Foods that cause fatigue might be hiding in plain sight on your plate. Ever noticed how certain meals leave you wanting to crash on the couch? That mid-afternoon slump might not just be about your sleep schedule—it could be coming straight from what you’re eating.

Your energy levels and what you eat are dance partners in the daily rhythm of life. While we often focus on foods that boost energy, knowing which ones might be secretly draining your battery is just as important.

Let’s explore the foods that cause fatigue and make you feel more “nap time” than “game time,” and how simple tweaks to your diet can help you maintain steady energy throughout your day.

How Foods That Cause Fatigue Affect Your Body

Before diving into specific foods, it helps to understand why what you eat impacts how you feel. Your body is constantly converting food into fuel, but not all fuel burns the same way.

Think of your metabolism like a campfire. Some foods are like kindling that creates a quick, bright flame before quickly burning out (hello, sugar rush!). Others are like slow-burning logs that provide steady, consistent heat for hours.

When your diet consists mainly of “kindling” foods, you experience those frustrating energy crashes that leave you reaching for another quick fix—creating a cycle that’s tough to break.

Ultra-Processed Foods: The Energy Vampires

That convenient packaged snack might save you time, but it could be costing you your afternoon productivity.

Ultra-processed foods set you up for energy failure in several ways:

• They trigger inflammation throughout your body, which has been directly linked to increased fatigue
• They lack essential nutrients needed for your cells to produce energy efficiently
• They often contain refined sugars that send your blood glucose on a rollercoaster ride

The science is clear: these foods disrupt normal metabolic processes and affect multiple body systems, including neurological and immune function. The result? That persistent tired feeling you can’t seem to shake.

The Worst Offenders

If steady energy is your goal, consider limiting these common ultra-processed items:

• Packaged snack cakes and cookies
• Many breakfast cereals
• Fast food meals
• Microwaveable convenience foods
• Chips and similar snack foods

The Blood Sugar Rollercoaster

Nothing tanks your energy quite like unstable blood sugar. When you consume refined grains and sugars, your blood glucose spikes rapidly—giving you a temporary energy boost—only to crash soon after, leaving you more tired than before.

Research shows that substituting whole grains for refined ones improves fatigue scores. Why? Because whole grains provide:

• Fiber that slows digestion and releases energy gradually
• B vitamins essential for energy production
• More stable blood sugar levels throughout the day

Refined Grain Products to Limit

• White bread and pasta
• White rice
• Many baked goods and pastries
• Most commercial breakfast cereals

Liquid Energy Drainers

What you drink matters just as much as what you eat when it comes to maintaining energy.

Fruit Juices: Not As Healthy As You Think

While whole fruits can be energy-boosting nutritional powerhouses, their juiced counterparts might be doing more harm than good. Scientists consider fruit juice primarily as a source of sugar, which can increase health risks and contribute to those dreaded energy crashes.

The fiber removal during juicing means:

• Faster sugar absorption
• Potential blood sugar spikes followed by fatigue
• Missing out on the sustained energy benefits of whole fruits

Research suggests that whole fruits provide more sustained energy than their juiced versions, even though both contain beneficial nutrients.

Caffeine: The Double-Edged Sword

Here’s where things get interesting—and where your personal experience comes into play. Instead of boosting your energy, excessive caffeine can actually lead to:

When you consume too much caffeine, your brain’s adenosine receptors (the ones that help you feel sleepy) get blocked. Eventually, this creates a boomerang effect, potentially making your fatigue worse while simultaneously making it harder to get restful sleep.

The key is moderation. Research indicates that limiting caffeine intake can help avoid these negative consequences.

Portion Size and Meal Timing Matter

It’s not just what you eat—it’s how much and when.

Ever feel like taking a nap after a big meal? There’s science behind that food coma. When you eat large meals, your body diverts blood flow and energy to your digestive system, leaving less for other activities.

Studies show that eating several smaller, balanced meals throughout the day instead of fewer large ones helps maintain more consistent energy levels and prevents fatigue associated with major digestive efforts.

The Inflammatory Food Connection

Some foods trigger more inflammation than others, and this inflammatory response is directly tied to feelings of fatigue.

Red and Processed Meats

That juicy burger or bacon might taste great, but it could be contributing to your afternoon slump. Research from the Women’s Health Initiative study found that substituting fish for red and processed meat was associated with more favorable fatigue scores.

Why? Because these foods:

• Contain high amounts of saturated fat requiring more energy to digest
• Promote inflammation
• Often contain preservatives and additives that further exacerbate inflammatory responses

Hidden Food Sensitivities

Sometimes the foods making you tired aren’t the usual suspects. Undiagnosed food sensitivities can trigger inflammatory responses that manifest as fatigue.

Research on the “leaky gut diet” suggests that gluten and milk allergens might contribute to fatigue in some individuals through mechanisms related to intestinal barrier function.

If you’ve tried everything else and still feel chronically tired, it might be worth exploring potential food sensitivities with a healthcare provider.

Micronutrient Deficiencies: The Hidden Energy Thieves

Sometimes it’s not what you’re eating but what you’re missing that causes fatigue.

Several key nutrients directly impact your energy levels:

• Vitamin B12 (found in clams, dairy products, and eggs)
• Folic acid (abundant in dark leafy greens and citrus fruits)
• Iron (prevalent in lean meats, beans, and fortified cereals)

When these nutrients are insufficiently available, your body’s ability to produce energy at the cellular level is compromised, resulting in persistent fatigue.

Similarly, a diet lacking in antioxidant-rich foods may contribute to fatigue through increased oxidative stress. Studies comparing fatigued and non-fatigued individuals found that non-fatigued people had higher intakes of anti-inflammatory and anti-oxidative nutrients, including carotenoids, vitamin A, and vitamin C.

Staying Hydrated: An Often Overlooked Energy Factor

While we’ve focused on food, don’t forget that inadequate hydration can significantly impact your energy levels.

Sweetened beverages can cause blood sugar fluctuations similar to high-sugar foods, while alcohol has depressant effects that can leave you feeling drained.

Research suggests that water, black decaffeinated coffee, and unsweetened tea may be the best beverage options for preventing fatigue.

The Mediterranean Diet: A Blueprint for Sustained Energy

If you’re looking for a dietary pattern that promotes steady energy levels, the Mediterranean diet shows promise through its anti-inflammatory properties.

This dietary approach emphasizes:

• Whole grains
• Legumes
• Nuts
• Fish
• Lean meat
• Dairy
• Olive oil
• Fruits and vegetables

The beneficial effects of this diet are attributed to its high content of quality fatty acids, fibers, complex carbohydrates, vitamins, minerals, and plant compounds. In particular, olive oil is rich in oleic acid, which can be converted to compounds that inhibit inflammation.

Making Energy-Friendly Food Swaps

Instead of focusing on eliminating foods, try these simple swaps to boost your energy:

Instead of This	Try This
White bread	Whole grain bread
Fruit juice	Whole fruits
Large, heavy lunches	Smaller, balanced meals throughout the day
Processed meats	Fish, poultry, or plant-based proteins
Sugary snacks	Nuts, seeds, or fruit with yogurt
Multiple cups of coffee	Green tea or alternating with herbal tea

The Bottom Line

Your food choices have a direct impact on your energy levels throughout the day. While there’s no one-size-fits-all solution, the research consistently shows that whole, unprocessed foods rich in fiber, antioxidants, and healthy fats provide more sustained energy than their processed counterparts.

Paying attention to how different foods affect your personal energy levels can help you create an eating pattern that keeps you feeling your best all day long. Start with small changes, notice how you feel, and adjust accordingly.

Remember, the goal isn’t perfection—it’s discovering what works best for your body and lifestyle. Your most energetic self might be just a few food swaps away!