This article is written by Amy from The Running Dietitian.
One of the most common questions new runners ask is how they need to change the way they eat once they begin running. Running places new demands on the body, and nutrition plays an important role in meeting those needs. That said, the changes often do not need to be extreme. Small, intentional adjustments are typically more effective and can go a long way in supporting both performance and recovery.
For new runners, nutrition can feel intimidating, especially with the abundance of conflicting advice online. The goal is not to overhaul your diet overnight, but to make practical, sustainable choices that fit your lifestyle and training.
Below, you’ll learn how to adjust your nutrition in simple ways to support your running and your everyday life – helping you feel more confident, energized, and prepared as your training progresses.
Avoiding Restriction
Many runners begin their running journey with a goal of losing weight. While this is common, it is important to understand that eating enough should be the number one priority when it comes to supporting your running. As training places new demands on the body, adequate fuel becomes essential for adapting to those demands.
When running volume increases while food intake decreases, the body often struggles to perform, recover, and maintain energy for everyday life.
This mismatch can lead to low energy availability, or LEA, which is a precursor to relative energy deficiency in sport, also known as RED-S. Both LEA and RED-S occur when the body does not receive enough calories to support the physical demands being placed on it. Common signs include fatigue, lingering soreness, poor recovery, irritability, and trouble sleeping.
Trying to change too many things at once, such as running more while cutting calories or eliminating entire food groups, can increase the risk of burnout and injury. Instead, focus on supporting your body through training. When you are consistently eating enough, your body is better equipped to adapt to training, and running performance is more likely to improve.
Adjusting Your Diet Over Time
As training volume increases, energy needs often increase as well. It is normal and expected for appetite to increase alongside training.
Hunger is your body’s way of signaling that it needs more fuel, and it can be helpful to think of hunger as information rather than something to fight against. Responding to hunger supports training, recovery between runs, and overall energy levels.
It is also important to note that running can sometimes suppress appetite, and hunger cues may not always reflect what your body actually needs. During longer runs and higher intensity workouts, the hormone that stimulates appetite is delayed, while an appetite suppressing hormone is released. As a result, you may not feel hungry immediately after a hard run despite needing calories, carbohydrates, and protein to support recovery.
In these situations, planning a post run meal or snack ahead of time can be especially helpful. Eating on a schedule while also responding to hunger cues can help ensure your body gets the fuel it needs.
Rather than overhauling your diet when you start running, begin by adjusting portions:
Add slightly more carbohydrates to meals to support training
Make sure protein is included in all your meals and snacks to support recovery
Include fats to support fullness, hormone health, and overall satisfaction
Snacks can be a useful tool to support intake, especially around workouts. Think of snacks as a bridge rather than a substitute for meals. Aim for snacks that include carbohydrates paired with protein or fat. Some top snacks include apple slices with peanut butter, energy bite balls, or yogurt with fruit and granola.
Weight: Keep It Simple
Weight will naturally fluctuate, especially when you begin running. Short term changes often reflect shifts in hydration, glycogen storage, sodium intake, or muscle inflammation, not necessarily fat gain or loss. This is especially true in the early weeks of training or when mileage increases.
Ongoing or large weight swings may be a sign that fueling and training are misaligned. In those cases, looking at meal timing and overall intake is usually more helpful than focusing on the scale alone. Paying attention to how you feel during runs, how well you recover, and your overall energy is often more informative than the number on the scale.
Key Takeaways
You do not need a diet overhaul as you start running. Eating enough supports better runs and recovery. Hunger is a normal response to training and not something to ignore. Adjust portions gradually as training increases. Weight fluctuations are common and often reflect normal physiological changes.
Nutrition should support your running, not complicate it. Focus on steady habits, flexibility, and fueling in a way that allows you to keep showing up.
If you are unsure how much or what to eat, meeting with a registered dietitian can help you learn how to fuel your body to run well.