Nutrition and Fitness: The Impact of Macronutrients on Performance
When it comes to improving athletic performance, training is only part of the equation. The other half is how you fuel your body, especially your balance of protein, carbohydrates, and fats (macronutrients). The right macro balance can support steadier energy in training, better recovery, and more predictable body composition changes over time.
In this article, we’ll break down what each macronutrient does for performance and recovery, and we’ll include practical reference points such as typical protein targets (g/kg), carbohydrate fuelling guidance (including carbs per hour for longer sessions), and a simple way to adjust macros based on your goal (strength, endurance, or fat loss)
The role of proteins in muscle recovery and growth
Protein supports muscle repair, adaptation, and recovery especially after strength training or higher-intensity sessions. For most exercising individuals, a widely cited daily intake range is 1.4 - 2.0 g of protein per kg of body weight per day, adjusted for training phase and goals.
A practical approach is to spread protein across the day rather than relying on one large meal. Many sports nutrition position papers reference 20–40 g of high-quality protein per serving (or roughly 0.25–0.40 g/kg per dose) repeated every few hours as a pattern that supports muscle protein synthesis and recovery
Food-first examples include eggs, yoghurt, lean meats, fish, tofu, legumes, and high-protein dairy chosen based on tolerance and preferences.
How much protein do you need?
- Active individuals: ~1.4–2.0 g/kg/day
- Per meal/serving: often 20 - 40 g
Carbohydrates: the body's primary energy source
Carbohydrates are the body’s most efficient fuel source for higher-intensity training, repeated efforts, and longer sessions where glycogen stores matter. Choosing mostly fibre-rich carbohydrate sources (whole grains, fruit, vegetables, legumes) supports steadier energy while faster-digesting carbs can be useful around training.
For endurance exercise lasting beyond about an hour, widely referenced guidance (including ACSM-linked recommendations) often suggests 30 - 60 g of carbohydrate per hour to support performance and reduce the risk of energy crashes
If training sessions regularly exceed two hours, some guidance notes that higher intakes (e.g., >60 g/hour) may be useful - but this should be tested in training first for gut tolerance.
Carbs per hour (endurance fuelling reference), ~30–60 g/hour for endurance exercise over ~1 hour
The Importance of Healthy Fats in a Balanced Diet
Fats support hormone production, absorption of fat-soluble vitamins, and overall cellular health which matters when you’re training consistently and placing stress demands on the body. They also provide a concentrated energy source, especially relevant for lower-intensity, longer-duration work.
The common reference range for athletes is 20–35% of total daily calories from fat. The quality of fats matters: prioritise sources like olive oil, nuts, seeds, avocado, and fatty fish, while keeping saturated fat in check as part of an overall balanced diet.
Hydration: The Unsung Hero of Performance
Hydration supports temperature regulation, nutrient transport, and recovery and even small deficits can make training feel harder than it should. Sports nutrition guidance frequently notes that performance can decline once dehydration becomes meaningful; some endurance guidance highlights risk once dehydration exceeds around ~2% body mass in many conditions.
A simple hydration routine:
- Arrive at training already hydrated (don’t “catch up” mid-session)
- Sip consistently during longer sessions
- Consider electrolytes for heavy sweating or heat, especially on longer workouts
Finding the Right Balance for Your Goals
There isn’t one perfect macro split for everyone - your ideal balance depends on training style, weekly volume, recovery needs, and your goal. It can be thought of this way:
If your goal is strength or muscle gain:
- Keep protein consistent daily (use the g/kg reference)
- Use carbohydrates to support training quality and progression
- Keep healthy fats steady for hormones and satiety
If your goal is endurance performance:
- Carbohydrates typically become a bigger lever (especially around long sessions)
- Protein supports recovery from volume
- Fats remain important, but don’t push them too low chronically
If your goal is fat loss without losing performance:
- Keep protein high enough to protect lean mass and recovery
- Don’t remove carbs so aggressively that training output collapses
- Use fats to keep meals satisfying and sustainable
Want a plan that matches your training and your lifestyle?
I’m Louis Fabre, a personal trainer in Paris, and I help people build strength, improve performance, and feel confident in their routine without following generic programmes that don’t stick.
If you’re not sure how to balance protein, carbs, and fats for your goal, I’ll create a plan that matches your training schedule, lifestyle, and preferences so you see progress you can repeat week after week.
Book your first session and let’s build a clear, realistic strategy for training, recovery, and nutrition.
