Macro Tracking for Runners and Endurance Athletes

TL;DR

• Endurance athletes need significantly more carbohydrates than the average person (5 to 10g per kg bodyweight depending on training volume)
• Protein is still important for recovery, even if you’re not trying to build muscle. Aim for 1.4 to 1.8g per kg
• Undereating is a bigger risk than overeating for most runners. Relative Energy Deficiency in Sport (RED-S) is a serious concern
• Timing matters more for endurance athletes than for most people. Pre-run and post-run nutrition can significantly affect performance and recovery
• Track your intake with Chowdown to make sure you’re actually fuelling your training adequately

Most macro tracking advice is written for people who want to lose fat or build muscle in the gym. If you’re a runner, cyclist, swimmer, or any kind of endurance athlete, the standard advice doesn’t quite fit.

Your body has different demands. You burn through more fuel, need more carbohydrates, and face unique risks like underfuelling and overtraining. Getting your macros right isn’t about aesthetics. It’s about performance, recovery, and staying healthy enough to keep training.

Here’s how to approach macro tracking as an endurance athlete.

Why Endurance Athletes Need Different Macros

The average person doing three gym sessions a week might burn an extra 600 to 900 calories through exercise. A marathon runner in peak training might burn an extra 1,500 to 2,500 calories on a long run day. The scale of energy demand is completely different.

This changes everything about your macro requirements:

• Carb needs increase dramatically because glycogen (stored carbs) is your primary fuel during sustained effort
• Protein needs remain moderate to high because endurance exercise still causes muscle damage that needs repair
• Fat needs stay relatively standard but shouldn’t be cut too low, as fat is an important fuel source during lower-intensity efforts
• Total calorie needs are much higher than most people realise

Carbohydrates: Your Primary Fuel

During endurance exercise, your body primarily burns glycogen (stored carbohydrates) and fat. At higher intensities, the reliance on glycogen increases. During a hard tempo run or race, you might be burning carbs at a rate of 60 to 90g per hour.

Your body can store roughly 400 to 500g of glycogen in muscles and liver. That’s enough for about 90 minutes to 2 hours of moderate-to-hard effort. After that, you “hit the wall” as glycogen runs out, and performance drops dramatically.

How Many Carbs Do You Need?

Training Volume	Carb Target (per kg bodyweight)
Light training (30-60 min/day)	3-5g/kg
Moderate training (1-2 hours/day)	5-7g/kg
Heavy training (2-3 hours/day)	7-10g/kg
Extreme (3+ hours/day or multi-session)	10-12g/kg

For a 70kg runner doing 60-90 minutes of running most days, that’s 350 to 490g of carbs per day. That’s a lot more than the 150 to 250g most general nutrition advice suggests.

Carb Sources for Runners

Not all carbs are equal when it comes to fuelling performance:

Before runs (2-3 hours before): Moderate GI, easy to digest. Porridge, toast with banana, rice cakes with honey.

During runs (over 60 minutes): High GI, fast-absorbing. Energy gels, sports drinks, jelly babies, dried fruit.

After runs: Mix of high and moderate GI to replenish glycogen. Rice, pasta, potatoes, fruit, plus protein for recovery.

Protein: Recovery and Adaptation

Endurance athletes don’t need as much protein as powerlifters, but they need more than people think. Running causes significant muscle damage, especially during long runs and downhill efforts. Protein is essential for repair.

Target: 1.4 to 1.8g per kg bodyweight. A 70kg runner should aim for 98 to 126g per day.

Protein Timing for Recovery

Unlike the general population where meal timing barely matters, endurance athletes benefit from strategic protein timing:

• Within 30-60 minutes post-run: 20 to 30g of protein to kickstart recovery
• Evenly distributed across meals: 25 to 35g per meal for sustained muscle protein synthesis
• Before bed: A casein-rich snack (like Greek yoghurt or cottage cheese) provides slow-release protein overnight when your body does most of its repair work

For more on protein targets, see our protein needs guide.

Fat: Don’t Cut It Too Low

Fat is essential for:

• Hormone production (low fat intake can suppress testosterone and oestrogen)
• Absorption of fat-soluble vitamins
• Energy during low-intensity exercise (fat is a major fuel source during easy runs)
• Joint health and inflammation management

Target: 1.0 to 1.5g per kg bodyweight. Don’t go below 0.8g/kg.

Endurance athletes who cut fat too aggressively often experience hormonal disruption, increased injury risk, and poor recovery. This is especially common in female runners.

The Underfuelling Problem

The biggest nutritional risk for endurance athletes isn’t eating too much. It’s eating too little.

Relative Energy Deficiency in Sport (RED-S)

RED-S occurs when your energy intake doesn’t match your energy expenditure over time. It affects everything:

• Hormonal function (irregular or absent periods in women, low testosterone in men)
• Bone health (increased stress fracture risk)
• Immune function (getting ill constantly)
• Mental health (mood changes, poor concentration)
• Performance (paradoxically, undereating makes you slower, not faster)

RED-S is surprisingly common among recreational runners who track calories with a “less is better” mentality. You cannot outrun insufficient fuel. Your body will break down.

Signs You’re Underfuelling

• Frequent illness or infections
• Stress fractures or recurring injuries
• Feeling tired despite adequate sleep
• Poor performance that doesn’t improve with more training
• Irregular menstrual cycle (women)
• Loss of morning appetite
• Mood changes, irritability, low motivation

If several of these apply, increase your calories by 300 to 500 and see a sports dietitian.

How to Track Macros as a Runner

Use a Photo-Based Tracker

When you’re running 50+ miles a week, you don’t want to spend 20 minutes a day manually logging food. Chowdown lets you snap photos of meals and get instant macro estimates. Quick, easy, and accurate enough to spot underfuelling patterns.

Track Trends, Not Perfection

Day-to-day accuracy matters less than weekly patterns. Some days you’ll eat more (long run days), some less (rest days). What matters is that your weekly average meets your needs.

Separate Training Days from Rest Days

Consider having different macro targets for different days:

Training day (70kg runner, 90-minute run):

• Carbs: 7g/kg = 490g
• Protein: 1.6g/kg = 112g
• Fat: 1.2g/kg = 84g
• Total: ~3,200 calories

Rest day:

• Carbs: 4g/kg = 280g
• Protein: 1.6g/kg = 112g
• Fat: 1.2g/kg = 84g
• Total: ~2,360 calories

This carb cycling approach matches fuel to demand without overcomplicating things.

Don’t Forget Fuelling During Runs

If you run for more than 60 minutes, you need to consume carbs during the run. This isn’t optional for performance. Aim for 30 to 60g of carbs per hour during runs over 60 minutes, and up to 90g per hour for runs over 2.5 hours (using mixed glucose/fructose sources).

Log these too. Gels, sports drinks, and snacks consumed during training are part of your daily intake.

Practical Meal Ideas for Runners

Pre-Run Breakfast (2-3 hours before)

• Porridge with banana and honey: ~60g carbs, 12g protein
• Toast with peanut butter and jam: ~55g carbs, 14g protein
• Rice cakes with honey and a banana: ~70g carbs, 4g protein

Post-Run Recovery Meal

• Chicken and rice with vegetables: ~65g carbs, 40g protein
• Tuna pasta with tomato sauce: ~75g carbs, 35g protein
• Smoothie with banana, protein powder, oats, and milk: ~55g carbs, 35g protein

High-Carb Dinner

• Spaghetti bolognese with garlic bread: ~90g carbs, 35g protein
• Chicken stir-fry with noodles: ~80g carbs, 40g protein
• Fish and chips with mushy peas: ~85g carbs, 30g protein

For more meal ideas, check out our high protein meals under 500 calories (though as a runner, you’ll likely want to add carb-heavy sides). If you’re looking for vegetarian options, see our high-protein vegetarian meals guide.

Race Week Nutrition

In the week before a race, carbohydrate loading can improve performance by topping off glycogen stores:

• 3-4 days before race: Increase carbs to 8 to 10g per kg
• Day before race: 10 to 12g per kg, low fibre to avoid GI issues
• Race morning: Familiar breakfast, 2 to 3 hours before start. 1 to 2g carbs per kg

Track your intake during race week to make sure you’re actually hitting these targets. It’s surprising how hard it is to eat 10g/kg of carbs. You need to be deliberate about it.

The Bottom Line

Macro tracking for endurance athletes is fundamentally different from tracking for fat loss or bodybuilding. The priorities are:

1. Eat enough. Underfuelling is the most common and most damaging mistake
2. Prioritise carbs. They’re your primary fuel, not the enemy
3. Maintain adequate protein. Your muscles need it for recovery
4. Don’t cut fat too low. Hormones and health depend on it
5. Match fuel to demand. Eat more on hard training days, less on rest days

Use Chowdown to track your intake and make sure you’re actually fuelling your training. Running on empty doesn’t make you leaner. It makes you slower, more injury-prone, and unhealthier.

If you’re new to macro tracking, start with our macro tracking for beginners guide to learn the basics. For more advanced strategies, check out our common macro tracking mistakes article to avoid common pitfalls.

Fuel the work. Track the fuel. Run faster.