Macronutrients: The What, Why, When and How.
- Joseph Thirkhill
- Oct 3
- 6 min read
Updated: Oct 10
Before we begin... if you haven’t yet read our Fundamentals of Nutrition guide, or Energy Balance, The Blueprint Behind Fat Loss, Muscle Gain & Peak Performance, where we introduce the concept of energy balance, how to build a sustainable plan that works for you, and the 80/20 rule for eating—head over to the Fitness Hub to get started.
It’s a great place to begin before diving into understanding macronutrients and how they shape your results.
Before We Talk Macros, Here's What You Need to Know.
To understand macronutrients, we first need to understand calories and energy balance, which is pretty much the foundation of every successful training and nutrition strategy.
Your daily calorie needs. Where do they come from?
BMR (Basal Metabolic Rate) This is the energy your body burns to stay alive, think breathing, organ function, and all the things happening under the surface, even when you're at rest.
TDEE (Total Daily Energy Expenditure). This builds on your BMR, factoring in movement, workouts, steps, and general daily activity.
TEF (Thermic Effect of Food). This is the energy your body uses to digest food.
Once you know your calorie needs, what do you need to do to align with your goal?
Fat loss: Eat 10–20% below that number.
Muscle gain: Eat 10–20% above it.
Maintenance: Stay consistent at your TDEE.
With your calorie target in place, the next step is to break those calories down into the right macronutrient balance, and this is what turns general nutrition into goal-driven nutrition.
What Are Macronutrients?
Macronutrients are, quite simply, protein, carbohydrates, and fats, the nutrients your body needs in large amounts. They provide energy (calories) and each plays a specific role in supporting your training, recovery, and overall health.
These include:
Macronutrient | Primary Functions | Examples |
|---|---|---|
Protein | Muscle repair, enzymes, hormones. | Chicken, tofu, eggs. |
Carbohydrates | Energy, brain fuel | Rice, bread, fruit. |
Fats | Hormone production, satiety, and cell health. | Avocado, nuts, olive oil. |
Alcohol | Energy-dense, non-essential. | Wine, Beer. |
Protein: The Builder
Protein is probably the most talked about macronutrient, and for good reason. It plays a vital role in building and repairing muscle, supporting your immune system, producing enzymes and hormones, and helping you feel fuller for longer.
Protein is made up of amino acids, which are known as the building blocks of your body. There are 20 amino acids that your body needs to function properly; 9 are classed as essential amino acids that must be obtained from your diet, whilst the remaining 11 are nonessential because the body can make them on its own.
Animal-based proteins (chicken, fish, eggs, dairy) and some plant sources (soy, quinoa) are considered complete proteins, as they contain all 9 essential amino acids.
What about plant-based options?
Beans, lentils, nuts, seeds, and whole grains are often incomplete proteins, meaning they’re missing one or more essential amino acids. But here’s the good news - your body is pretty clever.
As long as you eat a variety of plant-based protein sources throughout the day, your body can combine the amino acids from different foods to make what it needs. For example, rice and beans are incomplete on their own, but together, they form a complete protein.
So whether you eat meat, plants, or a mix of both, the key is variety and consistency over time.
Protein Overview:
4 kcal per gram
Key roles: Muscle repair, hormones, satiety (feeling full)
Sources: Meat, fish, dairy, tofu, beans, lentils, quinoa
Daily target: 1.2–2.2g per kg of your body weight
Carbohydrates: Your Body's Primary Fuel Source.
Carbohydrates are your body’s go-to energy source, especially when it comes to fuelling your brain, your muscles, and your training. When you eat carbs, your body breaks them down into glucose, which is then used for immediate energy or stored in your muscles as glycogen.
Think of glucose like rocket fuel: fast, accessible, and powerful when you need to perform.
But not all carbs are created equal.
Simple carbohydrates (like fruit, honey, and sports drinks) are digested quickly and provide a rapid energy boost. Useful before workouts when you need fast-access fuel.
Complex carbohydrates (such as oats, rice, potatoes, and vegetables) are made up of longer sugar chains. These take longer to digest, giving a more sustained release of energy and helping you stay fuelled and satisfied throughout the day.
Timing Matters.
The timing of your carbohydrate intake can make a big difference in your performance and recovery.
Before training. Carbohydrates give your muscles the energy they need to perform at their best.
After training. They help replenish glycogen stores, which are your muscles’ energy reserves, and support recovery.
Carbs are not the enemy, despite what the media tells us. In fact, when used strategically, they’re one of your greatest allies, particularly if your goals include improved performance, strength, or body composition.
Choosing whole, nutrient-dense carbohydrate sources also helps regulate energy levels and manage cravings, making it easier to stay consistent with your nutrition overall!
Carb Overview:
4 kcal per gram
Key roles: Energy, brain function, glycogen replenishment
Sources: Whole grains, fruit, oats, potatoes, rice
Best use: Around training sessions to optimise fuel and recovery
Fats: The Underappreciated Essential
Despite the looong-standing rumours that fats cause weight gain and poor health, the truth is that fats are vital, not optional.
Why Fats Matter
Fats are crucial for hormone production, including key hormones like testosterone and oestrogen, which influence everything from metabolism to muscle development and mood.
They help form the structure of your cells and support the absorption of fat-soluble vitamins A, D, E, and K, essential for bone health, immune function, skin repair, and more.
AND you feel fuller after meals, reducing the urge to open the snack cupboard!!
Focus on Quality, Don't Fear Fats!
The key with fat intake is not to eliminate it but to prioritise quality and aim for balance.
Unsaturated fats, found in foods like olive oil, nuts, seeds, avocado, and oily fish, are considered heart-healthy and anti-inflammatory. These should form the bulk of your fat intake.
Saturated fats, found in foods like red meat, butter, and cheese, are not inherently bad, but they should be eaten in moderation.
Trans fats, found in some processed and packaged foods, are generally best avoided!
A low-fat diet can leave you with low energy, hormonal imbalance, and poor nutrient absorption, especially if you're training regularly. Including the right fats in the right amounts helps keep your body running smoothly, consistently, and resiliently.
Fats Overview:
Calories per gram: 9
Main roles: Hormone production, brain and cell health, satiety, vitamin absorption
Sources: Avocado, olive oil, nuts, seeds, oily fish, full-fat dairy
Top tip: Don’t avoid fats, focus on quality and balance across your meals
Why Macronutrients Matter.
The number of calories tells us how much energy we’re consuming and macros tell us where that energy is going and how your body will use it. A calorie deficit will help with fat loss, but if your protein is too low, you’ll lose muscle along the way. To build muscle, you need to fuel performance with adequate carbohydrates. For health and recovery, fats need to be present and balanced.
It’s not just about eating less or more; it’s simply about learning how to eat with purpose.
Macro Splits by Goal.
Your macro split should reflect your training phase and performance needs:
Goal | Protein | Carbohydrates | Fats | Strategy. |
|---|---|---|---|---|
Maintenance | 30% | 40% | 30% | Balanced to maintain health and performance. |
Muscle Development | 25-30% | 45-55% | 15-25% | Higher carbs to fuel training and growth. |
Strength | 30% | 40-50% | 20-30% | Moderate fat, high protein and carbs. |
Fat Loss | 35-40% | 25-35% | 20-30% | High protein to protect lean mass. |
Endurance training | 15-20% | 55-65% | 20-25% | Higher carbs for sustained energy output. |
Note: Alcohol isn’t included in macro splits. If you drink, aim to keep intake below 14 units per week.
When Should You Eat Your Macros?
Timing your meals around your training can enhance performance and recovery, but don’t overthink it. What matters most is consistency over time, not perfect timing.
General Tips:
Pre-Workout (30–120 minutes before): Have a small balanced meal or snack with carbs and protein, that's low in fat: Try Greek yoghurt with fruit, or toast with honey and a protein shake.
Post-Workout (within 2 hours): Focus on carbs and protein to kickstart muscle repair and recovery: Go for chicken and rice, tofu stir-fry, or a protein smoothie with banana.
Throughout the day:
Eat protein consistently. 20–40g every 3–4 hours if possible, will support muscle protein synthesis.
If your goal is fat loss, keep carbs moderate and prioritise high-fibre veg.
For muscle growth or performance, stick with the protein and add in a handful or two of carbs with most meals.
How to put Macros into practice.
Calculate your target calories (BMR × TDEE) Head to our Energy Balance blog if you're unsure on this bit >> Energy Balance
Select your macro ratio based on your goal.
Track your intake using tools like MyFitnessPal.
Meet with your Fitness Collective coach to review progress every 2–4 weeks and make small adjustments.
Be flexible and don't put too much pressure on yourself. Think long-term consistency over perfection.
Need Help with Your Macro Plan?
Whether your goal is fat loss, building lean muscle, or increasing your energy in the gym, at our West Bridgford personal training gym, we're here to guide you every step of the way. Already a member - grab a 1:1 Nutrition Consultation with your TFC Coach today for a personalised macro breakdown based on your goals, lifestyle, and training.
At The Fitness Collective, we don’t guess, we assess, we personalise, and we help you build habits that deliver real progress and lasting results. Not training with us yet? Click below to claim your free session and start your journey with The Fitness Collective today.