Fueling Performance and Recovery: Understanding Glucose, Insulin, and Energy

If you have followed a well structured training plan, increased your training load efficiently but still felt flat in your sessions, struggled to recover, or hit a wall with weight loss or muscle gain, there’s a good chance it’s not your training plan holding you back, it’s how you’re fueling your body.

You don’t need to obsessively count every calorie or live on a restrictive diet to get results. But having a basic understanding of how your body uses energy, from calories to glucose to recovery, can completely change how you train, perform, and feel.

This isn’t about chasing perfection. It’s about learning how food, energy, and recovery all work together so you can train smarter, recover faster, and get better results.

1. Nutrition Basics: Energy In vs Energy Out

Let’s start with the big picture:
Your body runs on energy. That energy comes from food, measured in calories.

• Calories in = what you eat.

• Calories out = what you burn through movement, exercise, and basic daily functions.

If you want to lose fat, you need to be in a calorie deficit over time.
If you want to gain muscle, you generally need a slight surplus.
And if you want to maintain performance and recovery, you need to at least meet your baseline needs.

Here’s the thing though, you don’t need to track every bite to make progress. But if you have no idea what your body roughly needs, you’re guessing.

Know Your Baseline

At the very least, it helps to understand your BMR, your basal metabolic rate.
That’s how many calories your body burns just to keep you alive, before training, before walking, before doing anything.

Stack your training and activity on top of that, and you’ve got your TDEE (total daily energy expenditure).
If you don’t have a rough idea of those numbers, you’re navigating nutrition blindfolded.

2. Beyond Calories: How Food Quality Shapes Results

Calories are the foundation, but they’re not the whole story.
What you eat and how your body handles it matters too.

This is where glucose sensitivity and insulin resistance come in.

• Your body gets energy from all the food you eat, but carbs are converted into glucose the easiest and quickest. Glucose is the body’s preferred energy source, especially for fuelling your workouts and speeding up recovery. Protein and fats play their roles too, but carbs are key for performance
  

• Insulin, a key hormone, acts like the “unlocking mechanism” that lets glucose enter your muscles to be used for energy or stored for later.

• When you’ve got good glucose sensitivity, your body handles carbs efficiently, this leads to steady energy, better recovery, improved performance.

• When you become insulin resistant, your body struggles to move glucose into the muscles, meaning more gets stored as fat, recovery slows, and energy dips.

3. Training, Recovery, and Glucose Control

The good news? You can train your body to become more glucose sensitive meaning it uses fuel more efficiently.

• Resistance Training - Building muscle gives your body more “storage tanks” for glucose for more energy and more efficient recovery.

• Conditioning Work - Aerobic and interval training make your muscles better at pulling in glucose for fuel.

• Carb Timing - Eating carbs around training means they’re more likely to be used for energy and recovery rather than stored. This is especially important after exercise, when your muscles are primed to replenish glycogen stores and get into some recovery.

• Sleep and Stress - Poor sleep and constant stress reduce glucose sensitivity, even if your training’s solid.

It all ties together: the way you train, recover, and fuel your body dictates how efficiently your system runs.

4. Practical Signs Your Glucose Sensitivity Might Be Off

• Constant energy crashes during the day

• Strong carb or sugar cravings

• Struggling to see changes in body composition despite training consistently

• Feeling flat or sluggish in sessions

• Slow recovery even with good programming

If any of this sounds familiar, trying to improve glucose sensitivity could make a huge difference, not just for body composition, but for performance and recovery too.

5. Practical Steps to Improve Glucose Sensitivity

• Train consistently - both strength and conditioning matter.

• Stay active outside the gym - even walking after meals helps.

• Prioritise protein and whole foods - keeps energy stable and cravings down.

• Time your carbs around training - fuel performance, not fat storage.

• Dial in sleep and stress management - both massively impact insulin response.

Understanding calories, food quality, and glucose sensitivity isn’t about tracking everything perfectly or living on a restrictive diet.

It’s about having the awareness to make better decisions and fuel your body to match your goals.

• Calories are your foundation.

• Food quality and glucose control drive performance and recovery.

• Training, sleep, and stress all influence how efficiently your body uses fuel.

Get those moving together, and you’ll not only train better but feel better, recover faster, and get results that last.

Train with intent. Fuel with purpose. Recover well.
That’s how you climb.