Blog Post

Is Protein One of the “Secrets” for Weight Loss?

Chicken Breast being prepared

A few weeks ago, I presented at a small conference on protein for weight-loss as I feel like it is a subject that is undervalued by a lot of dietitians. Since I am a Gary Vee fanboy and love his idea of pillar content, I figured I would also turn aspects of that presentation into this blog post and share it on a larger scale.

My background prior to studying nutrition at university started with an excessive amount of time reading the forums on during 2012, followed by even more procrastination in the form of being an active member of a niche bodybuilding/powerlifting forum from 2013-2014. I feel like this has given me a different perspective to other dietitians who have come from different backgrounds.

There was a lot of “bro-science” on these forums and potentially bias towards high protein diets in general. Filtering through a lot of inaccurate information, I was amazed when I found out there was something of an evidence-based community where there were people who were wayyyyyy smarter than I ever will be when it comes to nutrition. People like Alan Aragon, Layne Norton and Eric Helms are the first ones to come to mind as they are quite well known now, but there was an endless list of intelligent people. The key thing is that all these guys were experts in body composition manipulation.

On these forums, at that time there was no such thing as the HAES movement. The entire sport of bodybuilding involves manipulating your body composition. There was never a question about whether it was possible to lose weight (in this case just focusing on losing body fat and maintaining lean muscle mass) and keep it off. It was just something that was done on a consistent basis.

The thing that piqued my interest and has stayed with me to this day is the fact that the recreational bodybuilders tended to have high-calorie requirements. Their calorie requirements grew year after year as their metabolism got faster since they were consistently gaining more muscle and size. A lot of these people struggled to eat enough calories to maintain their weight and had to force-feed themselves to gain weight.

Of course, extreme dieting involved in contest preparation appears to negatively affect metabolic rates considerably, but the people who weren’t near a competition were often eating a ridiculously high number of calories in comparison to the average person.

Short Term

The reason why this title is such a clickbait title is because we all know that there is no secret to weight-loss. What IS necessary though is a calorie deficit. There are so many ways to achieve this, and they don’t all require a high protein intake. I believe that a higher protein intake will make it easier to stay in a calorie deficit though.

The research is clear that protein is the most satiating of all the macronutrients. If you eat 1500 calories per day and have 30% of your calories coming from protein, you will likely feel fuller than if you had 15% of your calories coming from protein. If you have a higher protein intake, eat plenty of low-calorie vegetables and drink a lot of water, you can physically stuff yourself full before reaching your calorie target for weight-loss.

A calorie deficit over an extended period of time is almost always going to result in some form hunger even if you are physically full, likely due to hormonal changes that are influenced by the number of calories consumed. While this is something that might be difficult to manage, it is clear that eating total food volume will make this process easier to.


Chicken Breast Nutrition

If numbers make you want to zone out, feel free to skip to the next section. I won’t blame you.

A large percentage of people who are overweight would lose weight on 1650 calories per day. I’ve chosen that number because it makes the maths easier for this example, but feel free to adjust it for whatever calorie target you see fit.

– 100g of chicken breast (just over half a breast) is 10% of that number
– 200g of chicken breast is 20% of that number
– 300g of chicken breast is 30% of that number
– 400g of chicken breast is 40% of that number

I’ve gone as high as 400g because very few people would eat as much as 400g of chicken breast. The fact that such a large (and filling) amount is still only 40% of that number for a solid rate of weight-loss (not even weight maintenance) is what I want you to take note of. This example applies to all lean meats, just with slightly different numbers.

Lean cuts of meat can be quite filling for the number of calories they contain. If you choose to cut down on that area but replace it with a source of calories that is not as filling, then it will make creating a calorie deficit more difficult.

Long Term

From a practical perspective, I have found that I need to get clients results in the short-term for them to buy into my system well enough to get great results over the long-term. The long-term stuff is what I really care about though.

Fat-free mass is the biggest factor in our metabolic rate. We can use formulas to predict basal metabolic rate which includes the amount of fat-free mass somebody has and they are often more accurate than most people would expect.

You always hear about people who have a “fast metabolism” or a “slow metabolism” but major outliers are rarer than you would think. One of my favourite studies on this topic highlights that people who believed they were diet-resistant and reported calorie intakes of ~1200kcal per day were underreporting by an average of 47% when their intake was tracked accurately. Out of the 224 subjects, all BMR’s were within 10% of what a formula predicted it would be. So many aspects of this were mind-blowing to me when I first read it. It does, however, add another highlight as to why we should be cautious in our interpretation of personal anecdotes regarding calorie intake.

On average when people diet while eating the NRV for protein (0.84g/kg), ~50% of the weight-loss comes from muscle if their activity is unchanged. If they regain weight, only 1/3 comes back as muscle. I originally saw research indicating this in Alan Aragon’s Monthly Research Review, but haven’t been able to find it since (due to their being 1000s of studies in there and me not being able to recall the specific issue I saw it in).

Regardless, there is no doubt that eating at 2x the NRV or 3x the NRV for protein results in far better preservation of muscle mass during weight-loss. Since muscle is the biggest factor in our metabolic rate, it makes sense that keeping as much muscle as possible during weight loss should be a priority. If somebody maintained most of their muscle during weight loss and happened to regain weight later, they would likely have more muscle then where they started and be in a better position metabolically to lose weight in the future.

I don’t want to overstate the impact gaining muscle has on our total daily energy expenditure though. It appears as though 1kg of muscle results in roughly 12kcal burned per day. Fat burns roughly 4kcal per kg. Other organs burn more calories per kilogram, but because muscle makes up a larger portion of the total body’s mass in comparison to organs, that is why it makes up the largest portion of a somebody’s BMR. When you put it into context though, gaining 10kg of lean mass still only results in an extra ~100-120kcal/day being expended. Gaining 10kg of muscle is a slow (and potentially unrealistic) process, which still doesn’t result in outstanding returns in terms of BMR.

At the other end of the spectrum, I am not comfortable helping somebody lose weight if the proposed method is likely to result in a large percentage of their weight-loss coming from muscle.

I believe this is a small factor in why a lot of people yo-yo diet. They lose a lot of muscle as they lose weight, and then don’t regain as much when they regain the weight. Each time they diet in that fashion either their metabolism gets slightly slower, or they end up at a higher weight with the original amount of muscle mass and total daily energy expenditure that is too low for their habitual calorie intake. I believe protein intake is a large piece of the puzzle for solving that. I also believe that resistance training would go a long way to solving this issue too.

One aspect we have less control over is the metabolic adaptation to dieting. This is a is the concept of where the body’s energy expenditure drops to a greater extent than what you would predict with a formula while dieting, or alternatively energy expenditure increases more than a formula would predict based of weight and activity while in a calorie surplus. It is part of the body’s way of manipulating its role in energy conservation. If you have more calories available, you burn a little bit more. If you have less available, you burn less, and your body prioritises its highest needs first. My other blog post goes into detail in regards to how this occurs, but the image below is an example of what this could look like for somebody losing weight, where TDEE is total daily energy expenditure.

Metabolic Adaptation

How Much Protein

The amount of protein really depends on the individual. The main thing it depends on is how lean somebody already is because the needs are based on metabolically active tissue. For people who are already relatively lean (e.g. athletes) and performing resistance training with the goal of optimising muscle mass, the target should be between 1.6-2.2g/kg of bodyweight. This is so well studied that it is not up for debate. Some special snowflakes might perform better at a higher target or lower target, but these are extreme outliers.

For people who are ridiculously lean (e.g. competitive bodybuilders prepping for a show), the target goes up to 2.3-3.1g/kg of fat-free mass.

In most cases, regular people looking to lose weight will be at a higher body fat percentage. For these people, the target would be lower. I tend to use clinical judgement on this since there are multiple factors beyond just body composition, but a good guide for optimising body composition is ~1.8-2.6g/kg of fat-free mass.

Ideally, the protein should be spread out evenly across the day. This could create slightly better results although it appears to matter more in a calorie surplus than in a deficit. Don’t be fooled into believing that “the body can only absorb 20-25g of protein in a single sitting” since the research is clear that you can absorb way more than that, and what really matters is your total intake. In a perfect world, if somebody was having 100g protein per day, it would be split between 4 meals of 25g of protein. This is not always practical for everybody though.

Kidney Function

High protein diets do NOT cause issues with kidney function unless people already have issues. This is one of the most common myths out there. It is so commonly accepted among health professionals that a lot have never actually looked at the evidence and found out that there is no need for concern.

For those who DO have issues with kidney function, it is best to refer to the evidence-based practice guidelines for the nutritional management of chronic kidney disease. For stage 3 chronic kidney disease the guidelines recommend 0.75-1g/kg IBW protein. From experience seeing a lot of clients with CKD over the last two years, I believe far more people are going to be under that target rather than over. Protein-energy malnutrition increases with deteriorating kidney function and is associated with adverse outcomes.

Practical Strategies

The first step involves changing people’s mindset around protein. A lot of people have been told their whole lives to limit to a palm-sized portion of meat. While there are plenty of other ways to get protein, my experience has been that it is difficult to get people to consume ~1.4g/kg of protein mostly from non-animal sources, while also being in a calorie deficit, unless they are quite motivated. My general approach is counter-intuitive, but it often involves increasing the intake of lean meat (while also limiting higher fat meats).

Usually, the first thing I push for is ensuring there are at least two decent servings of protein throughout the day. Generally, this will be at lunch and dinner since most people enjoy lower protein breakfasts. Often lunch will still have a smaller portion of protein than dinner since people habitually have larger dinners than lunches.

The next step I will take is adding in higher protein snacks. My go-to that people most commonly implement is adding in a higher protein nut bar (e.g. Carman’s Gourmet Protein Bar, Tasti Protein Bar or Hillcrest Protein Bar) and adding in a higher protein yoghurt which is low fat and low/no added sugar (e.g. Chobani, Ski Soliel, Yoplait Forme’ or YoPro). This will add in 20-25g of protein just coming from snacks that most people are going to enjoy anyway. Most of the time I would opt for flavoured yoghurts rather than natural flavoured ones, to help improve compliance/enjoyment over the longer term.

Take-Home Messages

Meeting your protein targets (which could be higher than some will lead you to believe) will make it easier to stay in a calorie deficit over the short term and the long term. Over a smaller timeframe, it helps by making it easier to manage your appetite. On a larger scale, it will help keep your metabolic rate higher, slightly increase the thermic effect of food and also continue to manage appetite, which could make it easier to create a calorie deficit.

By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been interested in all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.