Wednesday, September 14, 2005

Examining Low-Carb & Low-Fat Diets: Part 3

Part 3: Nutrient density by macronutrient type and how to increase your intake of essential nutrients to optimize health.

In this three part series looking at low-carb diets versus low-fat diets, I've discussed in Part 1 why the percentage of calories from fat is not a measure of quality in your diet. In Part 2 I compared, side-by-side, a very low-carb menu with a very low-fat menu and exposed the nutrient deficiency caused by decreased intake of fat and protein that is necessary to maintain macronutrient mix based on the recommendations for percentage of calories in the diet.

Today we'll explore the various macronutrients and why the focus must shift to nutrient-density from micronutrients and essential nutrients in the foods you eat and not the percentage of calories each day from macronutrients.

Let's start with protein.

For decades our dietary recommendations have undervalued protein in the diet, offering a recommended intake ranging from 10% to 35%, with intake levels set to balance intake of carbohydrate and fat. Not only that, but protein from plant sources is basically viewed as the same as protein from animal sources when it is not the same.

Yet if we look at the word "protein," we find that its origin is significant - French protéine, from Late Greek prōteios, of the first quality, from Greek prōtos, first.

Of first quality? First? Say what?

Something our ancestors understood all too well - protein is of utmost importance in our diet, something reflected in the root meaning of the word itself.

Why exactly is protein important?

Well, for one thing, the human body requires that we provide, through our intake of food, amino acids from protein sources. These amino acids are called "essential amino acids" because our body cannot make them from within. There are a total of twenty amino acids available from protein sources, of which eight are essential and two are conditionally essential. If you do not eat foods with adequate levels of the essential amino acids, you're failing to provide your body with what it requires to function and build and repair cells.

Proteins are involved in practically every function performed by cells, so why do we place such little value on it in our recommendations? In part, as stated by the Institute of Medicine (IOM) in their documentation for recommended levels of intake, While no defined intake level at which potential adverse effects of protein was identified, the upper end of the AMDR (acceptable macronutrient distribution range) [was] based on complementing the ADMR for carbohydrate and fat for the various age groups.

There you have it - to maintain the recommendation - the party-line - of no more than 30% of calories from fat, the recommendation for protein was established not on evidence and data, but to maintain the percentage of calories from fat and carbohydrate!

So what happens when you consume too little protein and thus too few essential amino acids? Protein deficiency can lead to symptoms such as fatigue, insulin resistance, hair loss, loss of hair pigment, loss of muscle mass, allergies, heart disease, low body temperature, and hormonal irregularities.

I can't stress this enough - protein is critical in your diet.

And not just any protein - you need a complete complement of all the essential proteins each day. Otherwise, you're unwittingly undermining your long-term health and vitality. As the Biology Project at the University of Arizona states in their documentation of amino acids, Failure to obtain enough of even 1 of the 10 essential amino acids, those that we cannot make, results in degradation of the body's proteins—muscle and so forth—to obtain the one amino acid that is needed. Unlike fat and starch, the human body does not store excess amino acids for later use—the amino acids must be in the food every day.

Why is it difficult to consume enough complete-quality protein when fat is limited?

Because the sources of complete-quality protein ALL contain fat and are virtually all animal sources.

Which brings me to the next macronutrient - fat - that our dietary recommendations insist must be limited to 30% or less of calories each day. Not only that, but no more than 10% of total calories are recommended from saturated fat.

Surely such a recommendation must be rooted in evidence that supports limiting fat intake?

Well, again, let's look at the IOM documentation statement: While no defined intake level at which potential adverse effects of total fat was identified, the upper end of the AMDR is based on decreasing risk of chronic disease and providing adequate intake of other macronutrients.

Did you catch that? The upper limit, 35% of calories from fat, is not supported by research evidence and data - but like the AMDR for protein, is set to maintain the party-line recommendations for macronutrients as a percentage of calories each day!

So, do we really need fat in our diet? Is it even reasonable to put forth contentions that having a higher percentage of calories from fat may be better in the long-term for health?

Like protein, we have dietary requirements for what are called essential fatty acids (EFA) that are provided in our food from fats within the food.

There are dietary requirements for two essential fatty acids - Linoleic Acid (LA) an omega-6 and Alpha Linolenic Acid (ALA) an omega-3.

As hundreds of studies over the last five years are bringing to light, we're consuming too much LA (omega-6) and not enough ALA (omega-3). And this is a direct consequence of the shift we've made in the last thirty years in not only how much fat we consume but what types of fat we eat.

Add to this, our increased consumption of foods that have removed or reduced fat and are promoted like skim milk and reduced fat cheese. Guess what? Whole milk, cream, half-and-half and natural full-fat cheese all have a balance of ALA and LA. Oh, and they're also sources of complete-quality protein too!

But I digress...

Why are EFA's so important? They support the cardiovascular, reproductive, immune, and nervous systems.

As Pam Rotella (a vegetarian I might add) states on her Essential Fatty Acids page: The human body needs EFAs to manufacture and repair cell membranes, enabling the cells to obtain optimum nutrition and expel harmful waste products. A primary function of EFAs is the production of prostaglandins, which regulate body functions such as heart rate, blood pressure, blood clotting, fertility, conception, and play a role in immune function by regulating inflammation and encouraging the body to fight infection. Essential Fatty Acids are also needed for proper growth in children, particularly for neural development and maturation of sensory systems, with male children having higher needs than females. Fetuses and breast-fed infants also require an adequate supply of EFAs through the mother's dietary intake.

So, like protein, our bodies require particular fats each day from our diet.

While many sites online promote the plant based and marine sources of ALA, they fail to mention its presence in animal fats, and play-down the often too high levels of LA in many oils promoted to reduce intake of saturated fat.

Remember, the research is showing that we need a balance of ALA to LA - anywhere from 1:1 to 1:4 is where the scientists currently stand on the issue of ratio in the diet. Do you know what our current average ratio is? 1:20

That's right, we're eating five-times the LA in our diet to ALA and the excess is believed to have negative effects on our health.

So what are good sources of ALA? Eggs, cream, fatty fish, fish oils, flaxseeds, flax oil, dark green leafy vegetables, cruciferous vegetables, root vegetables, red meats, cheese (natural) and a variety of nuts and seeds and even some spices like oregano and cloves. Yet many of these foods are avoided in our diet.

What happens if you're deficient in omega-3 or have a too high ratio of omega-6 to omega-3? The symptoms of omega 3 fatty acid deficiency or omega-6 excess include fatigue, dry or itchy skin, brittle hair and nails, constipation, frequent colds, depression, poor concentration, lack of physical endurance, and/or joint pain.

In our efforts to reduce fat intake and avoid saturated fats, we've skewed our intake ratios of omega-3 and omega-6 and in the process also increased our intake of a deadly man-made fat found in partially hydrogenated fat - trans fatty acids.

As Dr. Mary Enig states in her paper, Health Issues and Trans-fats, [b]ecause trans fatty acids disrupt cellular function, they affect many enzymes such as the delta-6 desaturase and consequently interfere with the necessary conversions of both the omega-6 and the omega-3 essential fatty acids to their elongated forms and consequently escalate the adverse effects of essential fatty acid deficiency.

She continues by adding, The fats that humans have consumed for millennia, such as the fats that they added to mixed dishes, were almost always more saturated than they were unsaturated. It was the easily extractable fat or oil, the fat that came from the animal, or, in the case of areas such as the tropics, it was the oil that came from the coconut or the palm fruit that was used in cooking. Sometimes it was one of the very stable oils like olive oil (or sesame paste) that had a lot of built-in antioxidant and wasn't too polyunsaturated.

People didn't really have the ability to extract oil from vegetables like corn, or from many seeds as they do today. However, they got their essential polyunsaturated fatty acids from many of these plants when they were included in the foods they were eating. People used the intact leaf, root, nut, grain or seed along with all its antioxidants in the stews or the porridges that most people ate. This was the way the polyunsaturates were historically consumed. The polyunsaturated fatty acids didn't have to be hydrogenated to protect their integrity and keep them from going rancid because they were consumed in a protected whole-food state.

It is only in modern times that we avoid saturated fats and consume oils that are high in omega-6 and man-made trans-fats. The question begs - why? Why not eat a full range of foods, whole foods, including those that may be higher in saturated fat to unsaturated fat?

Which brings me to the real issue - we've migrated away from our traditional dietary habits of eating real whole foods - which included natural fats and oils - and now consume much more processed packaged food, highly refined food and convenience food - which includes man-made trans-fats, chemicals, added sugars and less essential, critical nutrients.

And so we're back to nutrients.

We're told that we must consume a high percentage of our diet from carbohydrate foods to meet our essential nutrient requirements. Funny thing here is that unlike protein or fat, we have no essential requirement for "carbohydrate" - what we require are vitamins, minerals and trace elements - found in various foods we eat.

Here is something that is not so funny - if we eat a diet that provides adequate intake of our essential amino acids and our essential fatty acid requirements, we often meet or exceed our requirement for vitamins and minerals too - with or without carbohydrate foods like grains, fruits and starchy vegetables.

We've been fed a package of "big fat lies" when it comes to our nutritional requirements. The focus has been, for the last three decades, to reduce fat intake. The consequence is that we've listened, we consume less fat, less saturated fat and eat much more carbohydrate than ever before. Yet, we remain - I contend - malnourished...starving for our essential nutrients because we are not eating a "balanced diet" to provide our essential nutrients and instead have focused on the wrong formula - percentage of calories from macronutrients each day.

We can reverse our trend of obesity, diabetes, heart disease, cancer and other chronic disease IF we start paying attention to and focus on what the human body REQUIRES for health - EFA's, EAA's and Vitamins, Minerals and Trace Elements. At the end of the day, it matters little what your percentage of fat is if you fail to meet your requirements for EFA's, matters little if you fail to meet your requirements for EAA's, and matters even less if you also fail to meet your requirements for essential micronutrients.

The experts claim that a "balanced diet" that is "nutritionally complete" is one where the macronutrient ratios are 30% or less fat, 15% protein and 55-65% carbohydrate. Where is the evidence to support this? Where is just one menu that proves you can meet or exceed your essential nutrient requirements within this ratio and the menu is whole foods based and one you would want to eat? Where is the long-term data to prove that this dietary pattern, over the long-term, improves your health and well-being?

Yesterday I showed a simple, very low-carb menu, created without professional training in nutrition or access to powerful menu-planning software, met or exeeded nutrient requirements, while the menu created by those considered to be "experts" failed miserably.

Yet we're told that this failure menu is "balanced," "healthy," and "nutritionally complete." On what planet?

Folks, I strongly recommend that before you embark on any dietary change - stop and evaluate the nutrient-density of the menus you're given and told to follow. If the menu is failing to meet your essential nutrient requirements, find a different approach. The long-term consequences of nutrient deficiency are disease and degradation in the body...the exact opposite of what you want to achieve for long-term health and well-being.

To lose weight, a low-carb approach can and does dramatically change your nutrient profile - for the better. Depending upon your food choices on a very low-carb approach, you may or may not need a vitamin supplement while you're losing weight - the same can be said of any calorie-restricted diet. I do recommend one as a "safety net" while you're losing weight even though meeting your nutrient requirements is possible on a very low-carb plan and impossible - that's right impossible - on a low-fat diet.

Over the long-term a controlled-carb approach maintains a nutrient-dense profile for optimal health. The key is real food - whole food - from a wide variety of food options.

4 comments:

  1. I take offense to your claims that Low Fat isn't based on healthy, natural/whole foods.

    I have lost a lot of weight following a Low Fat diet and I've been able to maintain that weight loss for over 6 years. The type of Low Fat diet I followed (and the type that any credible health professional would recommend) is centered on a plant-based diet consisting of fruits, veggies and whole grain products. Aren't those natural/whole foods?

    Sure there are packaged/processed products on the market, being marketed as Low Fat, but you won't find many credible health professionals associated with a Low Fat lifestyle who would recommend these as part of a legit Low Fat diet.

    Also how come your entry makes no mention of the packaged/processed Low Carb foods on the market, such as Atkins Advantage Bars or Low Carb candy bars?

    Aren't these also unhealthy, packaged processed foods?

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  2. Tony - thank you for your comments.

    I'd love to see one of your menus and would be happy to assess it for nutrient-density from just your food and beverage intake. Feel free to email me a typical day with how much of each food you consume at controlledcarb@aol.com

    To answer your question about whole foods in a low-fat diet - the current recommendations point to low-fat/skim milk (processed to remove fat), reduced/low-fat cheese and yogurt (made from milk that has had fat removed) so none of these are the original "whole food" they started as. Many of the low-fat products promoted as "healthier" are often loaded with added-sugars to improve mouth-feel of the end product and are often from companies that are in the "health food, natural food" sector!

    If you've read through my blog, you'd know I strongly encourage consumption of 100% whole grains, fruits, vegetables, nuts, seeds and legumes too to round out a long-term controlled-carb approach. In fact, I contend that the largest volume of food eaten daily when one is following a controlled-carb approach should be non-starchy vegetables!

    Lastly, regarding the low-carb products - if you'd read part 2 of the series, you'd have seen that I said - quite clearly - to avoid them "skip the processed foods touted as "low-carb" - you don't need them!"

    Thanks again for stopping by!

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  3. Thanks for you`r blog about healthy food.

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  4. This is really a fascinating blog, lots of stuff that I can get into. One thing I just want to say is that your Blog is so perfect!

    ReplyDelete