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Protein – Everything personal trainers need to know for their clients.

Protein – Everything personal trainers need to know for their clients.

You probably know how important protein is for your own fitness goals. 

But are you confident in advising your clients on the right protein intake for their individual goals? 

Many trainers miss critical nuances that can make a significant difference in muscle growth, recovery, and overall performance for the people they work with.  

But understanding the intricate details of protein consumption is crucial. 

This article lays out everything you need to know. 

How much protein does your client really need?  

How does this change depending on their goal or the kind of training they’re doing?  

What are the best sources of protein for them?  

And what are the key times of day they should be consuming them?  

By mastering these aspects, you’ll enhance your ability to guide your clients toward better results that will set you apart... 

Understanding Protein and Its Role 

What is Protein? 

It’s worth spending two minutes refreshing your mind on the basic science of protein that you’ll need to know as a personal trainers. 

Protein is one of the three macronutrients essential for human health, alongside carbohydrates and fats. It’s a fundamental building block of muscle, skin, hair, and virtually every other body part or tissue.  

Proteins are composed of smaller units called amino acids, which you’ve probably heard` referred to as the "building blocks" of protein. 

Amino acids are vital for many bodily functions, from creating enzymes and hormones to supporting immune function. There are 20 different amino acids, nine of which are considered essential because the body cannot produce them on its own. These essential amino acids must be obtained through the diet. Understanding the role of these amino acids is crucial for any personal trainer, as they directly influence your clients' muscle growth and recovery processes.  

What’s the Importance of Protein in Fitness?

Muscle Protein Synthesis (MPS) 

When you’re doing resistance training, your muscles undergo stress and minor damage. To repair this damage and grow stronger, the body relies on muscle protein synthesis. Protein intake stimulates MPS, providing the necessary materials for muscle repair and growth. This is why protein is so heavily emphasised in fitness and bodybuilding communities.  

Recovery and Muscle Repair 

Post-exercise, your clients’ muscles need protein to recover and repair the microtears that occur during workouts. Consuming adequate protein ensures that these repairs are done efficiently, reducing recovery time and enhancing performance. Fast-digesting proteins like whey are particularly effective post-workout because they provide a quick influx of amino acids to the muscles. 

How Much Protein Do You Need? 

General Protein Guidelines 

Recommended Daily Allowance (RDA) 

The Recommended Daily Allowance (RDA) for protein intake for a healthy adult is 0.8 grams per kilogram of body weight. This equates to about 0.36 grams per pound. For example, a person weighing 70 kg (154 lbs) would need approximately 56 grams of protein per day. However, this recommendation is for the general population and is often insufficient for those engaging in regular physical activity, particularly resistance and endurance training. 

Adjusting for Active Individuals vs. Sedentary Individuals 

For clients who are more active, especially those involved in regular endurance or strength training, their protein needs are significantly higher. Active individuals require more protein to repair and build muscle tissues, support energy metabolism, and improve overall performance and recovery. As a personal trainer, it’s crucial to tailor protein recommendations based on your clients’ activity levels to ensure they meet their fitness goals effectively. 

Protein Needs for Different Types of Training 

Endurance Training Protein Requirements  

Endurance athletes, such as runners, cyclists, and swimmers, require a higher protein intake to support muscle repair and recovery due to the prolonged nature of their training sessions. The general recommendation for endurance-trained individuals is between 1.2 to 1.4 grams of protein per kilogram of body weight (0.55 to 0.64 grams per pound). For instance, a 70 kg endurance athlete should aim for 84 to 98 grams of protein per day. 

Strength Training Protein Requirements 

Strength athletes, including bodybuilders, powerlifters, and those focused on resistance training, need even more protein to support muscle hypertrophy and repair. The recommended intake for strength-trained individuals is between 1.6 to 2.0 grams of protein per kilogram of body weight (0.73 to 0.91 grams per pound). Thus, a 90 kg strength athlete would require between 144 and 180 grams of protein daily to optimise muscle growth and recovery. 

Calculating Protein Needs Based on Body Weight 

To determine the precise protein needs for your clients, use their body weight as a baseline. For example: 

  • A 60 kg (132 lbs) endurance athlete should consume between 72 and 84 grams of protein daily (60 kg x 1.2 and 1.4).
  •  An 80 kg (176 lbs) strength athlete should aim for 128 to 160 grams of protein daily (80 kg x 1.6 and 2.0).  

By calculating protein needs based on body weight and type of training, you can provide personalised and effective nutrition advice. Understanding these protein guidelines and how they vary with different types of training is essential for any personal trainer. It ensures that you can give precise, evidence-based advice, helping your clients maximise their results and demonstrating your expertise in the field. 

Timing of Protein Intake 

Pre-Workout Protein 

Benefits of Consuming Protein Before Exercise 

Consuming protein before a workout can provide several benefits. Pre-workout protein helps prime the muscles for exercise, ensuring they have a steady supply of amino acids during the training session. This can lead to increased muscle protein synthesis (MPS) during and immediately after the workout, enhancing muscle growth and repair. Additionally, protein consumption before exercise can help stabilise blood sugar levels, providing sustained energy and preventing mid-workout fatigue. 

Recommended Amounts and Timing 

For optimal results, it is recommended to consume around 20 to 25 grams of protein about 30 to 60 minutes before exercising. This amount can vary depending on individual needs and the type of protein consumed. Fast-digesting proteins, such as whey, are ideal for pre-workout consumption as they quickly deliver amino acids to the muscles. If your client prefers whole foods, options like a small chicken breast or Greek yoghurt can also be effective. 

Post-Workout Protein 

The Anabolic Window: Myth or Reality? 

The concept of the anabolic window suggests that there is a short period post-exercise during which protein consumption can significantly enhance muscle repair and growth. While some studies support the existence of this window, suggesting that protein should be consumed within 30 to 60 minutes post-workout, more recent research indicates that the window may not be as narrow as once thought. Muscle protein synthesis remains elevated for several hours post-exercise, allowing for a broader timeframe for protein intake. 

Optimal Timing for Protein Consumption Post-Exercise  

Despite the debate on the exact timing, it is generally agreed that consuming protein shortly after a workout is beneficial. Aim for your clients to consume 20 to 30 grams of protein within two hours of completing their exercise. This helps kickstart the recovery process and provides the necessary nutrients for muscle repair. Fast-digesting proteins like whey are ideal immediately after a workout, while a combination of fast and slow proteins can be beneficial if your client won't have another meal for several hours. 

Daily Protein Distribution 

Importance of Spreading Protein Intake Throughout the Day 

Consistently distributing protein intake throughout the day is crucial for maintaining a positive nitrogen balance and supporting continuous muscle protein synthesis. Instead of consuming large amounts of protein in one or two meals, spreading intake across multiple meals and snacks ensures a steady supply of amino acids, optimising muscle repair and growth. 

Strategies for Multiple Feedings 

To maximise the benefits of protein, encourage your clients to aim for four to six smaller meals or snacks containing protein each day.  

Here are some practical strategies: 

  • Breakfast: Include protein-rich foods like eggs, Greek yoghurt, or a protein shake. 
  • Mid-Morning Snack: Opt for a handful of nuts, a protein bar, or cottage cheese. 
  • Lunch: Incorporate lean meats, fish, or tofu in salads or sandwiches. 
  • Afternoon Snack: Consider a smoothie with protein powder, fruit, and vegetables. 
  • Dinner: Focus on protein sources like chicken, turkey, or legumes. 
  • Evening Snack: A serving of casein protein or a small portion of cheese can provide slow-digesting protein overnight. 

Best Protein Sources 

Animal-Based Proteins 

Benefits of Whey, Casein, and Eggs 

Animal-based proteins are often considered superior due to their complete amino acid profile, which includes all essential amino acids. Here are some key benefits: 

  • Whey Protein: Whey is a fast-digesting protein that quickly delivers amino acids to the muscles. It's rich in branched-chain amino acids (BCAAs), particularly leucine, which is crucial for muscle protein synthesis (MPS). Whey is ideal for post-workout consumption due to its rapid absorption. 
  • Casein Protein: Casein is a slow-digesting protein that releases amino acids gradually over several hours. This makes it perfect for sustaining protein synthesis during periods of fasting, such as overnight. Consuming casein before bed can help reduce muscle breakdown while sleeping. 
  • Eggs: Eggs are a highly nutritious and versatile protein source. They contain all essential amino acids and are rich in vitamins and minerals. Eggs have a high biological value, meaning they are efficiently used by the body for protein synthesis. They are also easy to incorporate into meals throughout the day.

Plant-Based Proteins 

Benefits of Pea, Soy, and Other Plant Proteins 

Plant-based proteins can be an alternative for those with dietary restrictions or preferences. They can be just as effective as animal proteins when consumed in adequate amounts and combinations. 

  • Pea Protein: Pea protein is rich in BCAAs and easily digestible. It is hypoallergenic, making it suitable for individuals with allergies to dairy or soy. Although slightly lower in methionine, it can be paired with other protein sources to ensure a complete amino acid profile. 
  • Soy Protein: Soy is a complete protein, containing all essential amino acids. It is also rich in other nutrients like fibre, vitamins, and minerals. Soy protein has been shown to support muscle growth and recovery effectively. It's a versatile option for vegetarians and vegans. 
  • Other Plant Proteins: Sources such as hemp, rice, and quinoa proteins offer various benefits. While some may be incomplete proteins, combining them with other plant proteins can provide all essential amino acids.

Choosing the Right Protein for Your Clients 

Factors to Consider 

When recommending protein sources to your clients, consider the following factors: 

Dietary Preferences: Ensure the protein source aligns with your client's dietary habits, whether they prefer animal or plant-based options.

Allergies and Intolerances: Be mindful of any allergies or intolerances your client may have. For example, lactose-intolerant clients might benefit more from plant-based proteins or lactose-free whey isolates.

Goals and Training Regimen: Tailor protein recommendations based on your client’s specific fitness goals and training intensity. For example, fast-digesting proteins like whey are ideal post-workout, while slow-digesting proteins like casein are better for night time consumption. 

Blended Proteins for Sustained Release 

Blended proteins combine fast, medium, and slow-digesting proteins to provide a steady release of amino acids over an extended period. This can be particularly beneficial for clients who may not have the time or ability to consume protein every few hours.  

Blends often include whey, casein, and sometimes egg or plant proteins, offering a comprehensive amino acid profile and sustained muscle support. 

Incorporating a variety of protein sources ensures that your clients receive a balanced intake of essential amino acids, optimising muscle growth and recovery. 

Common Misconceptions About Protein 

Myth: More Protein Equals More Muscle 

One of the most pervasive myths in the fitness world is that consuming more protein will automatically lead to more muscle growth. While protein is essential for muscle repair and growth, there is a limit to how much the body can use effectively. 

Explanation of Why Excess Protein Isn't Always Beneficial 

Consuming protein beyond what your body needs doesn’t translate to increased muscle mass. Excess protein can be converted into energy or stored as fat, rather than being used for muscle synthesis. 

The Body's Upper Threshold for Protein Absorption 

Research suggests that the optimal protein intake per meal is about 20-30 grams for most individuals, depending on their body weight and activity level. Consuming significantly more than this in one sitting doesn’t provide additional benefits for muscle growth. Instead, it’s more effective to distribute protein intake evenly throughout the day. 

Myth: All Proteins Are the Same 

Another common misconception is that all protein sources are equal in terms of quality and effectiveness. This isn’t true, as different proteins have varying amino acid profiles and digestibility rates. 

Differences in Protein Quality and Effectiveness 

Proteins are evaluated based on their amino acid content and how efficiently they can be utilised by the body. Animal-based proteins generally have higher biological value because they contain all essential amino acids in the right proportions.  

Importance of Leucine and Other Amino Acids 

Leucine, an essential amino acid, plays a crucial role in muscle protein synthesis. High-quality proteins, like whey and eggs, are rich in leucine, making them particularly effective for muscle growth and recovery. Understanding these differences helps in choosing the most beneficial protein sources for specific fitness goals. 


As a personal trainer, understanding the nuances of protein intake is vital when working with clients, whether their goal is improving fitness, sports performance, or body composition. Here are the key points to keep in mind: 

Optimal Protein Intake: This varies based on individual body weight, activity level, and type of training. Tailor your recommendations to each client's specific needs. 

Even Distribution: Distributing protein intake evenly throughout the day maximises its benefits, supporting continuous muscle protein synthesis and recovery. 

Strategic Timing: Consuming protein at strategic times, such as pre and post-workout, can significantly enhance muscle protein synthesis and overall recovery. 

High-Quality Sources: Selecting high-quality protein sources, both animal-based and plant-based, ensures your clients receive all essential amino acids, particularly leucine, which is crucial for muscle growth. 

With this knowledge, you can confidently educate your clients about the benefits of proper protein intake, helping them achieve their fitness goals more effectively. 


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