When crafting an effective nutrition plan, especially for those focused on muscle growth and fat loss, it's crucial to understand the finer details of protein and carbohydrate intake. Here’s a detailed breakdown of the latest research and recommendations to help you tailor your dietary approach.
Protein Intake: Beyond the 20-25g Myth
A common misconception is that consuming more than 20-25g of protein per meal results in the excess being wasted, either excreted as urea or burned as fuel. This idea, known as the “muscle full” theory, suggests a blanket protein recommendation per meal regardless of individual differences. However, recent research offers a more personalised approach.
Brad Schoenfeld and colleagues (2018), in a study published in the Journal of the International Society of Sport Nutrition, recommend consuming 0.4-0.55g of protein per kg of bodyweight per meal, spread across at least four meals per day. This personalised approach ensures more efficient protein utilisation, particularly for muscle synthesis. Notably, Moore et al. (2015) added that older adults might require as much as 0.6g/kg/bodyweight per meal to achieve the same anabolic response.
The rate of protein absorption plays a significant role in determining how much protein can be efficiently used per meal. For example, “fast-acting” whey protein is absorbed at a rate of approximately 10g per hour (Bilsborough and Mann, 2006), meaning a 20g protein shake is fully digested in about two hours. In contrast, whole food proteins like those found in eggs have a slower absorption rate, around 3g per hour, allowing for greater protein uptake over time. When combined with carbohydrates and fats, as in a balanced meal, protein absorption is further delayed, enabling the body to utilise larger amounts of protein effectively.
Carbohydrate Intake: Fueling Performance and Recovery
The role of carbohydrates in resistance training and recovery cannot be understated. The glycolytic system, responsible for energy production during high-intensity activities lasting from 10 to 75 seconds, relies heavily on glucose (carbohydrates) to function optimally. Research indicates that glycolysis can account for up to 82% of the energy used during resistance training sessions (MacDougall et al., 1977), making adequate carbohydrate intake crucial for maintaining performance.
The average muscle glycogen content ranges from 300-700g, with a typical resistance training session depleting glycogen stores by up to 40% (Koopman et al., 2006). To replenish these stores, Murray and Rosenbloom (2018) recommend consuming 1-1.2g of carbohydrates per kg of body weight in post-workout meals. This timing is critical, as muscle glucose uptake and insulin sensitivity are significantly heightened immediately after training, facilitating faster glycogen restoration.
Balancing Macronutrients for Specific Goals
When it comes to balancing protein, carbohydrates, and fats, the primary considerations should be overall calorie balance and protein intake. However, additional factors such as adherence, food preferences, and satiety also play a role in the effectiveness of a diet plan.
It’s possible to train for fat loss, muscle gain, and endurance simultaneously, but the strategies may conflict depending on the primary goal. For example, if fat loss is a priority, a higher fat intake (over 40% of total calories) can be beneficial. This approach not only supports the production of androgen hormones, which play a role in muscle growth and fat metabolism, but also reduces insulin levels, thereby promoting fat breakdown through the activation of hormone-sensitive lipase (HSL).
In contrast, a carbohydrate-focused diet may be more appropriate for endurance athletes or those prioritising glycogen replenishment and sustained energy during prolonged exercise.
Key Takeaways
Protein Intake: Aim for 0.4-0.55g of protein per kg of bodyweight per meal, spread across four or more meals daily. Adjust this to 0.6g/kg for older adults to maximise muscle protein synthesis.
Carbohydrate Timing: Post-workout, consume 1-1.2g of carbohydrates per kg of body weight to replenish glycogen stores and support recovery.
Macronutrient Balance: Align your macronutrient intake with your specific goals—prioritise carbohydrates for performance and recovery, or fats for enhanced fat loss and hormonal balance.
By understanding and applying these principles, you can create a nutrition plan that supports your training goals while optimising muscle growth and fat loss.
For personalised guidance tailored to your needs, feel free to reach out to me at paul@thenutritionistuk.com or follow my latest insights on Facebook.
As a Qualified Registered Nutritionist, I’m here to help you achieve your health and fitness goals effectively.

There are endocrine implications to consider, namely the interplay of insulin and glucagon. Insulin is anabolic and protein-sparing. However, if it remains chronically elevated through a diet rich in carbohydrates, the breakdown of fat will be hindered. Once circulating insulin falls below a certain threshold glucagon output increases and with it the concomitant release of HSL (hormone sensitive lipase). This key enzyme is required for effective fat loss. A high fat diet, north of 40% of total calories, has the added benefit of increasing androgen production, enhancing the cumulative effect on body composition by suppressing further fat storage (Volek et al., 1997).