Feeling tired during the day isn't always due to lack of sleep or willpower.
Often, how and when we eat—as well as what we eat—can have a big impact on both our physical and mental energy levels. The best part? You don’t need a perfect diet. Just focus on a few key habits, and you’ll feel more alert and focused all day long.
When the Fatigue is Mental
When you experience difficulty concentrating, a sensation of 'brain fog,' or poor cognitive performance, you are likely suffering from
mental fatigue. This often results from:
Meals high in simple sugars
Long periods without eating
Lack of essential micronutrients
What changes help:
Prioritizing breakfasts and meals with protein (eggs, yogurt, legumes, fish)
Including complex carbohydrates (oats, whole grain bread, legumes) instead of refined ones
Adding
healthy fats (nuts, seeds, olive oil)
Tip for you: Skip starting your day with just coffee and sweets! Try adding protein and fiber to keep your mind sharp all morning.
When the Fatigue is Physical
Physical fatigue manifests as reduced strength, fatigue, or poor performance when moving. It may be related to:
Insufficient caloric intake
Iron, magnesium, or potassium deficiency
Poor meal distribution throughout the day
What changes help:
Eating regularly to avoid "running on empty."
Including iron‑rich foods (legumes, nuts, lean meats)
Staying adequately hydrated, even without feeling thirsty
Practical tip: Planning a nutritious snack before long workdays or workouts improves physical endurance.
Afternoon Energy Crashes
Typically, the classic afternoon 'slump' strikes after heavy meals or those high in refined carbohydrates, which elevate blood sugar quickly, only to cause rapid drops soon after.
What changes help:
Replacing ultra‑processed snacks with:
Practical tip: Preparing your snack in advance prevents impulsive food choices when fatigue kicks in.
Why These Changes Work
More stable energy
A balanced diet helps regulate blood sugar levels, avoiding sharp rises and falls that can cause fatigue.
Key micronutrients
B vitamins, iron, magnesium, and zinc all play a role in energy metabolism. A deficiency in any of them can lead to persistent tiredness.
Fewer spikes, fewer crashes
Combining carbohydrates with protein, fiber, and healthy fats extends energy availability and reduces feelings of exhaustion.
The bottom line
You don’t need perfection—just consistency. Fuel up, respect your mealtimes, and always have a plan for energy emergencies. With a few simple tweaks, you’ll keep your energy soaring!
This article was produced by Tomás Vicente, a journalist specializing in Health.
Sources consulted: Centers for Disease Control and Prevention (CDC), World Health Organization (WHO), Harvard Health Publishing, and scientific studies.