Friday, February 15, 2013

Is a Low-Fat Diet Healthiest?

In the last two blogs I tried to correct the (dangerous) misunderstanding many Americans have regarding high-protein diets.  Today I focus on the confusion many people have about low-fat diets.

Americans have focused ad nauseam on low-fat diets.  Now overwhelming evidence indicates that it is the type of fat that matters, not the amount.  Traditional Greeks, arguably the healthiest people on the planet measured by low rates of premature mortality, ate a 40% fat diet based predominantly on olive oil.  Americans are shocked to hear that such a “high” fat diet actually lowers triglycerides.  In recent years the American Heart Association has “tweaked” its recommendation upwards from 20 to 30% fat.  The National Cholesterol Education Program’s cholesterol-lowering diet (p. V-2) has been revised to 25-35% fat with an emphasis on plant fat.

Yet due to decades of low-fat recommendations based on nutrition research which at first glance seemed to indicate that a low-fat diet would prevent cardiovascular disease, and due to the plethora of low-fat products which subsequently flooded the market with their “nutrition education” influence on the American public, many Americans still think that eating a low-fat diet is the “healthiest” way to live.  However, overwhelming evidence indicates that a moderate fat diet is much healthier.  Actually, a diet that would be considered high-fat (40%) in comparison to previous recommendations (20%) actually reduces the incidence of cardiovascular disease.  The 7 Countries Study performed way back in the 1960’s by T. Ancel Keys found that the diet eaten by the Greeks on the island of Crete was one of the highest fat diets at 40% fat, low in saturated (or animal) fat and high in monounsaturated fat (from plants), but the Greeks eating it came out with some of the lowest rates of cardiovascular disease and all-cause mortality and had the longest life expectancies in the world at that time.  The diet, now fondly called the “Mediterranean Diet” is high in vegetables (about 2-3 cups/day), especially green leafy types, high in fruits (2-3 /day), high in wholegrain carbohydrates (equivalent to 8 servings/day), high in legumes and nuts, moderate in fish and alcohol, low in meat and fermented milk products.  The diet is also low in animal and saturated fat but high in total fat (40%) with 4 Tbsp. olive oil/day. 

So how was it that American nutrition experts originally came to the low-fat conclusion? 

Wednesday, February 6, 2013

The Harms of a High (Animal) Protein Diet: Part 2

The Problems with High Animal Protein Diets

Continuing from the previous blog, recall that a three-pronged approach to prevent the metabolic syndrome seems prudent—weight-lossexercise, and incorporating anti-inflammatory foods in a plant and fish based diet.  Recall also that there is more harm than good in trying to follow the weight-loss recommendation with a high-protein diet.  To continue the list of harms:

·   In the American diet, animal protein (but not plant) is usually linked with saturated fat and cholesterol, which increases LDL-cholesterol (an effect that is compounded when high-carbohydrate, high-fiber plant foods are limited).  It is generally recommended that 10% or less of your total daily calorie intake come from saturated fat, whereas a high-protein diet can have as much as 25% saturated fat.

·   Increased homocysteine levels in blood (a by-product of animal protein breakdown) have been associated with increased risk for cardiovascular disease.  Hospitals now routinely test for homocysteine.

·   Excess animal protein (but not plant) can crowd out a sufficient intake of protective fruits, vegetables, whole grains, beans, nuts and seeds.  High-protein diets are carbo-phobic.  Many high-protein diets intentionally restrict fruit, vegees, beans and whole grains, further reducing your intake of health-supporting, disease-preventing phytochemicals.  Most high-protein diets are based on 30-40% calories from carbohydrates whereas a healthy diet is based on 45-65% calories from nutrient-rich, fiber-rich carbohydrate foods. 

· High-animal-protein diets are low in fiber which can cause constipation and diverticulitis.

·  A high animal protein intake usually means a lower carbohydrate intake.  Since carbohydrates are the “high energy nutrient”, the first source of energy the body uses for fuel, high-protein (low carb) diets often result in fatigue, and sometimes headaches (due to low blood sugar and/or dehydration).

·   Dietary animal protein sources are usually expensive.

·   A high-carbohydrate diet including fruit, vegees, whole grains, and nonfat dairy products has been shown to decrease blood pressure.  Limiting these foods may increase blood pressure as potassium, calcium, and magnesium are decreased and sodium is increased. 

·   Strong evidence has accumulated indicating harmful “meat factors” promote cancer.  Restricting fruit, vegees, beans and whole grains reduces your intake of health-supporting, disease-preventing phytochemicals which further increases your risk of cancer.

·   High animal protein diets (but not plant) increase urinary calcium losses, contributing to osteoporosis and kidney stones.

·   High-protein foods such as meat, poultry, seafood, eggs, seeds and nuts are high in purines.  An excess of purines may cause gout in susceptible individuals.

·   People with liver or kidney disease are at increased risk on high-protein diets.  High-protein diets can increase your chances of developing kidney disease, especially in diabetics, because of the high level of protein which puts a strain on the kidneys.  A very high-protein diet, even for short lengths of time, can speed progression of diabetic renal disease.

·   High-protein diets can result in a dangerous metabolic condition called ketosis.  The body normally   burns carbohydrates first for energy.  High-protein diets that are low in carbohydrates force the body to burn fat for energy instead.  The by-product of fat breakdown are substances called ketones.  The very low-carbohydrate intake required in the first “phase” or weeks of many high-protein diets leads to a state of ketosis in which a large amount ketones accumulate in the body.  Ketosis occurs in uncontrolled diabetes (as when a diabetic does not have the necessary insulin), which can lead to coma and death, and in eating disorders (as a result of starvation).  High-protein diets put individuals in a similarly "sickened" state.

·   A high-protein diet can lead to or exacerbate dehydration.  Protein has nitrogen, which breaks down to ammonia, and must be diluted by the body.  Additional water is necessary to remove nitrogen from the body via urine. 

Is it any wonder high-protein diets cause health problems?  Yet even given all of these facts, and the physiological problems and recidivism rate of these popular diets, the high-protein diets continue to be popular because they “tickle the ears” of an American public wanting a quick fix to their problems without making real change.  Americans typically eat 2 1/2 times the amount of protein physiologically necessary.  The message of the high-protein diet authors to Americans—you can have your steak and eat it too.  Sorry, but some things really are too good to be true. 

The fact is despite the reported physical harm and weight-regain experienced by high-protein dieters, because of the insane popularization of the high-protein diets in the media (and I include food product advertising in that) many people now think that a high-protein (carbo-phobic) diet is the best way, even a healthy way, to lose weight.  The recommendation to lose weight to resolve the metabolic syndrome which 1 out of 3 Americans now suffer will likely result in masses of well-intentioned people going on high-protein diets, which will make their metabolic problems (and America’s already epidemic health crisis) worse.  Many Americans will unknowingly be led to slaughter even more willingly because many of the diet books give mention to the metabolic syndrome (often with interesting but not completely correct discussions about insulin and blood sugar) to support their dietary claims. 

The combination of the power of the media to promote high-protein diets and the “success” of quick visible weight-loss on high-protein diets has convinced many Americans that they are healthy.  A big part of the problem is the incessant value we put on weight-loss in America so that we have fallen for yet another false solution.  The bottom line is the public needs to be aware that there are two ways to lose weight—healthy and unhealthy—and wellness professionals need to be careful to not indiscriminately promote treatment for the metabolic syndrome with “weight-loss and exercise” without explaining that vital distinction clearly to patients. 

Let’s do this right,

Diane Preves, M.S., R.D.

N.E.W. LIFE I/ copyright 2013

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Monday, February 4, 2013

The Harms of a High (Animal) Protein Diet: Part 1

Continuing from the last blog discussion on the metabolic syndrome . . .

Recall from the last blog that the Center for Disease Control reports that 1 in every 3 Americans suffers with the metabolic syndrome—a silent killer that leads to cardiovascular disease and diabetes.  The metabolic risk factors that result from the “hyperinsulinemia” (high amount of insulin pumped out of the pancreas to overcome the “insulin resistance” of the cells) include abdominal obesity (waist circumference > 40” in men, > 35” in women), triglycerides > 150 mg/dL, low HDL cholesterol (< 40 mg/dL in men, < 50 mg/dL in women), high blood pressure > 130/85 mm Hg, and fasting glucose > 110 mg/dL.  If you have just 3 of the symptoms you are diagnosed with metabolic syndrome and are at significantly higher risk for developing a heart attack or diabetes if you do not resolve the syndrome.  Also associated with the syndrome is the presence of small (dense) LDL cholesterol and inflammation.  Certainly we need to know what we can do to prevent the onslaught of this disease in Americait is preventable.  

The two recommended treatments which have the ability to reduce the risk factors and resolve the metabolic syndrome are weight-loss and exercise, both with anti-inflammatory results.  Recently there has also been a lot of discussion about the anti-inflammatory properties of certain components of many healthy foods such as the omega-3 fatty acids (in fish, walnuts and flaxseed), antioxidants (in fruits and vegetables), and a component in olive oil, as well as soluble fiber and selenium.  Therefore, a three-pronged attack to prevent the metabolic syndrome seems prudent—weight-loss, exercise, and incorporating anti-inflammatory foods in a plant and fish based diet.  Today I focus on a big concern I have regarding the weight-loss recommendation.

When you hear “weight-loss” what do you think of?  Many Americans automatically think of a diet and, if that wasn’t bad enough, they almost as automatically think that a high-protein diet is a good “healthy” solution.  But nothing could be further from the truth.  I hope you have heard by now that high-protein diets are not safe, but if you are still of the opinion that they are, read on. . .

Friday, February 1, 2013

Metabolic Syndrome Diet Recommendations

Recall from the last blog that the metabolic syndrome is a condition that has exploded in the American population in the last few years (the CDC estimates that 1 out of 3 American adults meet the criteria for metabolic syndrome) and that the syndrome is diagnosed when an individual has 3 of the following risk factors: high waist circumference (abdominal obesity), high triglycerides, high blood pressure, low HDL (good) cholesterol, high-normal blood sugar.   Recall also that individuals that have the constellation of risk factors that comprises the metabolic syndrome are at significantly higher risk of developing cardiovascular disease and/or diabetes.  The metabolic syndrome, which also goes by other names (Syndrome X, insulin resistance, pre-diabetes, hyperinsulinemia) is resolvable with weight-loss and exercise. 

The effectiveness of the traditionally-recommended high-carbohydrate diet (55-65% carbs) for cardiovascular disease came into debate because of the evidence that at least 10-30% of the population may be "hyperinsulinemic” (they have an overproduction of insulin in response to carbohydrates) resulting in the now widely recognized Syndrome X.  Here’s how it works--             

After we eat, blood sugar level rises triggering the pancreas to secrete the hormone insulin which stimulates the body’s cells to take in and store glucose, or use it for energy.  In insulin “resistant” people, the cells become less and less sensitive to insulin, so the body pumps out more insulin (hyperinsulinemia) to do the job of getting sugar into the cells.  The excess insulin manages to keep blood glucose levels within the normal range, though usually at the upper end (called “high-normal” glucose or “impaired glucose tolerance”) so diabetes does not occur (yet).  In years past this was often overlooked by doctors, but in reality the steadily rising blood glucose measures year after year (if it was even measured at all) was often an indication that more and more insulin was being produced in an effort to keep “pushing down” the steadily rising blood sugar level.  The gradual but steadily rising blood glucose was a sign that insulin was losing the battle and having to call on more and more insulin to do the job (hyperinsulinemia).  But the patient could go home with a pat on the back that he was not, at least yet, diabetic as often other family members were (the reason for testing blood sugar in the first place, also the reason for the "good news" that blood sugar was still in the "healthy" range for this patient).  Silently, however, the consistently increasing insulin had its own metabolic cascade of effects as the blood sugar slowly climbed its way up to diabetes diagnosis anyway.  That metabolic cascade is now widely recognized as Syndrome X or metabolic syndrome, the common cluster of disordered symptoms described above (in red) which contribute to increased risk of cardiovascular disease and diabetes.

The CDC confirmed in a 2011 Diabetes Fact Sheet that in 2005−2008, based on fasting glucose or hemoglobin A1c levels, 35% of U.S. adults aged 20 years or older had    pre-diabetes (50% of those aged 65 years or older).

One more important note (to be continued in the next blog)—while the the Mediterranean and Syndrome X diets are lower carb (45%) than the traditionally recommended higher carbohydrate diets of the past (55-65%), they are not low carbohydrate diets.  The popular high-protein (carbo-phobic) diets recommended in many recent popular diet books are based on 30% carbs which is way too low, the physiological reasons (i.e., inducing a state of ketosis) to be discussed in a future blog.  These diets are to be avoided, at all cost (or it will cost you).  There is a kernel of truth in the high-protein diet proponents’ claims that carbohydrates in the diet are problematic.  However, they neglect to distinguish between the real culprits, simple carbohydrates, and healthy complex carbohydrates. 

It is the simple carbohydrates which Americans consume in excess that are known to affect insulin and inflammation, and there is no evidence that complex carbohydrates are to blame.

You'd never know that from the carbo-phobia which persists in the culture.  In insulin resistant individuals refined carbohydrates should be replaced with monounsaturated fats (as in the 40% fat Syndrome X diet and Mediterranean diet of the traditional Greeks based predominantly on olive oil).  Refined carbohydrates should not be replaced with protein (as in popular high-protein diets) because protein stimulates insulin secretion (recall that hyperinsulinemia is the problem!).  Monounsaturated fats do not stimulate insulin secretion and do lower triglycerides.  Furthermore, the Standard American Diet is already based on a preponderance of animal protein accompanied by saturated fat and cholesterol which raises the risk for cardiovascular disease further.

The high-protein diet self-professed “experts” (book authors) got a kernel of the truth right (replacing excess refined carbs) but in the not-too-long run are critically wrong!

All the best-selling anti-carbohydrate diet books cite the work of Gerald Reaven, and they all misinterpret that work, says Reaven, so he wrote his own book to combat the misinformation.  If you want to know the truth about Syndrome X, read Reaven’s book:

“I wrote the book because I got so upset about the misinformation in the other books,” he explains.

Let’s get this right!

Diane Preves, M.S., R.D.

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