bite my words

Dispelling nutrition myths, ranting, and occasionally, raving


Thoughts on “The Myth of High-Protein Diets”


Image used under a Creative Commons Licence. Photo by Sean_Hickin on flickr.

Part of me is a little hesitant to address the op-ed piece by Dr Dean Ornish in the New York Times last week. This because, the low-fat zealots have already attacked me for criticizing Dr Esselstyn in the past. But, you know me, when something gets under my skin I can’t leave it well enough along.

The piece was titled: The Myth of High-Protein Diets. One would think that the accompanying article would be about pitfalls to following a high-protein diet. However, Dr Ornish focusses solely on animal protein, with an emphasis on meat and fat. The gist of his argument is that if you eschew animal products you will live longer, as will the planet. Okay, so it’s not the myth of high-protein diets. It’s the myth of high-animal products diets.

One of the studies Ornish cites is one that I blogged about a year ago. At the time it ignited headlines proclaiming that protein was akin to smoking and that animal protein would contribute to our premature demise. Suffice to say, the study was flawed and these conclusions were tenuously drawn. In fact, in older adults, diets that were higher in protein were actually positively correlated with reduced mortality. And there was no negative effect from plant sources of protein at any age. So, even with the poor quality of this research, some of the results were in direct opposition to Ornish’s interpretation of them.

I read articles like this and think to myself “it’s no wonder that people are confused about what to eat and don’t trust any health care professionals”. You have one doctor insisting that a low-carb diet is the key to a long healthy life, another insisting that it’s low-fat, another insisting that it’s high-carb, another insisting that it’s blahblahblah. Of course, they all have the book to sell you. Maybe they’re all right. Maybe you can be healthy one any of their highly-restrictive diets. As I’ve said before, the best diet is the one that you can enjoy and follow for life. For me, that involves eating fat, protein, and carbs from both plant and animal sources. Yeah, I know it’s not sexy, but balance and variety are the hallmarks of a nutritious diet.


Are we all really getting too much protein?


This story is one of the oldest ones. When I was study nutrition in university I remember learning that most of us eat more protein than we need. While it’s undoubtedly true in most cases. It’s a little bit more complicated than: we eat more protein than we need to, end of story.

It’s important to note that there are a number of times that protein requirements are increased, such as for athletes, those recovering from injuries, and those endeavouring to lose weight. However, the recommendation for adults is roughly 45-50 grams of protein per day; more precisely, 0.9 grams per pound of body weight. We can easily eat this in one meal. And the problem is that many of us do eat this in one meal, neglecting the rest of our meals.

New research is indicating that we can’t utilize anymore than 20 grams of protein at one sitting. This means that, while we may be consuming plenty of protein at supper time, we may still not be getting enough protein. Many of us neglect breakfast. Even if we consume breakfast it’s often toast or cereal and many of us don’t get any more than 7 grams of protein in the morning. Distribution is important. To optimize protein utilization we should aim to consume 15-20 grams of protein at each meal. This may mean rethinking breakfast, and supper for that matter. Try to incorporate protein-rich foods at breakfast (e.g. eggs, beans, nuts, seeds, Greek yoghurt) and try to eat more meatless meals for supper. When having meat for supper don’t make it the biggest item on your plate. Treat meat like an accoutrement and make vegetables the stars of your suppers.


More on protein

I don’t know if it’s just me, but I have been seeing a bunch of infographics such as these lately:


While the second one’s much better than the first (credit: Avery Muether Illustrations), it includes fairly accurate protein quantities (and some of these foods are reasonably high sources of protein), I still wanted to comment on them. I went through the foods included in the first infographic and looked up the protein in a serving of each. Here they are:

spirulina (1 tbsp dried) – 4g

goji berries (2 oz dried) – 8g

chia seeds (1 oz) – 4.4g

spinach (1 cup raw) – 0.9g

hemp seeds (2 tbsp) – 10g

barley grass (6g dried) – 1.5g

brazil nuts (1 oz) – 4g

broccoli (1 cup raw) – 3g

(bean) sprouts (1 oz) – 0.8g

figs (1 oz dried) – 0.9g

avocado (1 oz) – 3g

maca (1 tbsp powder) – 1g

kale (1 cup raw) – 2g

romaine lettuce (1 cup shredded) – 0.6g

For the most part, I wasn’t overwhelmed by the amount of protein in these foods. Considering that a single serving of protein is considered to be approximately 6-7g. Even if you consumed all of these foods in a day you would be consuming only 44.1g of protein in total. This is quite close to the needs for many women. Protein needs are generally 0.8g per kg of body weight. However, more protein may be needed in some cases such as for athletes, pregnancy, wound healing, childhood, elderly, etc. Even so, most of us handily exceed the daily requirements for protein.

There is something else beyond total protein to consider, however. We also need to look at protein quality. High quality proteins are those that contain ample amounts of all nine essential amino acids. I’m sure you already know this but just as a refresher… Amino acids are the building blocks of proteins. There are 20 (or 21 if you count cystine) amino acids, 9 of which are considered essential because our bodies cannot synthesize them and must, therefore, obtain them from food. Animal proteins (with the exception of gelatin) are considered to be high-quality as they contain all of the essential amino acids in ample quantities. Many plant proteins are considered to be low-quality as they are either low in, or lack, one or more of the essential amino acids. While it’s absolutely possible to obtain all of the amino acids we need from plant proteins it also takes more careful consideration than proteins obtained from animal sources. This is why we talk about complementary proteins. These are plant protein sources that, when combined, yield adequate amounts of all 9 amino acids. A few examples are: hummus and pita, rice and beans, veggies and polenta. Just to be clear, the complementary proteins needn’t be consumed together at the same meal (although they certainly can be) as long as they’re consumed throughout the day.

Generally speaking, aside from foods such as beans, nuts, and seeds, plant proteins are lower in total protein (not just essential amino acids) than animal proteins. Just a few examples: 3 oz of canned tuna has 21.6g of protein, 3 oz of chicken breast has 21.3 g, Greek yoghurt can contain up to 15-18g per serving.

Yes, it is possible to consume adequate protein without consuming animal products. It’s likely preferable if we do favour plant sources of protein over animal sources. However, it’s not as simple as those infographics make it seem. Most foods contain some quantity of protein. That second infographic especially irks me. Suggesting that romaine lettuce and figs are good sources of protein is ludicrous.

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Forget sugar. Protein is the new smoking.


A recent study in Cell Metabolism prompted numerous headlines proclaiming that protein (specifically animal protein) may be just as bad as smoking for your health. Before we jump on the anti-protein bandwagon let’s take a look at the actual study.

The researchers used the results from the NHANES (National Health and Nutrition Examination Survey) in combination with mouse and cellular studies. There were over 6, 000 participants in the NHANES which is quite a robust sample. Right off the bat it makes me suspicious that the researchers would also need to incorporate mouse studies. We also know that using nutrition data from self-reported surveys is far from ideal: people tend to under-report food intake. In this case the researchers used 24-hour recall. The pro to this is that it’s one of the more accurate methods for collecting dietary data. The major con to this is that the researchers are assuming that food/nutrient intake from one day is representative of intake every day. That’s a huge assumption. I know that I might eat animal protein at a couple of meals on one day while eating none on another. That would mean I could fall into either the low or high protein intake group depending on the day data collection was undertaken. We also know that mice are not humans (duh) and that research conducted using mice may not be translatable to a human population. Okay, not enthusiastic about the methods, but let’s take a look at the results.

The researchers found no association between all cause, cardiovascular disease, nor cancer mortality and protein intake in all participants over the age of 50. They did find an increase in mortality in participants in the high protein (20% or more of total daily calories from protein) group who had diabetes. Naturally, they could not say with certainty if the high protein intake was the cause of diabetes mortality. However, when they broke the results down further (splitting the group into those aged 50-65 and 66 and up), they found a relationship between high protein intake and all-cause and cancer mortality in the 50-65 age group. They reached the conclusion that animal-based proteins were the cause of this increased mortality because when they controlled for animal protein the “association between total protein and all-cause or cancer mortality was eliminated or significantly reduced”. This was not seen when plant-based protein was controlled for. Interestingly, the opposite was found in the over 66 years age group (i.e. higher protein intakes reduced risk of mortality from cancer or cardiovascular disease).

It appears that the researchers didn’t control for all confounding variables when they were examining mortality and protein intake. There is no mention of controlling for physical fitness, economic status, or employment status. These are important factors to consider when investigating the effect of diet on mortality.

So, what can we conclude from this study? High animal protein intake may increase your risk of mortality if you’re between the ages of 50-65. After that, it may have a protective effect. This suggests that protein plays different roles at different ages and also means that we cannot extrapolate the results to those under the age of 50. We also can’t be certain that the results are accurate due to the limits when using dietary recall data as well as the lack of control for certain potential confounding variables. There may be some benefits to including more plant-based sources of protein in our diets; however, it may be premature for us all to go vegan.

After writing this post, I read the review of this study on in which they address the mouse study. They also make some really good points about the protein-human study, including the fact that there’s no differentiation between protein sources beyond separating animal and plant proteins (can we really assume roast chicken is the same as beef jerky?). I highly recommend taking a look at their review.


Grocery Store Lessons: Protein powder


As with all foods/supplements, all protein powders are not created equal. Protein powder isn’t something that I consume much of. I find it’s often gritty and overly sweet and I’m confident that I can get adequate protein from consuming whole foods. However, for the sake of product knowledge, I do occasionally try a protein shake as part of my breakfast.

I always look at the protein content of each protein powder. As an aside, most tend to be about 24 grams per serving, although, some, such as hemp protein powder, can be considerably lower (8-15 g). Something I never considered looking at was the sodium content until one day I just happened to notice it on the package shown on the above left. I was shocked that a serving of protein powder would contain half a day’s worth of sodium. It is a “sport” protein so maybe that’s why; to replace electrolytes lost during an exceptionally sweaty workout. Still, I’m sure that most people wouldn’t expect to be getting so much sodium from a protein shake and I imagine that there are others out there like me who never even thought about looking at this information. I started looking at the nutrition information labels on other protein powders in the store. Most were similar to the much more reasonable 130 grams seen in the whey protein powder (pictured above right).

If you do consume protein powder regularly you might want to check the label to ensure that you’re not getting more sodium than you bargained for.