FOOD, FACTS and FADS

Exploring the sense and nonsense of food and health


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Low Carb/Low Fat: Which Diet is Best?

Which diet is best for weight loss? This debate has been a hot topic of nutritionists and dieters that began when Nathan Pritikin (a low fat guru) and Dr. Robert Atkins (a low carb supporter) faced off at a diet conference decades ago.

As People Magazine described it:

“Breakfasting within sight of each other during a recent diet conference, two of America’s leading gurus of weight loss were in no mood to break bread—or chew the fat. At one table Dr. Robert Atkins gobbled down bacon, ham and eggs, but carefully pushed the toast to the side of his plate. Nearby, he says, Nathan Pritikin was munching on nothing but plain toast. “I looked over at him eating his dry bread,” Atkins recalls scornfully. “And he looked so pathetic.” What does Pritikin think of Atkins’ bill of fare? “His diet is a monstrosity,” Pritikin says. “It’s really a malignancy of nutrition.” From People Magazine, December 3, 1979.

Since then, this controversy  has continued relentlessly – until now.  Maybe, just maybe, we can accept one “truth” – it really doesn’t matter for weight loss.

However, the following article does not address that there are some major differences in health affects between the two diets- namely, their effects on heart disease risks (LDL cholesterol, triglycerides, HDL cholesterol). Those differences in time may help to clarify the debate about the lipid hypothesis of heart disease. Check out my previous post HERE.

Read the article HERE.


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A Case for High Carbohydrates?

What can we learn about diets from the Japanese? They have low rates of major chronic disease and have a high life expectancy. They eat a diet high in carbs and still have a low incidence of obesity. How do they do it?  Again, it may be the kinds of carbs (there are some healthy carbs) they eat, get more exercise and follow a low fat diet.

The Traditional Japanese Diet:

  • The diet is one of the lowest in fat – traditionally the Japanese get  26% of their calories as fat – about 8% lower than the U.S.
  • Fish is favorite protein source.
  • Soy foods are abundant.
  • They focus on presentation enhancing the  enjoyment of food.
  • They eat little processed food. They eat real food.
  • They eat about 65% of their calories from carbohydrate – mainly rice.

Bottom Line:

Japan: High carbs, more exercise, low fat

U.S.: High carbs, less exercise, high fat. Think of the popularity of ice cream or a candy bar. Sugar plus fat wins out every time. Much of our highly processed foods are loaded with both.

CLICK HERE.

For more on Asian diets, CLICK HERE.


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The Demise of the Low Fat Diet?

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Oh my – all those years of counting fat grams and eating Snackwell cookies?  What a waste of time.  Good riddance to the low-fat diet.  Some say it made us all gain weight?  The low carbohydrate diet has a long history whereas the low fat diet appeared in the 1980’s due to the concerns about fat and heart disease.  You may enjoy a previous post on diet history HERE.

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The Dietary Guidelines Dilemma

English: The blue circle is the global symbol ...

English: The blue circle is the global symbol for diabetes, introduced by the International Diabetes Federation with the aim of giving diabetes a common identity, supporting existing efforts to raise awareness of diabetes and placing the diabetes epidemic firmly in the public spotlight. (Photo credit: Wikipedia)

After years and years of basically the same Dietary Guidelines recommendations ( low fat and more carbohydrates),  the U.S. is in the midst of a serious dietary problem – obesity and an increase in the incidence of diabetes type 2.  Maybe it’s time for a change, but it looks like that will not happen this time around – the 2015 version.

CLICK HERE.


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Diets, Weight Loss and Health

English: A display of high fat foods such as c...

English: A display of high fat foods such as cheeses, chocolates, lunch meat, french fries, pastries, doughnuts, etc. Reuse Restrictions: None – This image is in the public domain and can be freely reused. Please credit the source and/or author listed above. (Photo credit: Wikipedia)

Is there a heart healthy diet? Do people lose more weight with a low fat or low carbohydrate diet? In the past few decades, thanks to Nathan Pritikin and Ancel Keys, fat phobia and heart health dominated nutrition advice. Even now, most people still think that high fat is associated with heart attacks. More recently our thinking about fats has changed – we now accept that not all fats are created equal in terms of health. The term “healthy fats” have entered the nutrition vocabulary. But what do we really know about the role of diet in heart disease, health and weight loss?

The old paradigm emphasized restriction of saturated fat and cholesterol but presently, that worn-out concept is being questioned.  The requirement was that people eat less than 20% of calories as fat. The problem was exacerbated with low-fat products becoming loaded with sugar to compensate for this restriction and people were encouraged to eat carbohydrate with abandon whether it was healthy carbohydrate or not. For example, the old Food Guide Pyramid encouraged people to eat 6-11 servings of bread, cereal, rice and pasta a day. A controversial diet book called Calories Don’t Count even became a best seller. Although not the only factor, the obesity epidemic began during the decades of attempting to follow low-fat recommendations.

How does the latest trend of the low carbohydrate diet compare? Dr. Robert Atkins took the diet world by storm and people abandoned their egg white omelets for bacon and attempted to follow the Atkins Diet Revolution.A low-carb diet limits carbohydrates — such as those found in grains, starchy vegetables and fruit — and emphasizes foods higher in protein and fat.  There are  varying restrictions on the types and amounts of carbohydrates you can eat, but 50-100 grams is commonly accepted as reasonable carbohydrate restriction; however, there is no consistent definition of  low carbohydrate.

The metabolic syndrome now gives us more of an idea of the factors that may contribute to heart disease. There are six parameters of this syndrome that have been identified that relate to heart disease: abdominal obesity, atherogenic dyslipidemia (low HDL, elevated LDL, high triglycerides) raised blood pressure, insulin resistance ± glucose intolerance, and a proinflammatory state. Along with age and lack of exercise, this syndrome risk increases even more.

In my opinion, the following statements reflect our current knowledge when we compare diets related to weight loss and/or our  health.

  • The jury is still out as to whether low fat or low carbohydrate diets play a role in heart disease directly. No one knows if sugar affects heart disease.
  • The American Heart Association recommends a diet that emphasizes fruits, vegetables, whole grains, low-fat dairy products, poultry, fish and nuts. It limits red meat and sugary foods and beverages.  This diet is very restrictive in that people cannot maintain it for very long due to restrictions on nutrient-dense foods like red meat and foods high in saturated fat and cholesterol.
  • Low-fat diets high in polyunsaturated fats tend to lower LDL-cholesterol. Often HDL-cholesterol is decreased in the process.
  • Initial weight loss is usually more rapid in the low carbohydrate approach, but over time, both low-fat and low carbohydrate result in modest weight loss (an average of about 10 pounds in 1 year according to most studies).
  • Existing evidence suggests that carbohydrate restriction positively affects most of the components of the metabolic syndrome. Waistline is reduced, blood pressure is improved, triglycerides and HDL-cholesterol improve, there will be less insulin resistance, and glucose metabolism improves.
  • Most people regain their weight loss within one to five years.
  • A low carbohydrate diet is often a better choice for people with gastrointestinal problems since some carbohydrate foods contain components that aggravate some conditions like gluten sensitivity or irritable bowel syndrome.
  • Whether it is a low fat or a low carbohydrate diet, both are restrictive. Overly restrictive diets don’t work since people find it difficult to maintain them since they take the pleasure out of eating. This can result in hunger, weight regain and the frustrating results of dieting failures.

What should you do either lose weight or improve your health? Commercial weight loss programs usually do not address the health aspects of diets; they only focus on weight loss. It is important to discuss your health profile with your doctor by looking at lipid and glucose lab results to decide which approach is best. People should choose their own diets based on their own personal metabolic profile, diet goals, and food preferences – think more of your health and less in terms of weight loss. Hopefully in the future, the diet wars will be resolved with more knowledge about the complexity of weight loss, weight maintenance as well as diet and health.

Perhaps, it may be best to not “diet” at all – more on this approach later.

 

 

 

 

 

 

 


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Ancel Keys – Big Fat Confusion?

An early picture of Ancel Keys, This image is ...

An early picture of Ancel Keys, (Photo credit: Wikipedia)

Time Magazine 1961. Ancel Keys appears on the cover to claim that saturated fat in the diet clogged arteries and caused heart disease.

Time Magazine, 2014. Eat Butter. Scientists were wrong about saturated fat. They don’t cause heart disease.

How did the low saturated fat message begin?  How, when and why did this confusion begin?

Ancel Benjamin Keys was born in 1904 in Colorado Springs, Colorado to teenage parents. In his younger years he had various jobs including a clerk in a Woolworth store. He finished college in 3 years with Honors at Berkeley and earned a MS in Biology followed by a PhD from the Scripps Institute of Oceanography. In 1930 he traveled to Copenhagen to work with Nobel laureate, August Krogh where he studied the ability of eels to survive in both fresh and salt-water environments. He then went to Cambridge and obtained a second PhD in animal physiology from King’s College.

He married a biochemist, Margaret, in 1939 and established the Laboratory of Physiologic Hygiene at the University of Minnesota.   It was this year that “he came to the attention of the United States War Department and was asked to develop and test food rations for parachute troops.” The result was the K ration, which became standard fare for feeding troops in World War II. Journal of Clinical Lipidology, (2011) 5, 434-437.

What made Keys famous was his Seven Countries Study, a study that remains controversial to this day. He initially observed that heart disease rates dropped in countries forced to alter their high fat diets because of the war rationing and reversed to higher rates when these diets returned.

He suspected dietary factors, particularly saturated fat, that might play a key role in atherosclerosis. After conducting some well-designed studies to support his theory, “he formulated an equation that simply showed a 2.7% mg/dl rise in cholesterol for every 1% of calories derived from saturated fat. The equation also suggested that polyunsaturated fat lowered serum cholesterol and dietary cholesterol raised serum cholesterol but to a lesser extent than saturated fat. “ Journal of Clinical Lipidology, page 435

Keys had based his theory on when he had previously visited Italy and Spain. He observed in Naples, Italy that only heart disease patients in hospitals were wealthy men. In Madrid, Spain he took blood samples from some men in one of the poorer districts where heart disease was rare and compared them to samples of more well-off patients with heart disease. What he found were differences in their serum cholesterol values with the higher levels in the wealthy and lower values in the poorer population. The diets of the two groups also differed with the poorer diets lower in fat than those of the wealthy. These observations were central to his theory that saturated fat or animal fat and dietary cholesterol contributed to heart disease.  Levenstein, Harvey, Junk Science Week: Lipophobia and the Bad Science Diet, Financial Post, June 11,2012.

The theory gained some steam when in 1955, President Dwight David Eisenhower had a heart attack at age 64, “ Over the next six weeks, twice-daily press conferences were held on his condition. After his attack, he dieted religiously with a low-fat diet and had his cholesterol measured ten times a year (it had been 165 mg initially)”. Taubes, Gary. Good Calories, Bad Calories, page 1-4.   The low-fat diet had little effect and his cholesterol continued to rise as well as his weight.

Between 1955 and 1958, Keys began to study the male population aged 40 to 59 in rural areas in certain countries. He used electrocardiograph data to detect heart abnormalities and cardiovascular disease. The countries included Yugoslavia, Italy, Greece, Finland, the Netherlands, the U.S. and Japan. The countries he had chosen represented varied intakes of saturated or animal fat; lower levels were found in some populations in Yugoslavia, Italy, Greece, and Japan. Finland, the Netherlands, and the U.S. represented higher levels of animal fat in their diets. Five and ten years later, the researchers returned to identify those who had experienced heart attacks. The lowest rates were found in Crete and Japan with the lowest levels of animal fat; the highest was found in East Finland and the U. S. with the highest levels of animal fat. All in all, Keys studied nearly 13,000 men.  From this study, he concluded that “saturated fats as a percentage of calories was the most powerful lifestyle predictor of heart disease. “Blood cholesterol was the important physiological variable. “ Journal of Clinical Lipidology, page 437.

In 1961 Keys appeared on the cover of Time magaine with the Seven Countries Study’s alleged link between fat, cholesterol and heart disease that fueled the fear of dietary fat in America. Two weeks later the American Heart Association (AHA) endorsed the theory.  With this announcement, the vegetable oil producers could not get their advertisements out fast enough. Wesson Oil said: “polyunsaturated Wesson is unsurpassed by any leading oil in its ability to reduce blood cholesterol.” Nutrition scientists jumped on the bandwagon. For example, Harvard nutritionist, Frederick Stare advised swallowing three tablespoons of polyunsaturated oil each day. Lipophobia had begun in earnest. Levenstein, Harvey, Lipophobia and the bad science.

Consumption of margarine doubled from 1950 to 1972 and that of vegetable oil rose by over 50% in the 10 years from 1966 to 1976. Ironically, based on the thesis of Keys that saturated fat was the culprit, the AHA and other agencies had urged food processors to use trans fats to replace the alleged deadly saturated fat. Ironically, the most common source of trans fats turned out to be the very margarine they had promoted as heart healthy. From 1956 to 1976, per-capita butter consumption fell by over half.

Key’s hypothesis strengthened in 1977 with Senator George McGovern’s publication of the First Dietary Goals for the U.S., which was the first time that any government group had told Americans to eat less fat and cholesterol to improve health. The document became gospel and had a tremendous impact on consumers and the food industry. In 1980, Hegsted and McGinnis produced the USDA Dietary Guidelines for Americans that concurred with “avoiding too much fat and cholesterol and eating more foods with adequate starch and fiber.”

However, three major studies failed in their support for Key’s hypothesis and without going into the details, each one raised doubts about the  hypothesis. The studies were the Women’s Health Initiative (WHI) in 1991, the Multiple Risk Factor Intervention Trial (MRFIT) in 1982, and the more recent LOOK AHEAD Study. Ironically in 1989, Frederick Stare from Harvard University, who had originally supported the Keys thesis, reversed his opinion and joined the opposite camp of doubters by co-authoring a book entitled Balanced Nutrition: Beyond the Cholesterol Scare.

The Key’s Seven Countries Study, so pivotal in lipophobia has been debunked by many, particularly those who favor the idea of eating meat.. On the other hand, vegans favor the thesis. Here is what the critics of the study say: First, Keys did not randomly choose countries but is accused of picking those countries most likely to support his theory. He excluded France whose diet has been notoriously rich in saturated fat along with a low heart disease rate (The French Paradox). He also excluded Switzerland, Sweden, and West Germany with the similar higher saturated fat intakes but with lower rates of heart disease. He originally gathered data from 22 countries.   However, some point out that even when all 22 countries are analyzed, the trend that fat intake is associated with heart disease still weakly exists.

From his work with the GreeK islands, Crete and Corfu, Dr. Keys and his wife wrote two best-selling books, Eat Well and Stay Well and How to Eat Well and Stay Well the Mediterranean Way. These and a third book they wrote, “The Benevolent Bean,” had the kind of recipes on foods of the Mediterranean regions that Keys had studied. To their credit, their books were among the first extolling the virtues of the popular Mediterranean diet today. After living in Italy for many years and following his own advice, Ancel Keys died in November of 2004 at the age of 100 years old.

Key’s thesis is still hotly debated to this day because of its limitations and lack of  conclusive support from the research community. There are still adherents of the efficacy of the low fat diet, particularly in its effects on atherosclerosis regression or prevention.  The debate has now switched to which diet is heart healthy – a low-fat or a low-carbohydrate diet. However, that is another story.

I truly don’t know if Keys was right or wrong. The purpose of this post is to point out that his legacy remains as one of the leading food crusaders that changed the American plate.  Is the low fat craze finally coming to an end?  Has this national experiment failed?  Will the low carbohydrate diet help curb the obesity epidemic or prevent heart disease?  Sounds like a “soap opera, doesn’t it?  One thing is certain – atherosclerosis is a complicated disorder and until its origin and pathology is conclusively determined, no one will know who was right.

As Keys himself summarizes: “The direct evidence on the effect of diet on human atherosclerosis is very little…. but such evidence as there is, plus valid inferences from indirect evidence, suggests that a substantial measure of control of the development of atherosclerosis in man may be achieved by control of the intake of calories and all kinds of fats, with no special attention to the cholesterol intake”.   Human Atherosclerosis and the Diet, Ancel Keys, Circulation 1952; 5: 115-118.

According to David Katz. MD, Director, Yale University Prevention Research Center,   “For whatever it is now worth, to my read, Keys’ messages were mostly right, a bit wrong and horribly vulnerable to the distortions of mercenary marketing and mass gullibility”. David Katz, MD, MPH The Keys to Good Health, August 14, 2014.


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And the Winner Is???

English: A display of high fat foods such as c...

English: A display of high fat foods such as cheeses, chocolates, lunch meat, french fries, pastries, doughnuts, etc. Reuse Restrictions: None – This image is in the public domain and can be freely reused. Please credit the source and/or author listed above. (Photo credit: Wikipedia)

The diet debate continues!!!

There have been a couple of diet studies in the news this past week that need to be mentioned. The first one compared a low fat diet with a low carbohydrate diet for weight loss and cardiovascular risk factors.  (Effects of Low Carbohydrate and Low-fat Diets: A Randomized Trial, Annals of Internal Medicine 2014; 161(5): 309-318).  You can read the major findings of this study HERE.

I have read this study and found that the low carbohydrate group’s mean caloric intake was less than the low-fat group at each assessment period, (3, 6, and 12 months) indicating that they ate less food than the low-fat group.  This may have accounted for the differences in the effects on cardiovascular risk factors.  Nevertheless, the risk factor data is somewhat impressive.  Often we dwell only on diets and weight loss and not on the fact that some diets may be healthier overall  than others.  In this study, many of these parameters were positively affected more by the low carbohydrate diet than the low fat diet, primarily HDL-C, the so–called good cholesterol and blood triglyceride levels.    LDL-C, the so-called bad cholesterol was not affected by either diet.

Another study appeared in the Journal of the American Medical Association, entitled: Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults: A Meta Analysis. JAMA 2014; 312(9):923-933.  You can find the main findings HERE.

The conclusions were: Significant weight loss was observed with any low carbohydrate or low-fat diet. The median weight loss; at 12 months, it  was just over seven kilograms for both types of diets. Their results support the idea of recommending any diet that a patient will stick with in order to lose weight.

In other words, the diet chosen has to be one that is not so restrictive as to allow the follower to “go off the diet” and experience another weight loss failure. Every diet should be one that a person can live with for an extended period of time.  One obesity expert, Dr. Yoni Freedhoff says he doesn’t believe in weight loss by suffering and it is not sustainable over the long term.