The Final Word on Protein

20 02 2013

layne38I’ve been getting a bit of flak lately about the dietary protein intake that I’ve been recommending. Somebody recently said to me that they read that we can only absorb 30 g of protein per meal, so eating more is a waste. This information is false.  In my research to back-up my claim, I came across an article from 2009 on the Precision Nutrition website. This article tackles the protein consumption issue and hammers home the point that I’ve been trying to make: the human body needs protein; not just for muscle synthesis, but for countless other metabolic functions.

Please feel free to read the article, but to summarize:

Two studies were conducted in 2009 with respect to protein intake.  Both studies showed that muscle protein synthesis was stimulated maximally in the 20-30 g range, regardless of higher protein consumption rates. I assume that this is where the myth about 20-30 g per sitting began.

However, before jumping to conclusions, should we consider that maybe the extra protein was actually being used by the body in other productive ways (aside from muscle synthesis)?

Look at the results from a different angle an ask yourself the following questions:

1) What else will you eat? Carbs? Remember that not only do carbs spike insulin like crazy, but they have a lower thermic effect than protein (more on this below). If you’re loading up with excessive carbs, not only will your body composition suffer, but your health will deteriorate over time due to constantly elevated blood sugar (i.e. diabetes). Fats and protein should almost always make up the majority of your caloric intake.

2) What about the other benefits?:

Increased thermic effect of feeding — While all macronutrients require metabolic processing for digestion, absorption, and storage or oxidation, the thermic effect of protein is roughly double that of carbohydrates and fat. Therefore, eating protein is actually thermogenic and can lead to a higher metabolic rate. This means greater fat loss when dieting and less fat gain during overfeeding/muscle-building.

Increased glucagon — Protein consumption increases plasma concentrations of the hormone glucagon. Glucagon is responsible for antagonizing the effects of insulin in adipose tissue, leading to greater fat mobilization. In addition, glucagon also decreases the amounts and activities of the enzymes responsible for making and storing fat in adipose and liver cells. Again, this leads to greater fat loss during dieting and less fat gain during overfeeding.

Metabolic pathway adjustment – When a higher protein (20-50% of intake) is followed, a host of metabolic adjustments occur.  These include: a down regulation of glycolysis, a reduction in fatty acid synthesis enzymes, increase in gluconeogenesis, a carbohydrate “draining” effect where carbons necessary for ridding the body of amino nitrogen is drawn from glucose.

Increased IGF-1 — Protein and amino-acid supplementation has been shown to increase the IGF-1 response to both exercise and feeding. Since IGF-1 is an anabolic hormone that’s related to muscle growth, another advantage associated with consuming more protein is more muscle growth when overfeeding and/or muscle sparing when dieting.

Reduction in cardiovascular risk — Several studies have shown that increasing the percentage of protein in the diet (from 11% to 23%) while decreasing the percentage of carbohydrate (from 63% to 48%) lowers LDL cholesterol and triglyceride concentrations with concomitant increases in HDL cholesterol concentrations.

Improved weight loss profile —Research by Layman and colleagues has demonstrated that reducing the carbohydrate ratio from 3.5 – 1 to 1.4 – 1 increases body fat loss, spares muscle mass, reduces triglyceride concentrations, improves satiety, and improves blood glucose management.

Increased protein turnover — All tissues of the body, including muscle, go through a regular program of turnover. Since the balance between protein breakdown and protein synthesis governs muscle protein turnover, you need to increase your protein turnover rates in order to best improve your muscle quality. A high protein diet does just this. By increasing both protein synthesis and protein breakdown, a high protein diet helps you get rid of the old muscle more quickly and build up new, more functional muscle to take its place.

Increased nitrogen status — Earlier I indicated that a positive nitrogen status means that more protein is entering the body than is leaving the body. High protein diets cause a strong positive protein status and when this increased protein availability is coupled with an exercise program that increases the body’s anabolic efficiency, the growth process may be accelerated.

Increased provision of auxiliary nutrients — Although the benefits mentioned above have related specifically to protein and amino acids, it’s important to recognize that we don’t just eat protein and amino acids — we eat food. Therefore, high protein diets often provide auxiliary nutrients that could enhance performance and/or muscle growth. These nutrients include creatine, branched chain amino acids, conjugated linoleic acids, and/or additional nutrients that are important but remain to be discovered.  And don’t forget the vitamins and minerals we get from protein rich foods.

about-protein

Looking over this list of benefits, it’s hard to ignore the fact that we don’t just need protein for its effect on muscle synthesis.  Since a higher protein diet can lead to a better health profile, an increased metabolism, improved body composition, and an improved training response, why would anyone ever try to limit their protein intake to the bare minimum?

In conclusion: For optimal cellular function and healthy body composition you should aim for 0.7-1 g of protein per pound of body weight each day. This intake will make sure that you’re getting enough protein to reap all the benefits that this macronutrient has to offer, including but not limited to the muscle-building benefit. If you would like to lose some weight and tone up your body, try substituting some carbs for protein. It’s amazing what this small change can do!

For more information on protein and diet, don’t hesitate to contact me!

DW

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Macronutrient 411: Are You “on” Protein?

27 01 2013

Our diets are composed of 3 macronutrients: carbohydrates, fat and protein. I’m going to write a separate article on each explaining why certain macronutrients are preferable to others, which types of macronutrients should be ingested at which times, and other useful tidbits along the way.

Sidebar: I have to comment about the title of this post. It absolutely cracks me up when people ask me if I’m “on” protein. I honestly haven’t been asked this in a while, but when I started lifting weights back in university, I got asked this on a weekly basis. People threw around the question like it made perfect sense, as if whey protein powder was a kind of anabolic steroid. I would seriously hope that we are all “on” protein, much like we should all be “on” fat and “on” carbohydrates. If you aren’t, you’re probably reading this from the hospital. But I digress. Without further adieu…

Protein fast facts

1 g of protein provides 4 kcals of energy.

Dietary protein is absolutely necessary. Without a diet rich in essential amino acids, the human body will cease to function.

There are 12 non-essential amino acids (the human body has the ability to make these) and 8 essential amino acids, those that we must get from our diets. These include isoleucine, leucine, and valine (the BCAAs) as well as lysine, methionine, phenylalanine, threonine, and tryptophan.

Animal proteins are the highest quality proteins. Plant proteins are of a lower quality.

Higher levels of protein in the diet promote satiety (feeling full) and help to maintain a healthy body composition and immune function.

Proteins are critical for nearly every metabolic activity, including:

–  Production of energy (eg, the amino acid glutamine is a primary source of energy in intestinal cells).

– Production of glucose, ketone bodies, cholesterol, and fatty acids

– Synthesis of hormones, enzymes, antibodies, hemoglobin, neurotransmitters, etc.

– Liver protein synthesis

– Muscle protein synthesis

Types of protein

Protein is composed of amino acids. When amino acids join together, they form peptides. These peptides then link to form many different protein structures. Since dietary protein comes from plants and animals, it is already bound in these complex structures and the human body must break it down into individual amino acid groupings for use.  This is why we evaluate protein quality based on amino acid content. With adequate amino acids and energy in the diet, all the necessary proteins for optimal human physiological function can be formed later.

Like carbohydrates, different types of protein are absorbed into the blood stream at different rates. Slower digesting proteins release amino acids more slowly (meat, dairy, casein, etc.) while faster digesting proteins release amino acids more rapidly (whey protein, eggs, BCAAs, etc.). Slower digesting proteins therefore behave more like low GI carbohydrates while fasting digesting proteins behave more like high GI carbs.

Note: Going back to my article on Skipping Breakfast, this is why I also do not recommend eating whey protein/BCAAs/eggs upon waking, as when individually consumed they can cause a spike in insulin, shutting off the fat-burning process of the body. However, like with carbs, consuming fat and/or fiber in the meal will limit this insulin spike, as will choosing to consume slower digesting protein instead of sources that are rapidly absorbed into the blood stream.

BCAAs (branched chain amino acids) are absorbed faster than smaller amino acids. This is why they have recently become a very popular supplement for people that work out, because they enter the bloodstream quicker than any other type of dietary protein, which is what you want when you are working out (prevent muscle wasting, enhance muscle synthesis). It is important to note though, that high dietary intake of BCAAs can cause protein “congestion”, delaying the entry of individual amino acids into the bloodstream.

What does this all mean?

I covered a lot of this in my previous post, Why almost everyone should be on a protein supplement, but let me recap the important parts:

– Getting adequate protein from our diets is not simply important for guys that lift weights- protein is the macronutrient that keeps us all functioning on a daily basis.

– Without adequate protein in the diet, things like enzymes and structural proteins are cannibalized, and vital human functions begin to fail.

– Not all protein is created equal. The Food and Agricultural Organization/World Health Organization (FAO/WHO) uses the measurement of Protein Digestibility Corrected Amino Acid Score (PDCAAS) to determine protein quality in the food we eat. Take a look at the chart below:

prot

Although they rank lower on the scale, vegetable proteins can still provide all the essential amino acids needed by the human body. For those following a plant-based diet, it is therefore paramount to eat a varied intake of foods. Please note however, eating a plant-based diet puts you behind the 8-ball if your goals are to build muscle and maintain a lean body composition. Not only are plant-based proteins less bio-available, but they’re almost universally higher in either carbohydrate or fat than they are protein, meaning you have to take in a much higher caloric load to achieve the same quality and amount of protein. It is for this reason that I would never suggest such a diet to any of my clients; variety and inclusion of both animal and plant sources is the most logical and efficient path to both health and performance.

When it comes to special dietary restrictions, limiting amino acids is the biggest problem. The essential amino acid found in the smallest quantity of the food consumed is considered to be the limiting amino acid. In plant-based diets, lysine is often the limiting amino acid, as cereals and grains tend to be lysine-poor. Lysine is important for the conversion of fat to energy in the human body, as well as the synthesis of collagen and connective tissues, and also serves as an important regulator of calcium levels- again, as an essential amino acid, it is critical to life. Consuming a diet high in both beans (lysine-rich, tryptophan-poor) and wheat/rice (lysine-poor, tryptophan-rich) resolves this issue. Remember however, such a diet will be very high in carbohydrate and be less conducive to overall health and performance than a well-balanced diet inclusive of both animal and plant products.

How much protein do we need?

The recommended minimum amount of protein for sedentary (inactive) adults is 0.7g per kg of body weight. Please note: this is the minimum amount (to prevent deficiency and vital protein cannibalism) for an inactive person. As I stated above, amino acids are vital to our health and function, so why limit ourselves in any way? Recent research has shown that higher levels of protein in the diet can be vital to immune function (think health), metabolism (think fat-burning), satiety, weight management and overall performance. Due to this, many experts recommend protein levels that meet or exceed 1g per pound of body weight for both men and women. If weight-training or another type of high-intensity exercise is part of your lifestyle, don’t be afraid to consume upwards of 1.5g of protein per pound of body weight. When it comes to protein, more will not be detrimental.

When to eat what

Protein should be consumed at every meal. While it is fairly easy for the human body to maintain proper levels of carbohydrate and fat, it is actually quite difficult for the body to maintain a consistent amino acid pool with proper dietary intervention. Amino acids in the body are constantly being used (again, protein is required for nearly every metabolic function) so without dietary intake, things like enzymes and structural proteins will be cannibalized- again, something we want to avoid- and if this happens for an extended period of time, vital functions will being to shut down.

For example, as mentioned above, glutamine is a primary source of energy in intestinal cells. If we do not consume enough dietary glutamine, the body will break down muscle cells to provide the raw materials for intestinal glutamine needs. As you can imagine, this is undesirable for a number of reasons, again hammering home the point that consuming and adequate amount of high quality protein in the diet is paramount.

As certain types of protein absorb quickly and others slowly, there are ideal times to consume different types of protein. A few examples include:

– Although you all know how I feel about breakfast, if you are afraid of muscle-wasting, it would make sense to eat fast-absorbing protein first thing in the morning (whey protein, eggs, fish). However, if your concern is that you aren’t going to be able to eat again for a few hours, it would make sense to eat slower-digesting protein (meat, cheese, casein protein, etc).

–  During extended workouts (75+ minutes), either whey protein or BCAAs should be consumed to prevent muscle wasting. BCAAs are preferable as they are the fastest absorbing and are less likely to cause issues in the gastrointestinal tract.

– Post-workout it is ideal to consume a fast-digesting protein source (whey).

Long story short:

– Consuming an adequate amount of protein is critical to staying alive.

– There are 8 essential amino acids that must be consumed in the diet.

– Protein should be consumed at every meal, as it is constantly being used within the body and tissues will be cannibalized in the absence of dietary protein.

– Individuals with special dietary restrictions need to pay attention to the limiting amino acids in their diets. Eating a diet with a wide variety of protein sources will ensure that all essential amino acids are consumed.

– It is not advisable to eat a diet completely devoid of animal products.

– Different types of protein absorb into the body at different rates, making certain proteins preferable at specific times.

– Everyone in the general population should strive to consume at least 0.7g of protein per pound of body weight on a daily basis.

– Whole foods are preferable to protein supplementation, as they tend to have a slower absorption rate and are higher in vitamins and minerals. However, a protein supplement is far better than not achieving adequate levels of protein in the diet.

This wraps up the Macronutrient 411 series, detailing the importance of carbohydrates, fat and protein in the diet. If you have any additional questions on protein, or the other two macronutrients, please don’t hesitate to send me a message or to post a comment below.

I am so “on” protein.

DW