It’s no secret that I am a big fan of high-protein diets.
Most of my clients come to me with unique problems, and I give them unique solutions. Yet, there is almost always the commonality of increased protein intake.
Why? High protein intake is great for weight loss and provides several additional benefits.
In today’s study summary, I will discuss some of those benefits by explaining the results of two recent scientific studies related to this topic.
Let’s get started!
Important Terms:
Lean Body Mass (LBM): This is the mass of everything except your body fat. It includes muscle mass, skin, bones, organs, and body water. This is important to dieting because ideal diets will reduce fat mass in the body while minimally reducing lean body mass.
Sarcopenia: Loss of muscle tissue
High Vs Low Protein Diet Study:
The study was called “Higher protein intake during caloric restriction improves diet quality and attenuates loss of lean body mass”
“The purpose of this study was to examine how the change in self-selected protein intake during caloric restriction (CR) alters diet quality and lean body mass (LBM).”
This means the researchers wanted to examine if dieters that chose to eat higher protein also had better diet quality and if their diet caused less reduction in LBM.
What the Researchers Did:
The researchers gave food questionnaires to dieters who were being counseled on weight loss by a registered dietitian. Using the data from those questionnaires, they separated them into two groups: a higher protein group and a lower protein group.
The average protein intake in the high protein group was 79 grams daily while the low protein group consumed on average 58 grams daily.
I believe that even the high protein group would have benefited from more protein, and my clients consume much more than that normally. However, as will be seen below, even that amount of protein showed benefits.
After 6 months of calorie restriction the groups had their body composition measured, and the researchers attempted to assess the diet quality of the different groups.
What They Found:
Both groups lost about the same amount of total weight after the trial (5% of their body mass). This does show that if calories are restricted, people will lose weight.
However, the high protein group lost half as much LBM as the low protein group. This means those in the high protein group maintained more muscle and the other components of LBM while losing more body fat.
This is what many experts refer to as “healthy” weight loss.
Additionally, they found that the high protein group had a better diet quality. My definition of good diet quality may differ from theirs, yet one of the key differences they found was the higher protein group consumed less refined grains and added-sugars.
I wholeheartedly agree that those changes improve diet quality.
They don’t hypothesize as to why the diets improved, but I have an idea: improved satiation from higher protein intake.
It is something I see time and time again in my practice – when someone eats more protein they aren’t as hungry and don’t crave sugary or processed foods.
If you want to see a short but very clear video that goes into slightly more detail about this study, watch this video here.
Now onto the next study!
Vegan Diets and Sarcopenia Study:
This study is called “Vegan Diets for Older Adults? A Perspective On the Potential Impact On Muscle Mass and Strength”
The purpose of this study is to look at the conflicting advice older adults are given to consume an adequate amount of high-quality protein while we are also being advised to eat more plant-based foods. They discuss potential problems with plant-based diets for older adults and explain why it is not feasible.
I am a huge proponent of the importance of muscle mass and strength for all adults, especially older adults. If you want to learn more about the importance of muscle mass and health, check out my recent podcast with Dr. Gabrielle Lyon here where we take a deep dive on this topic.
A quick summary of that podcast: increasing muscle mass is one of the most important things anyone can do to achieve better health and age well. How do you do it? You increase high-quality protein intake and do resistance training.
What the Researchers Did:
This is not an interventional trial, review, or observational trial. The authors are simply discussing the current evidence on Sarcopenia and plant-based diets.
They first discuss why it is important that older adults consume adequate protein. Then they discuss why the protein quality of a vegan diet is inferior to one that includes meat. Finally, they discuss why some proposed solutions for the lower protein intake on a vegan diet are ineffective.
What They Found:
Here I’ll summarize some of the main points the researchers raise.
They first provide evidence that most older adults are not consuming adequate high-quality protein. This trend is likely to lead to sarcopenia in older adults and the accompanying health problems associated with that disorder such as increased risk for falls, heart attacks, heart failure, and premature death.
Once again, I have seen that low muscle mass is a recipe for poor health and aging.
The authors then do a thorough analysis of why the protein quality of a vegan diet is inferior due to poor protein digestibility, low protein density, and inferior amino acid profiles. If you want to see their evidence for those claims read the study here.
The one weakness the authors point out is the gap in knowledge that currently exists in medical literature around vegan diets and sarcopenia. They propose a need for well designed interventional trials but do discuss the few articles that currently exist. Those articles propose that a vegan diet likely provides insufficient protein, doesn’t improve sarcopenia, and may actually contribute to the development sarcopenia.
Thus, taken together this is the picture they paint:
- Sarcopenia is a real issue for older adults and most aren’t consuming enough high-quality protein
- Plant protein is not as high-quality as animal protein
- Vegan diets likely don’t prevent or improve sarcopenia and may worsen it
So, if one wants to continue a vegan or plant-based diet is it possible to consume enough high quality protein?
Taking their discussion and some of my own ideas I see three options that all have problems:
- Eat more vegan foods. The authors discuss how this idea of increased portion size could be studied; however, they admit that eating enough plant foods to get adequate protein would be extremely challenging for adults. Additionally, I see the problem of increased calorie consumption which could lead to weight gain and its accompanying problems.
- Eat high-protein plant foods. One could hypothetically eat mostly high protein plant foods and get enough protein while not eating excessive food, although I still don’t believe this is feasible or possible. I have seen or heard the stories of many people woh have attempted this and ultimately failed. However, even if it is possible, as a dietitian I see this option likely leading to nutrient deficiencies. That is why meat just makes sense. It gives you high quality protein and provides a host of important nutrients for the body!
- Consume plant-based protein powders. If you have seen my work, you know that plants don’t want to be eaten and contain defense chemicals. That is a real concern I have for plant-based protein powders as they concentrate large amounts of those defense chemicals into the powder. Take soy protein for instance. Soybeans contain isoflavones and other chemicals that are harmful, and large amounts of soy protein consumption has been found to be harmful to human health. Additionally, if someone is on a vegan diet for ethical or environmental reasons, they need to understand that the industrial agriculture process used to make those powders causes much more damage to the environment and much more harm to animals than proper animal agriculture. If you want to learn more, check out the evidence in my book Sacred Cow.
None of the above are good solutions.
In summary: sarcopenia is a big issue for adults and getting sufficient protein on a vegan or plant-based diet isn’t feasible or even possible for the majority of people. The best way to stave off sarcopenia and age well is to consume high-quality animal protein.
Conclusion:
High protein diets are great and provide benefits in “healthy” weight loss and improving sarcopenia. The best way to consume adequate protein is to consume at least some high-quality animal protein.
If you want to learn more about the nuts and bolts of high protein diets such as sourcing, meal ideas, and how much protein to consume, the best place to start is my Sustainavore Course. I will walk you through exactly how to apply these principles to live a healthy life and age wonderfully.
Additionally, I am going to provide answers to a question I know some may raise.
Q. Do high-protein diets have risks or cause health problems?
A. Unless you have kidney disease or another health problem that impedes your ability to properly process protein, it is almost impossible to eat too much protein. You will be way too satiated, and the only side effect is you will probably lose cravings, eat better, and get a better body composition. If you want evidence to back up that claim, you can see it all in my book Sacred Cow here.
In conclusion, some think I have some kind of vendetta against vegans.
I don’t. If it was a diet that worked, I would be all for it.
The problem is that in my experience, the majority of people don’t do well completely eliminating animal foods. I believe animal foods are extremely nutrient dense, give high-quality protein, and are essential to a good diet.
I also think that using animal proteins to consume a high protein diet is extremely beneficial for human health.
If you have further questions about the ethical, environmental, and nutritional case for meat, I recommend you either read my book with hundreds of sources backing these claims or take my Sustainavore Course to learn more.
Now go eat some protein!
-Diana
Reference studies:
