Why Your Body Stops Responding to Protein

For a variety of reasons, more people than ever have become aware of just how valuable protein is to the process of muscle building, along with protein’s massive contribution to body recomposition efforts. Millions of people have completely remade their bodies and changed their life circumstances for the better by increasing their protein intake.

Regrettably, there are several reasons why your body may stop responding to protein, at least in the ways it initially did when you began increasing your protein intake, either through meals, supplements, or both. 

If this describes your situation, don’t fret. There are certainly one or more diagnosable reasons why your body has stopped responding to protein the way it used to. Even better,  there’s certainly a strategy you can follow to solve the problem.

1. Increased anabolic resistance

There are a number of factors that can cause your body to increase its anabolic resistance over time, which is another way of saying that your muscles have become less sensitive to factors that contribute to increases in muscle size, including both the presence of protein, and resistance training itself.

Common contributors to an increase in anabolic resistance are periods of inactivity, serious illnesses, high inflammation, and obesity brought about by inactivity. The majority of these reasons can be overcome by a return to consistent resistance training.

The aforementioned reasons notwithstanding, the primary reason for increased anabolic resistance is aging. As a general principle, older adults are encouraged to boost their protein intake to the maximum recommended level of 1.6-2.2 g/kg in order to preserve their muscle mass, and especially if they are actively training.

2. Diminishing returns and full muscles

Ongoing studies of protein’s performance within human anatomy have led to the general conclusion that total protein intake throughout the day is far more important to maximizing muscle hypertrophy than consuming protein within specific windows of time.

This is true, but it is still helpful to be aware of how your body responds to the presence of protein. Specifically, when you consume a large amount of protein, this elevates muscle protein synthesis within your body for a period lasting approximately four hours. This results in the “muscle full” effect, during which there are diminishing returns on additional protein ingested during this time.

To be perfectly clear, the additional protein consumed during this period of time is not wasted, but its muscle-boosting potential is not quite as potent as it could otherwise have been. This is one of the reasons why it is frequently encouraged for meals to be consumed every four to five hours, with protein contributing abundantly to each meal’s content to ensure that muscle protein synthesis remains both high, and consistent.

3. Your original protein doses are no longer adequate

If you began your protein supplementation at a point when your overall protein intake was rather low, your body’s response to that protein was probably swift and pronounced. Once your muscles finally had access to the protein they had been craving, they adapted accordingly by rebuilding themselves in a larger, stronger configuration.

For the sake of argument, let’s say that the addition of 20 grams of supplemental protein boosted your total protein intake to 80 daily grams from 60 grams. Certainly, elevating your protein intake by 33% generated a favorable response, but to put it in simple terms, your body may have maxed out the gains it can provide you with when you’re consistently consuming well under 100 grams of protein today. This is especially true if your body weight suggests that your muscles would respond best to protein in quantities of 150 grams per day or more.

In order to accommodate a body that has maximized the muscle mass it can craft on protein quantities that are well below what it needs to optimize muscle growth, you are advised to prioritize protein intake throughout the day, and consistently consume more protein than you do presently.

4. Low leucine levels in your protein

One of the most uncomfortable conversations to have with someone who is conscientious about what they eat is often about the insufficiency of their preferred protein. This is routinely the case when it comes to vegan or vegetarian protein options, because pointing out slight nutrient insufficiencies in plant-based protein sources in comparison to animal sources is often construed as criticizing a lifestyle, when this doesn’t necessarily need to be the case. 

For the sake of clarification, plant-based protein sources are often low in key amino acids when it comes to their density, and only in a relative sense. As a case in point, the amino acid leucine, which is essential to maximally trigger muscle protein synthesis, is generally lower in plant sources like peas and soy than it is in an animal source like whey.

If the potency of the muscle protein synthesis in your body is falling short because of a shortfall of leucine, and if you’re already taking a plant-based protein supplement like pea protein, the answer may be as simple as increasing your dose of pea protein from 25 grams to 40 grams per serving. This will ensure that you’re receiving the same level of leucine that you would acquire from a 25 gram dose of whey protein.

5. Your caloric intake it too low

It is absolutely possible to increase our muscle mass while your body is in a caloric deficit, but that doesn’t make it easy, and it’s certainly not viable as a sustainable long-term strategy for muscle growth. This is an important fact to process, especially if you subscribe to the common bodybuilding approach of bulking to maximize muscle mass, and then cutting to improve your vascularity and lean muscle visibility.

For example, if you suddenly shift from your normal caloric intake and an aggressive resistance-training routine to a restricted-calorie diet and lots of calorie-burning cardio, your body will quickly shift to breaking down muscle for calories along with the fat you’re shedding. Granted, you may end up with the body composition you’re ultimately looking for, but at the cost of some muscle mass that you’ll ultimately wish you were still carrying with you.

If you’re committing to a reduced-calorie diet and a higher volume of training activities that rapidly burn calories, you are strongly advised to increase your protein intake to the maximum advised level of 2.2 g/kg — or 1.0 gram per pound of body weight — to preserve your existing muscle mass, and possibly continue to promote new muscle gains.

6. Insufficient training stimulus

Experienced lifters who have maxed out their protein intake and optimized their workouts will certainly notice when they are achieving diminishing returns on their strength training. This is an inevitable outcome of progressing toward your genetic potential, and approaching the maximum amount of muscle mass that your body can naturally carry.

While this is common — and ultimately likely if your nutrition plan and training regimen remain dialed in for long enough — you should evaluate your workout to determine whether or not you have sufficiently advanced the challenge and difficulty of your training in a way that would produce new changes. 

If you’re not training hard enough, no amount of protein intake will compensate for hard work that isn’t being performed. With this in mind, please make sure that you are still adhering to the principles of progressive overload as your body gets stronger so that the protein you’re consuming can help your body make the necessary adaptations to meet those rising challenges.

Revive your mass-building mechanisms

There are plenty of reasons why your body may not be responding to protein the way it used to, and the problems may lie with your training, your timing, your age, your lifestyle, or your preferred form of protein itself. 

Nevertheless, all of these factors are capable of being overcome if you adopt the right approach. So above all else, remain positive, apply the remedies prescribed above, and get back to striving to achieve your personal peak in muscle potential. 

Summary

1. There are several reasons why your body may become less responsive to the presence of protein in your body.

2. Age, inactivity, and obesity may make your body less sensitive to protein and to training in general.

3. Failing to space out your protein intake can prevent your body from capitalizing on its muscle protein stimulus potential throughout the day.

4. Plant-based proteins often need to be consumed in higher quantities than other protein sources to accommodate for shortfalls of crucial muscle-building amino acids like leucine.

5. Following a reduced-calorie diet without increasing your protein content can make it virtually impossible to build new muscle mass.

6. If your workout is no longer as challenging as it used to be, your body may not be incurring the training stimulus necessary to initiate new muscle growth.