Wednesday, July 09, 2008

John Berardi - A Balanced Diet Just Isn't Enough

Another great article from Dr. Berardi over in the forums of his Precision Nutrition site. I repeatedly tell my clients that it's much more difficult than they might think to get a nutritionally complete diet. This article takes a look at the issue, including some good research.

Here is the first part of a rather long and informative article:
A Balanced Diet Just Isn't Enough
by John M Berardi, PhD, CSCS

What The Heck Is A Balanced Diet?
You hear it all the time - from your mom, from dietitians, from doctors, from coaches, heck, even from your uncle Jimmy.

Just eat a "balanced diet" and you should be fine.

Of course, the fact that no one ever mentions what actually constitutes a "balanced diet" only adds to the mystique and allure of this mythical creature.

To your mom, a balanced diet pretty much means whatever she puts on your plate. To your dietitian and doctor, it pretty much means to eat less saturated fat and cholesterol. To your coach, it means whatever keeps you from getting fatter. And to your uncle Jimmy, it means skipping breakfast, having fries and a burger for lunch, and having a 6-pack of Coors Light after work.

For most people, a balanced diet is simply a buzz word for "eating whatever I want to eat." The phrase is beautifully vague enough to be able to justify their own personal choices with amazing vehemence and rationalization. It's vague enough to convince folks that no changes are necessary in their daily intake. It's vague enough for dietitians to suggest that no supplements are required to meet our daily needs.

Yet it's also vague enough to be utterly useless and void of all utility or meaning. And it's vague enough to ensure that the rates of diabetes and heart disease consistently increase.

Truth be told, as you've probably guessed by now, I hate the phrase "balanced diet." Indeed, if there were one phrase that should be banned from our collective nutritional lexicon, this is the one. It's a useless term that is often used to justify counterproductive habits.

How About A Dietary Analysis
To help illustrate my point, just the other day I was searching the medical databases for a host of diet analysis studies.

My goal was to find studies done on athletes, recreational exercisers, and sedentary folks.

And my intention was to find out whether or not their so-called "balanced diets" were actually providing them with the minimum level of nutritional intake established by the very conservative American Dietetics Association.

You see, the ADA establishes nutrition standards for the population at large.

For example, assuming a 2000kcal diet, the average person should be getting the following macronutrients each day, according to the ADA:
Total Fat 65 g
Saturated fatty acids 20 g
Cholesterol 300 mg
Sodium 2400 mg
Potassium 4700 mg
Total carbohydrate 300 g
Fiber 25 g
Protein 50 g
And in terms of micronutrients, here's what we should be getting to achieve 100% of our recommended daily intake, according to the ADA.
Vitamin A 5000 IU
Vitamin C 60 mg
Calcium 1000 mg
Iron 18 mg
Vitamin D 400 IU
Vitamin E 30 IU
Vitamin K 80 μg
Thiamin 1.5 mg
Riboflavin 1.7 mg
Niacin 20 mg
Vitamin B6 2 mg
Folate 400 μg
Vitamin B12 6 μg
Biotin 300 μg
Pantothenic acid 10 mg
Phosphorus 1000 mg
Iodine 150 μg
Magnesium 400 mg
Zinc 15 mg
Selenium 70 μg
Copper 2 mg
Manganese 2 mg
Chromium 120 μg
Molybdenum 75 μg
Chloride 3400 mg
Again, these numbers are conservative. They've been established by the ADA as rock-bottom minimums required to prevent us from contracting nasty diseases.

They say nothing about optimization, mind you. However, they are still useful. After all, if we dip below these levels, we're in nutritional deficiency land. Cue up pirate songs, eye patches, and the talk of scurvy.

So, in beginning the research review mentioned above, my goal was to uncover some of the published literature, to see if anyone ever actually achieves a "balanced diet" in the real world.

My criterion, of course, would be something measurable. I'd be using a real dietary analysis to determine just what "balanced" actually meant.

My Experience
Now, my experience told me that I'd be pretty disappointed in this notion of a so-called "balanced" diet.

When at the University of Western Ontario working on my PhD, I assisted Dr Peter Lemon with an advanced Exercise Nutrition course. And, as part of the class, every year we had 150-200 students do a personal dietary analysis.

So, for 3 years straight, it was my job to collect these analyses and plug them into a database for further review. And, over the course of 3 years, and over 500 exercise and nutrition students, it was my experience that very, very few of them achieved 100% of the recommended intake of all the macro- and micro-nutrients.

In general, only about 10-15% of them met all of their dietary needs. The other 85-90% were deficient in one or more key nutrients - whether it was zinc, magnesium, omega 3 fatty acids, or protein.

Interestingly, in my hunt above, I found an interesting study published in 2006. This study, published in the Journal of the International Society of Sports Nutrition, corroborated my experience perfectly.

Here's what the researchers found.
Read the rest.

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