7 signs you’re doing veganism wrong (and why you still feel tired all the time)

Let’s be honest—nobody goes vegan hoping to feel worse.

You make the switch with the best intentions. You want to feel lighter, healthier, maybe even more energized. But instead? You’re constantly dragging. Your eyelids are heavy by 3pm. Your workouts feel harder than they should. And you’ve quietly started wondering if you’re just not cut out for this plant-based life.

But here’s the thing: feeling tired all the time on a vegan diet isn’t inevitable—it’s usually a sign something’s off.

In fact, after talking with other long-time vegans and diving into research, I’ve realized there are a few surprisingly common pitfalls that can sneak into even the most well-meaning plant-based routines.

If you’ve been asking yourself, “Why am I still so tired?” these seven signs might be worth exploring.

1. You’re not eating enough (especially calories)

Let’s start with the most overlooked reason: not eating enough.

Plant-based foods are often less calorie-dense than their animal-based counterparts. That salad with lentils, quinoa, and veggies might be packed with nutrients—but it may not give you the same sustained energy as the steak and potatoes you used to eat.

I made this mistake early on. I’d eat the same portion sizes as before, but by late afternoon, I’d be shaky, irritable, and in desperate need of a nap. Turns out, I was running on a calorie deficit without realizing it.

If you’re feeling constantly fatigued, it might be time to track your intake—not forever, just for a few days. You might be surprised how far under your energy needs you’re falling.

2. You’re missing out on vitamin B12

This one’s a biggie.

Vitamin B12 is essential for energy, brain function, and red blood cell formation. But here’s the catch—it’s not found naturally in plant foods. If you’re not supplementing or eating fortified foods, you’re probably running low.

As noted by registered dietitian Taylor Wolfram, “B12 deficiency is one of the most common—and preventable—nutritional issues among vegans. It can cause fatigue, weakness, and even neurological symptoms if left unaddressed.”

Don’t wait until you’re exhausted to act. B12 is cheap, easy to supplement, and absolutely necessary.

3. You’ve replaced meat with carbs—but not much else

Let’s say you used to have chicken with rice and veggies. Now you’ve ditched the chicken, added more rice, maybe an avocado—and called it dinner.

The problem? You’ve traded protein for more starch. And while carbs are important, they’re not a one-for-one substitute.

Your body needs protein to build muscle, repair tissue, and regulate hormones. Without enough of it, fatigue becomes a constant background noise.

The good news: there are plenty of plant-based protein sources. Think lentils, tofu, tempeh, seitan, chickpeas, edamame, and protein-rich grains like quinoa. Sprinkle in nuts and seeds, too. Variety matters.

I had to relearn how to build a plate. Now, instead of asking “What’s for dinner?” I ask, “Where’s the protein?” It makes a difference.

4. You’re stuck in a beige food loop

Ever notice how many convenient vegan foods are beige? Crackers. Hummus. Pasta. Cereal. Bread. Oat milk. Granola bars.

They’re comforting, easy, and yes—technically plant-based. But when your plate looks like a washed-out color swatch, you’re probably missing out on key nutrients like iron, magnesium, potassium, and zinc.

Brightly colored whole foods—spinach, red peppers, purple cabbage, berries, oranges, sweet potatoes—are bursting with the micronutrients your energy systems rely on.

Experts often call this “eating the rainbow” for a reason. It’s not just pretty—it’s powerful.

If your meals have been looking a little too neutral lately, try adding more color. Your energy will thank you.

5. You’re ignoring iron (or pairing it wrong)

Iron is essential for oxygen transport in the blood. Without enough of it, you can feel exhausted, foggy, and short of breath—even if you’re getting enough sleep.

Now here’s the vegan-specific twist: plant-based iron (non-heme iron) isn’t absorbed as easily as the iron found in animal products. And to make matters worse, some common pairings actually block absorption.

Example? Eating iron-rich beans with a calcium-rich food like fortified almond milk or tofu can reduce how much iron you absorb. So can tea and coffee if consumed around meals.

But pair iron with vitamin C—like lentils with bell peppers, or spinach with lemon juice—and you boost your absorption significantly.

As noted by the National Institutes of Health, “Vitamin C can enhance non-heme iron absorption up to sixfold when consumed in the same meal.” Small tweaks like this can help keep your energy up without changing your entire diet.

6. You’re not paying attention to omega-3s

Fat often gets a bad rap in wellness circles, but it’s critical for brain health, hormone balance, and yes—sustained energy.

If you’ve cut out fish but haven’t replaced those omega-3 fats with plant sources, your body might be struggling more than you think.

Flaxseeds, chia seeds, hemp seeds, and walnuts are great vegan-friendly options. Algae oil supplements are another easy solution, especially for those who want the long-chain omega-3s (DHA and EPA) typically found in fish.

When I added a tablespoon of ground flax to my morning smoothie, I didn’t expect much. But over a few weeks, I noticed better focus—and slightly less afternoon brain fog.

It wasn’t magic. It was maintenance.

7. You’ve gone “plant-based” but not “whole-foods based”

It’s tempting to lean on plant-based burgers, vegan pizza, frozen meals, and sweetened oat milk when you’re busy. And I get it. Convenience matters.

But a vegan diet that’s heavy on processed foods can still leave you feeling drained. You might be technically vegan, but not necessarily nourished.

I had a stretch where my freezer was full of microwaveable vegan burritos and dairy-free ice cream. It was easy. But I was bloated, cranky, and always tired. Once I got back to basics—whole grains, legumes, fresh produce, nuts and seeds—my body felt like it exhaled.

Veganism isn’t just about what you don’t eat. It’s also about what you do eat. The closer your food is to its original form, the more likely it is to give you sustained energy.

Final thoughts

If you’ve been feeling tired all the time on a vegan diet, it’s not a personal failure—and it doesn’t mean you need to quit.

It probably means your approach needs a tune-up.

Try taking a curious, gentle look at your habits. Where are you skimping? What’s missing? What might need rethinking?

Veganism, when done thoughtfully, can be energizing, sustainable, and incredibly nourishing. But like any diet, it needs attention, variety, and balance.

Your energy levels aren’t just random—they’re feedback. Listen to what your body’s telling you.

And give yourself permission to adjust as you go.