30 Days of OMAD on a Vegan Diet: My Surprising Journey and Results

Spoiler: I did not become a productivity cyborg.

But I did learn a lot—about hunger, habits, and how quickly spinach wilts when you’re trying to cram a full day’s nutrition into one sitting.

For context, I’m a data-minded vegan who likes to experiment with food systems, both on a macro (climate) and micro (my own kitchen) level.

So when a friend offhandedly mentioned they’d been doing OMAD—aka “One Meal A Day”—to simplify their life and cut down food costs, my curiosity kicked in.

Could a plant-based OMAD regimen work? Would it boost focus? Make grocery shopping easier? Or just turn me into a hangry kale monster by day 12?

I committed to 30 days, notebook in hand. Here’s what actually happened.

Wait, what is OMAD, and why do people do it?

OMAD is a form of intermittent fasting where you consume all your daily calories in a single meal, typically within a one-hour eating window. The rest of the day? Water, tea, maybe black coffee. That’s it.

Proponents say it sharpens mental clarity, supports weight loss, saves time, and reduces decision fatigue.

But here’s the kicker: most of the buzzy OMAD content online centers around high-protein, animal-heavy diets. Steak. Eggs. Whey shakes.

Very little guidance exists for those of us who want to hit our nutritional goals without animal products—or ultra-processed vegan snacks.

So I set out to test the plant-based OMAD hypothesis. Would it actually help or hinder my physical, emotional, and cognitive well-being?

Setting the rules: How I structured the 30 days

I decided early on that this wouldn’t be a crash diet. My aim was not to lose weight or biohack my way into some Silicon Valley dopamine utopia.

It was to explore how a structured meal schedule could impact my life—and whether it was even possible to get full nutrition on a once-a-day vegan plan.

Here’s what I locked in:

• One eating window per day: 5:30–6:30PM

• Minimum calories per meal: 1,800–2,200

• Macronutrient balance: ~50% carbs, 25% protein, 25% fats

• Whole foods focus: No protein bars, minimal packaged snacks

• Hydration: Herbal teas and lots of water throughout the day

• Supplements: B12, Vitamin D, Omega-3 algae oil

Every Sunday, I prepped large-batch grains (quinoa, wild rice), roasted trays of vegetables, soaked legumes, and made sauce bases (think tahini-garlic, coconut curry, chimichurri) to keep things interesting.

Week 1: Hunger games and surprise energy

I expected to feel miserable by day three. Oddly, I didn’t.

Yes, I got hungry—especially in the mornings. But I also noticed a surprising steadiness in my energy levels. No mid-afternoon slump. No decision fatigue from wondering “what’s for lunch?”

There’s a theory here. A 2022 study found that time-restricted eating (like OMAD) may improve insulin sensitivity and support better metabolic regulation—even without weight loss. My data-backed brain loved this.

But let’s be real: the biggest hurdle was meal volume. Imagine trying to eat 2,000 calories of lentils, leafy greens, sweet potatoes, avocado, nuts, and tofu in one sitting without feeling like a human compost bin.

It was a digestive adventure.

Week 2: Mood swings, meal envy, and the social struggle

If week one was curiosity-fueled, week two got… complicated.

I started to crave warm lunches—not because I was hungry, but because I missed the ritual. The social cue. The smell of reheating leftovers in a shared office kitchen.

Plus, the “one big meal” started to feel like a chore. Cooking it. Eating it. Digesting it. Then doing nothing food-related for another 23 hours? It threw off my rhythm.

And let’s not ignore the mood swings. My partner joked that I entered a new personality tier around 4PM. It wasn’t wrong. I was shorter-tempered, less patient, and slightly more obsessed with food videos than usual.

Was it low blood sugar? Possibly. But I also suspect it was the mental strain of resisting all-day food culture—work meetings over matcha, weekend brunches, the casual joy of grazing.

Week 3: Better digestion, clearer skin, sharper focus

Right around day 17, I hit a sweet spot.

My digestion, which usually flares up from stress-snacking and hasty meals, was calm. My skin looked better. I wasn’t bloated. I wasn’t obsessing over snacks. I started to feel…clear.

And my food tasted incredible. When you eat just one meal a day, you learn to make it count.

I got creative: jackfruit tacos with pickled red onions, miso-glazed eggplant over rice noodles, a peanut-lime tempeh bowl topped with mango salsa.

More interestingly, I started sleeping better. Studies support this: time-restricted eating can improve sleep efficiency and even support melatonin production.

Still, I wasn’t ready to call it a miracle. I missed the simple pleasure of a cozy breakfast or impromptu afternoon smoothie.

Week 4: The emotional curveball

By the final week, I realized something: I wasn’t emotionally satiated.

Physically? I was doing fine. My energy stayed consistent, my workouts didn’t suffer, and I felt like a kitchen ninja balancing flavor and function.

But emotionally, I missed the communal aspect of eating.

Food is more than fuel. It’s comfort. It’s connection. It’s memory.

I missed testing a new soup recipe at lunch. Missed drinking tea with oat milk in the mornings. Missed nibbling vegan chocolate while watching a movie. I didn’t need those things nutritionally, but emotionally? They mattered.

And that’s where OMAD fell short for me. It reduced food to a singular event—and I craved the multi-dimensionality of it all.

What I learned (and what I’ll take forward)

Would I recommend OMAD on a vegan diet?

Yes—with some serious caveats.

If you’re looking for a temporary reset, or a way to understand your eating patterns more clearly, OMAD can be a useful experiment.

But if you’re someone who thrives on shared meals, food rituals, or mid-day nourishment, it may feel isolating long-term.

Here’s what I’m keeping:

• Mindful meal prep: Planning one thoughtful meal a day made me more intentional about flavor, texture, and nutrition.

• Reduced snacking: I broke the habit of mindless munching. Now I snack with purpose.

• Evening feasts: I genuinely love sitting down to a colorful, nutrient-dense bowl without distractions. That’s staying.

Here’s what I’m letting go:

• Rigid fasting: I’m moving to a more flexible intermittent fasting rhythm—likely a 16:8 model (eating between 11AM–7PM).

• All-or-nothing mentality: Food is connection. I want to eat lunch with friends. I want to test vegan cookies at 2PM. That’s okay.

The bigger “why”: Food systems, simplicity, and sustainability

Stepping back, OMAD taught me more than just how to steam broccoli five different ways.

It reminded me that our relationship with food is complex—and deeply personal. And that sustainability doesn’t always mean consuming less; sometimes it means consuming more consciously.

A plant-based OMAD diet is certainly more planet-friendly than an omnivorous one. Eating less frequently, cooking at home, and minimizing waste all reinforce that climate-conscious loop.

But for me, the biggest win was clarity.

Clarity about how much I was eating. About what my body actually needed. About which food rituals served me—and which ones were just habits in disguise.

That kind of awareness? It’s worth every chickpea.

Final verdict: Should you try OMAD on a vegan diet?

If you’re curious and grounded in your “why,” go for it.

But don’t do it because it’s trendy. Or because someone on TikTok swears it gave them superpowers. Do it because you want to learn about your rhythms, your body, your food triggers.

Just remember: veganism is already a powerful act of intention. You don’t need to layer on extreme eating windows to “optimize” it.

As always, listen to your body. Listen to your hunger. And if your intuition says, “Hey, I miss breakfast,” that’s valid.

Trust me—I did too.