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

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 bodybuilding.com 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 lot of “bro-science” on these forums and potentially a 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 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 peaked 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. Most of these people struggled to eat enough calories to maintain their weight and had to force feed themselves to gain weight. The extreme dieting involved in contest preparation appears to negatively affect metabolic rates considerably, but the people who weren’t competing 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.


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.

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.

Muscle is the biggest factor in our metabolic rate. We can use formulas to predict metabolic rate based on 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 reporting 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.

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 studies showing this in Alan Aragon’s Monthly Research Review, but have recently cancelled my subscription (after spending >100 hours’ reading through all of content up until this month) so I no longer have access to it.

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.

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 track the muscle mass of my clients as they progress, and I haven’t run into this issue, but if somebody was losing 50% of their weight from lean tissue (and they weren’t already exceptionally lean), then I would question whether it is ethical to continue down that route.

I believe this is a massive reason 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 weight. Each time they diet in that fashion either their metabolism gets slower, or they end up at a higher weight with the original amount of muscle mass and a metabolic rate which is too slow 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. Lyle Macdonald explains this perfectly in one of his blog posts. “Let’s say that someone loses twenty pounds and based on all of the math you’d expect a drop in metabolic rate of 10%. But when you measure it you actually see a reduction in 15%.” This drop in metabolic rate is slightly larger than what would be predicted by a formula. This is called metabolic adaptation. It’s not fully understood, but it is likely related to hormonal changes. The best explanation is that it is related to a drop in leptin, thyroid levels, sympathetic nervous system activity and a few other things along those lines that are needlessly complex to discuss. There are a few methods that can be used to help offset this, such as planned diet breaks, but that is beyond the focus of this post.

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. ~1.4g/kg of body weight is a solid target for most of the people I see, but the higher a person’s body fat percentage the lower the number would be since it is based on metabolically active tissue. I tend to use clinical judgement on this since a lot of the research is based on bodyweight rather than fat-free mass, but a good guide is ~2.2g/kg of fat free mass.

Ideally spread the protein out evenly across the day. This has been shown to create slightly better results. Don’t be fooled into believe 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, I have found that it is very difficult to get people to consume ~1.4g/kg of protein mostly from non-animal sources, while also being in a calorie deficit. My general approach is counter-intuitive, but it really 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 go to 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 requirements (which are often 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, which will make it easier to create a calorie deficit.

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