The three fueling mistakes most likely to leave new runners tired and depleted

Starting running is often simple. Fueling for it usually isn’t.

If you’ve recently taken up running and find yourself constantly tired, sore, or struggling to recover between sessions, your training plan may not be the problem.

According to Dr Linia Patel, a registered dietitian and performance nutritionist, nutrition is often the missing piece.

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Here are the most common fueling mistakes she sees in new runners—and the simple switches that can make a real difference.

Mistake 1: Not eating enough

Many recreational runners underestimate how much energy running actually demands and assume that fatigue and soreness are part of training. In reality, that’s not always the case.

“Persistent fatigue, poor recovery between sessions, heavy legs, low mood and struggling to hit usual training paces can all indicate that your body isn’t getting enough energy to support both training and everyday life,” says Patel.

When the body doesn’t receive enough fuel, it enters a state known as low energy availability. “Think of it like your phone switching to power-saving mode when the battery is low,” she explains. “The body starts conserving energy by reducing functions that aren’t immediately essential for survival.”

Fueling tip: If you’re regularly feeling drained after runs, look beyond your training schedule and consider whether you’re eating enough throughout the day to support both exercise and everyday life.

Mistake 2: Avoiding carbohydrates unnecessarily

Carbohydrates have been unfairly demonised in recent years, but they’re the body’s preferred fuel source during running.

“When carbohydrate stores are low, runners often experience fatigue, reduced performance, slower recovery and a higher perception of effort during training,” says Patel.

The trick is choosing the right types. One of the most common misconceptions, says Patel, is assuming all carbohydrates are equal. She recommends building your diet around nutrient-rich carbohydrates such as oats, wholegrain bread, potatoes, sweet potatoes, beans, lentils and other wholegrains, because these provide sustained energy alongside fiber, vitamins and minerals.

“For runners, the question shouldn’t be whether to eat carbohydrates, but rather choosing the right types and eating enough of them to support training,” says Patel. “A well-fueled runner will almost always perform, recover and feel better than one trying to train on an empty tank.”

Fueling tip: Include carbohydrate-rich foods regularly throughout the day—not just around your runs—to help support energy levels and recovery.

Mistake 3: Neglecting hydration

If Patel could encourage new runners to focus on just one habit, it would be to drink water regularly throughout the day.

“Hydration underpins almost every aspect of performance and wellbeing,” she says.

Being properly hydrated can support recovery, temperature regulation, energy levels, concentration and mood. Even mild dehydration can make a run feel harder than it should and may negatively affect performance.

That’s why Patel recommends starting every run well hydrated, rather than trying to catch up on fluids once you’re already exercising.

Fueling tip: Check the color of your urine before heading out for a run. Pale straw-colored urine generally indicates good hydration, while darker urine may be a sign that you need to drink more fluids.