Thanks for your response. Your points about needing to define diet

composition in these studies are well taken. However, with regard to

the example you cited, most care providers will treat high serum

cholesterol now with statins and not primarily with changes in diet,

rightly or wrongly, since the reports are mostly like the one you

listed - studies show a disappointingly small effect of diet change

alone on serum LDL cholesterol. Of course in some patients

cholesterol can go way down with changes in diet, especially in the

context of weight loss if they were massively obese to begin with. I'm

sure there are people in this group who have enjoyed marked falls in

their serum cholesterol based on diet alone. It's not clear how much

of this is due to reducing the total amount of food eaten vs. changing

the type of food eaten. It's just that when you do a randomized study

of reducing certain TYPES OF FOOD in a group of unselected people, you

don't usually see that much of a change in cholesterol on average.

With CR it's also a bit of a tough call, since malnutrition causes a

low cholesterol, and sometimes the line between severe CR and a bit of

malnutrition may be a bit fuzzy. Whether a low cholesterol in the

context of malnutrition is good or bad is really unknown.

Observational studies suggest that it's bad, but depressed, suicidal

people often pine away and don't eat, become malnourished, and commit

suicide - so what? That sheds no light on a low serum cholesterol

level in someone who is happy and doing CRON. So we just don't know.

In specific response to your postscript, my uncertainty is in the area

of the benefits of what types of food we eat, not the quantity. It is

clear that people in the U.S. are becoming obese because they are

eating too many calories for their level of activity. The problem is,

with some diet books, people are led to think that if they change the

types of food they eat, they will lose weight or obtain other marked

health benefits. I do agree with you that at least part of the benefit

of many diets is in simply restricting caloric intake. You can have

an " avoid yellow food " diet, or " eat only foods that begin with the

letter 'b' " diet, and probably these will be effective in short-term

weight loss. Because we're in a situation of abundance and ready

availability of food, any maneuver that restricts food is bound to be

beneficial in obese patients, as long as it's combined with a freedom

to let people eat what their bodies " need " .

I personally sometimes feel my body crying out for a steak, or some

eggs, or some nice fatty dessert. I believe a lot of the bad press

that saturated fats and even sugar, have gotten derive more from

quantity of food eaten, than these being inherently bad foods. So I

think people doing CR can easily eat a donut once in awhile and be

fine with it. I think that's the real meaning of the " French

paradox " . Until recently, the French ate less food - 3 meals a day

with little snacking, and they walked everywhere.

So I was just never a big fan of the change the type of food approach,

with the exception of one factor- it is probable that eating certain

types of foods will induce you to eat more. Sugary and salty foods

fall in this category. On the other hand, proteins and fats and high

fiber foods do tend to be satiating, etc. etc.

I didn't agree, for example, with the movie " Supersize Me " . The

person in the movie gained all of his weight because he ate way too

much food. He was probably eating over 5000 calories per day, with

very little activity. I find nothing inherently unhealthy in a Big

Mac or even the fries (although I don't usually order these). (OK,

with AGEs, you've sort of got me there, but it's the manner of cooking

and not the food!) I do believe that soft drinks are inherently

unhealthy, given the very unnatural amount of pure sugar that they

contain. I also believe there is intriguing data about increasing use

of high-fructose corn syrup - since fructose-feeding is a great model

of inducing obesity in animals.

That being said, there probably are certain health benefits to

different classes of food, including meats and saturated fats, and of

course it's unhealthy to eat any one food type to excess.

Getting back to your postscript, in the QOD diet I was focusing

primarily on a relatively easy way to reduce the overall quantity of

food eaten by doing a sort of IF (intermittent fasting) approach while

maintaining mineral intake and some intake of hbv protein. With

regard to type of food, I did, actually, take a sort of agnostic

approach, while hewing fairly close to government and other regulatory

guidelines, counseling a good carb approach, and general avoidance of

eating too many saturated fats. In fact I do criticize the

ultra-low-carb approach - based on what I think is relatively new info

about its potential adverse effects on urinary calcium and uric acid.

So there's little debate that if you reduce calories you will lose

weight :-) (and most likely live longer, especially if you started out

being obese). Also, there appear to be health and longevity enhancing

benefits of CR, although these data are not in people. It's the

qualitative aspect of food (choices among carbs, fats, and proteins)

where I'm not prepared to be so dogmatic.

I do believe that this is an important discussion for people doing CR.

When you are restricting total calories, cutting out certain classes

of food because you feel they are inherently unhealthy may be quite

risky, since each type of food contains certain nutrients and

micronutrients that may not be in other classes of foods. A nice,

marbled steak for someone doing moderately strict CR may be " just the

ticket " once in a while to replenish body stores of nutrients they

need. I don't think that people should be afraid of any one type of

food, and I do believe that the " body knows best " , and that listening

for specific hungers is the best approach when doing CR, with as few

conceptual restrictions as possible.

February 8, 2006

Since studies are what the scientific establishment accepts, they're a helluva lot better than one person's personal opinion (and better than a bias to throw them out the window) . You'll have to post studies in the future to back up your assertions such as the ones below (or they don't get posted) . Personal opinions don't cut it around here.

on 2/8/2006 2:36 AM, jt_qod at jt@... wrote: