Dear forumites!
This is my first post in this forum, and I really want to share an issue which I experienced digging through all the studies.
In the first place, there are two main hypotheses which go around.
Fat is Bad and
Carbs are Bad There are
numerous credible studies which give us a solid evidence that the second one is a valid theory. It has been proven, beginning with the
Jenkins study that fat and proteins do nearly nothing to blood sugar levels, while carbs are the insulin trigger No.1. On the other side, Low Fat proposers all stick to Fat is Bad - hypothesis, claiming that it's fat which causes obesity, diabetes, cardiovascular disease and artherosclerosis. I was confronted many times with this hypothesis while debating Vegans, and of course I asked them for assorted studies which prove that fat is indeed causing all this. Anf they gave me such studies. In addition I did my research on my own, through all the diet forums, vegan sites and Co. Now I like to prsent what I found.
OK. Dr. Ornish, Dr. McDougall and other famous High Carbers actvely promote 60-70% of our diet to be of carbs like potatoes, rice, wheat, rye and other whole grains. But what are their ideas based on? Here are the most credible studies on High-Fat-Low-Carb Vs. Low-Fat-High-Carb I was able to find!
Study 1. The most credible one.
Nathan A. Johnson: Effect of short-term starvation versus high-fat diet on intramyocellular triglyceride accumulation and insulin resistance in physically fit men. School of Exercise and Sport Science, The University of Sydney, Lidcombe 1825, Australia.This one was sited to support Fat is Bad hypothesis. However, if you take the time to read through it, for anti-fatters it ends in nowhere.
Diet:
Quote:
an isocaloric meal comprising 1% energy as CHO, 98% as fat and 1% as protein in the LC (=low carb) treatment.
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Insulin level findings:
Quote:
The basal plasma insulin concentration was significantly lower in S versus C (P < 0.01) and in LC versus C (P < 0.05). ... Plasma insulin (pmol l−1): Carb diet 22,9 (9,8); Low Carb 14.1 (6.4); Starvation 10.7 (4.6), see Table 3
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But about FAT?
Quote:
In contrast to CHO, fat intake has previously been shown to exert no effect on adipose lipolysis, whole-body substrate selection or plasma FFA and insulin concentrations (Klein & Wolfe, 1992; Schwarz et al. 1995). Thus, we suggest that dietary-induced IMTG accumulation and insulin resistance in healthy humans may be largely influenced by circulating FFAs, whose availability (in turn) is regulated by dietary CHO intake. ... These findings may indicate that short-term dietary-induced IMTG accumulation and the concurrent development of insulin resistance in physically fit men are mediated largely by dietary CHO restriction rather than fat intake. .. Taken together, these findings provide support for our hypothesis that short-term restriction of CHO intake independently influences IMTG accumulation and insulin resistance.
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A very clear statement that fat by itself had no effect on the increase of insulin resistance, which was mainly a natural responce of the body to a harsh carb restiction, a body which is trained to be constantly fed with carbs. And from the study data we see this one is a true Low Carb diet. CONCLUSION: Everyone who sites this study as a proof that "fat increases insulin levels" is hoping that you're ignorant enough not to read the text.
Study 2.
Rebecca L Adochio: Early responses of insulin signaling to high-carbohydrate and high-fat overfeeding. © 2009 Adochio et al; licensee BioMed Central Ltd.
And our search for truth ends here:
Quote:
To investigate the molecular correlates of metabolic adaptation to either high-carbohydrate (HC) or high-fat (HF) overfeeding, we conducted overfeeding studies in 21 healthy lean (BMI < 25) individuals (10 women, 11 men), age 20-45, with normal glucose metabolism and no family history of diabetes. Subjects were studied first following a 5-day eucaloric (EC) diet (30% fat, 50% CHO, 20% protein) and then in a counter balanced manner after 5 days of 40% overfeeding of both a HC (20% fat, 60% CHO) diet and a HF (50% fat, 30% CHO) diet.
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We see here staggering 30% carbs which were fed to probands, along with 50% of fat! The findings of the study were not suprising. I got this one labeled as "see?! Fat increase did harm, therefore fat is bad!!"
Just for the sake of comparison, here is the
nutritional data of a infamous burger: 200g of this product contain 11,55% (23,1g) fat, 21% (42g) carbs and 12,8% (25,6g) protein. And we know this product as "especially heathy and non-fattening"
Not to say about 30% carbs...
Study 3.
G. Boden: Free fatty acids, insulin resistance, and type 2 diabetes mellitus. Division of Endocrinology/Diabetes/Metabolism and the General Clinical Research Center, Temple University Hospital, Philadelphia, PA 19140, USA.
Quote:
The resulting insulin resistance/secretion deficit will then have to be compensated for with glucose-induced insulin secretion, which, because of their partial "glucose blindness," will result in hyperglycemia and eventually in type 2 diabetes.
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Other works of this author also suggest that FFA increase is indeed associated with insulin resistance, which is completely d'accord with N. A. Johnson study I listed first. Johnson study (and others, he cited) however clearly show that Fat intake does not correlate with FFA increase at all, as well as insulin concentrations! CONCLUSION:
Anyone who sells you these studes as proof of "fat vile-ness" just draws a fantasy line between fat intake and increase of FFA's which has never been proven in studies! At least no one is known to me. Increase of FFA's is a complex process where al parts of diet play their role, as Johnson suggests, and carb restriction can lead to it as well.
Study 4.
B. A. Swinburn: Deterioration in Carbohydrate Metabolism and Lipoprotein Changes Induced by Modern, High Fat Diet in Pima Indians and Caucasians. Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Phoenix, Arizona 85016
Quote:
In this study, 12 Pimas and 12 Caucasians, all nondiabetic, were admitted to a metabolic ward and, in random order, fed 2 14-day weight-maintaining diets: a traditional Pima diet (percentage of calories: carbohydrate, 70%; fat, 15%; protein, 15%) and a high fat modern diet (carbohydrate, 30%; fat, 50%; protein, 20%). ... Compared with the traditional diet, the modern diet was associated with a decrease in oral glucose tolerance (P < 0.01) and higher plasma cholesterol concentrations (P < 0.02).
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I wonder why...
Maybe its all about the usual 30% carbs??? Nothing more to say here.
Study 5.
Lourdes M Varela, Almudena Ortega, Beatriz Bermudez, Sergio Lopez: A high-fat meal promotes lipid-load and apolipoprotein B-48 receptor transcriptional activity in circulating monocytes. AJCN. First published ahead of print March 2, 2011
Oh Lord, here we go again...
Quote:
The study was designed as a single-blind, randomized, withinsubject
crossover in which the volunteers attended the Research
(Internal Medicine) Unit at the Hospitales Virgen del Rocio.
Fasting blood samples (t = 0) were taken at 0800 after the subjects
fasted overnight (12 h). Immediately afterward, the subjects ingested
a high-fat meal within 15 min, which consisted of dietary
fat (butter; 50 g/m2 body surface area), a portion of plain pasta
(30 g/m2 body surface area), one slice of brown bread, and one
skimmed yogurt (11). The average total energy provided by the
high-fat meal was ’800 kcal (’10 kcal/kg) with a macronutrient
profile of 72% fat, 22% carbohydrate, and 6% protein. The subjects
also consumed the same test meal containing no fat as
a control meal. There was an interval of ’2 wk between meals.
Blood samples were collected 1, 2, 3, 4, 6, and 8 h after ingestion
of the meals.
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Anything suspicious? 22% carbs in form of pasta and bread are not relevant at all, it's just fat, of course... [/sarcasm] *FACEPALM*
Two random less known early studies.
...Which are still sold as "bulletproof evidence" that fat is bad...
Elliot B, Roeser HP, Warrell A: Effect of a high energy, low carbohydrate diet on serum levels of lipids and lipoproteins. 1981 Mar 7
Two(!) probands were tested a high-fat diet of unknown composition. Long-term? No. Best suitable for sensational propaganda? Yes.
Frank Rickman, MD: Changes in Serum Cholesterol During the Stillman Diet. JAMA. 1974
The study tried to test the efficacy of Stillman diet, which is actually protein based and nowhere near "High Fat."
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These studies actually show us one thing - Standard Americal Diet with their up to 50% fat and 30% carbs is harmful! Fat by itself does not increase insulin resistance, does not cause diabetes and does not cause obesity related to previous dieases. Fat by itself is also not connected to FFA/cholesterol increase, which is associated with arthersclerosis and cardiovascular diseases. Studies like
THIS ONE (there are dozens like this one) is not based on carb restriction, and can't say anything about fat itself. Two ketogenic studies:
Yancy WS Jr, Olsen MK: A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial. Center for Health Services Research in Primary Care, Department of Veterans Affairs Medical Center, and Duke University Medical Center, Durham, North Carolina 27705, USA.
Dashti HM, Al-Zaid NS, Mathew TC: Long term effects of ketogenic diet in obese subjects with high cholesterol level. Department of Surgery, Kuwait University, Safat, Kuwait.
... are completely pro low-carb, and shows significant improvements in health! Especially the last one, done on obese people, showed clearly the benefits for those who suffer obesity.
Decreasing cholesterol by eating lots of good fat and minimum carbs seems to be the worst horror for anti-fat proponents.
But High Carbers are constantly siting most of these studies as a proof that it is the fat which caused all the disease, making it evident that they just go by single lines (="quote mining") with the intention to impress people. Most of them seem not to read the whole abstract in the first place. Dr. Ornish is the best example of promoting High Carb loudly, his latest crusade against Atkins led him to publish
THIS, which is the best example of mislabeling things according to his taste.
To call 37-60% carb based diet "Atkins diet" is the same as labeling glucose-fructose sirup "healthy and non-fattening"...
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In the end we end up with blanket statements like "everyone knows that fats increase cholesterol levels which cause cardiovascular diseases and arthersclerosis"", but with no real scientific proof, besides the scientifically proven fact that 30% carb 50% fat diets are harmful.
The state of scientific knowledge today, derived from all the studies - Low Carb diets, if done correctly, will improve your health in most cases. Fat by itself(!) does not cause any of those diseases (obesity, diabetes, arthersclerosis, cardiovascular issues) which are traditionally associated with fat!.
Please comment and give links to studies, if you know good ones, which
seemingly give conclusive evidence that fat is bad for health by itself.
Best Wishes
ketogenium