Nutrition 101 And Fueling For Your Training

So, you’re about to kick off a new training regimen. Whether it's climbing, running, cycling, or swimming, if your plan includes ramping up volume, frequency, or intensity, chances are you’ll be burning more calories.

The Risks of Under-Fueling

Athletes often underestimate how much fuel they need when starting a new program (Loucks, 2007). Under-eating can disrupt sleep, affect mood and stress levels, and reduce recovery capacity, all of which increase the risk of injury (Coelho et al., 2021). Think of your body like a race car: it can perform at high speeds, but without the right fuel and maintenance, it’s headed for a breakdown.

How to Fuel More Without Eating More

The obvious solution is to eat more calories (Monjoy et al., 2014). But how do you do that without increasing the overall volume of food, especially if you struggle with appetite or digestive discomfort? First, we need to understand a few foundational concepts:

Key Concepts: Calories, Caloric Density, Water Content, and Macronutrients

• Calories: In both physics and nutrition, a calorie is simply a unit of energy. Bigger or more active individuals typically require more calories to maintain weight and function (Hill et al., 2012).

• Caloric Density: This refers to how many calories are packed into a gram of food. For example, butter has ~717 kcal per 100g, while celery has only 8 kcal per 100g. What affects caloric density? Two major factors: water content and macronutrient makeup. (CDC, 2008)

• Water Content: Water adds volume and weight without calories. Celery is ~95% water, butter ~16–18%. High water = low caloric density.

• Macronutrients: Protein, fat, and carbohydrates are all macronutrients, and differ in energy per gram. Carbs and protein have ~4 kcal/g; fat has ~9 kcal/g (USDA, 2021). So the more fat a food contains (with water content held constant), the more calorically dense it will be.

Why Increasing Calories Can Be Hard

Some athletes struggle to eat more due to reduced appetite, time constraints, or discomfort. Eating too close to a session can lead to bloating or sluggishness. The solution? Boost calories without increasing food volume, mainly by focusing on higher caloric density.

But First, Diet Quality

Yes, you could just eat cake and chips to hit your calorie goals — and technically maintain weight (Hill et al., 2012). But when training increases, so does your need for nutrients and protein.

Processed foods are fine in moderation and can satisfy cravings, but they often lack the nutritional firepower needed for recovery. A diet rich in high-quality, nutrient-dense, protein-packed foods is crucial for building muscle, replenishing glycogen, and avoiding injury.

Tactics to Increase Calories Without More Volume

1. Increase Fat Intake

Fats are calorie-dense and flavorful. Adding fat to meals is one of the simplest ways to bump up calories without expanding your plate. Common sources are oil, butter, nuts, seeds, avocado, full-fat dairy, and fatty meats.

Tips:

• Generously oil veggies before roasting

• Add nut butters to smoothies, oats, or toast

• Sprinkle roasted nuts on salads

• Add avocado or cheese to your usual meals

• Experiment with different oils (olive, coconut, ghee, etc.)

Note: Don’t replace carbs or protein with fat, just add to them. Both carbs (for glycogen) and protein (for repair) are essential, especially during heavy training blocks (Alghannam et al., 2018; Burke et al., 2004).

2. Use Quick Carbohydrates

Simple carbs like sugar, honey, and fruit, are easy to digest and deliver fast energy. They’re ideal before or during training, when you want energy without feeling full (Holesh et al., 2023).

Quick Carb Ideas:

• Energy gels or chews

• Jelly beans or other candies

• Fruit (especially at meals away from training)

• Honey (drizzled on oats, yogurt, toast, or in tea)

Note: Fructose (like in fruit) doesn't replenish muscle glycogen as efficiently as glucose, so save it for meals not close to training.

3. Drink Your Calories

Liquid calories are a powerful tool. They’re easy on the stomach, quick to digest, and often less filling than solids (Cleveland Clinic, 2021). Examples include smoothies, protein shakes, Gatorade, electrolyte mixes, and milk or juices.

Smart Liquid Calorie Ideas:

• Protein shakes with nut butter, seeds, or honey

• Smoothies packed with fruit, oats, or full-fat yogurt

• Sports drinks with carbs and electrolytes during longer sessions

Note: Be mindful of sugar content in some commercial beverages and balance them with nutrient-dense options.

Combinations = Power Moves

Mix and match tactics for even better results:

• Add nut butter or oil to your smoothie

• Sweeten yogurt with honey and top with granola

• Use a carb-rich drink during training and a high-fat meal afterward

Experiment, adjust, and find what works best for you.

Increasing your calories doesn’t have to mean stuffing yourself or compromising your training. With a solid understanding of caloric density and a few smart tactics, you can fuel up efficiently and recover faster without feeling like you're eating a mountain of food. Remember: there’s no single “right” approach. Try different combos, see how your body responds, and adjust as needed. The goal is performance and sustainability.

TL;DR

• Training more? You probably need more calories.

• Eat more without eating more volume by increasing caloric density.

• Focus on adding healthy fats, quick carbs, and liquid calories.

• Nutrient-dense foods matter — don’t rely solely on processed snacks.

• Mix and match strategies to meet your needs without discomfort.