How to Roast Vegetables Without Oil (WFPB)

In this post I’ll share how to roast vegetables without oil so that they’re still just as scrumptious as you’d expect from the roasted vegetables you’ve always eaten.

Except I think they’re even more delicious.

Less oil, more healthy, fewer calories.

Why Roast Vegetables Without Oil?

The discovery and development of eating a whole foods plant based diet for top health was was founded by Dr. Colin Campbell a physician who reversed many cases of diabetes and heart disease by changing the diet of the patients.

A whole foods plant based diet revolves around eating only health-promoting foods and removing processed foods, including oil, from the diet.

At the very least, eating oil-free roasted vegetables is a low calorie, healthier choice than eating oil-roasted veggies, but the question is, can they be as appetising?

Intro to How to Roast Vegetables Without Oil

I’ve been experimenting with how to roast vegetables without oil and in this post I’m going to share what I think is the tastiest way to convert to oil free roasted vegetables.

They’ll taste slightly different to oil roasted vegetables, and that’s just something you’ll need to accept as a given. The secret is, there’s nothing better about traditional roast vegetables.

Nothing at all.

It’s all a matter of habit.

Once you adapt to the new flavours, you’ll be looking forward to oil free roasted vegetables just as much, or more, than you used to before.

When you start to get into a whole foods plant based way of eating, you quickly realise that oil is the most calorie-dense food we eat – and it doesn’t contribute significantly with nutrition or health.

In fact, as we all know, fried food is the least healthy way to eat.

You may like to read a simple guide to a wfpb diet to understand the far-reaching health benefits of adopting a plant based, oil free way of life.

Which Vegetables to Roast Vegetables without Oil

You can actually roast any vegetable that you have in your cupboard or fridge, oil free. The results will vary depending on the veggie and it’s a personal choice thing, which ones you think taste the best.

For me, potatoes are the least rewarding of vegetables to roast without oil in the oven, but maybe that’s because I don’t eat a lot of potatoes anyway, and when I do, it will normally be a jacket potato or potatoes in the air fryer.

Otherwise I use sweet potatoes. I think they’re more delicious!

In the past, I admit I used to love to occasionally eat a pile of roasted potatoes in olive oil and salt and potato is the one vegetable that seems dry when roasted without the oil. Perhaps the best solution is to keep potatoes for very special occasions and sub for sweet potatoes without the oil.

How to Roast Vegetables without Oil: Vegetables that Roast Well

  • sweet potato – my favourite!
  • zucchini
  • carrots
  • purple cabbage
  • green cabbage
  • eggplant
  • bell peppers
  • mushrooms
  • onion (not my favourite oil free vegetable to roast)
  • roasted cauliflower recipe

Non-Vegetable Ingredients to Roast with the Vegetables without Oil

  • tofu
  • chickpeas
  • spices on the vegetables for variation

How to Roast Vegetables Without Oil But with All the Flavour

How to roast vegetables without oil. Red pepper, tofu and carrot on a fork

When you first come across the wfpb diet, or whole foods plant based diet, and you wonder how to roast vegetables without oil without losing the flavour, you might assume it’s going to be difficult.

But it isn’t.

I think psychologically it’s more challenging than in actual fact. We’re so used to thinking that everything gets cooked in oil.

And I know, because I used to love my olive oil for cooking.

How to Roast Vegetables without Oil – Oil Substitutes

Although I recommend the method described in this post the most, there are other options too. The most common liquids which people use for roasting oil-free vegetables are:

  • nothing – since writing this post I’ve adopted the habit of dry roasting vegetables without any added liquid and I love it
  • water – the most obvious and easy liquid
  • lemon juice – the star of this post and my absolute favourite choice
  • orange juice – not my favourite, I don’t like this one
  • lime juice – I prefer lemon juice
  • apple compote – neutral results
  • balsamic vinegar – hmm
  • vegetable stock – same as water IMO

In this post we’ll be looking specifically at roasting in lemon juice.

Different people use different liquids to roast vegetables without oil, but in my opinion, lemon juice with lemon zest is the best way, because it creates the most delicious results.

How to Roast Vegetables without Oil in Lemon Juice & Lemon Zest

By far my favourite method of roasting vegetables without oil is to squeeze some lemon juice over the vegetables and stir to mix. Sprinkle with a little salt and grate some zest (skin) of the lemon onto the vegetables.

You can omit the salt if you’re salt free.

Preparing the Vegetables for Roasting

Some things are a matter of practise and one of those is the ability to chop the vegetables so that they cook in roughly the same time as each other.

You’ll want to wash and trim off any bad bits, then chop the vegetable to the size you want. With cabbage, it’s important to leave it in larger, solid chunks so that it retains its yummy juiciness and doesn’t dry out.

For roasting zucchini, I like to slice it down the middle lengthwise, then in half again and roast it in half boats.

For the rest of the veggies, chop them into large bite sized pieces and place in a baking tray.

Place the baking tray into the oven and roast for approx 30 minutes, checking half way through and stirring to stop the veggies from burning on the top.

How to roast vegetables without oil. Vegetables ina baking pan with lemon zest

How Much Lemon Juice & Zest to Use

It will depend on how many vegetables you’re roasting and how big the lemon! But the great thing about using lemon juice for roasting is that you can add just a little squeeze and then add more as necessary during the cooking process.

The lemon zest really takes this dish to the next level. On average I would use the zest from about half a lemon, but when you’ve done it a few times you’ll discover how you like it best.

I also like to add chickpeas and tofu to the pan of roasted vegetables.

How to Roast Vegetables without Oil, Using Water

You can use water instead of lemon juice by sprinkling a little water over the veggies before baking in the oven.

You need to keep an eye on the vegetables to make sure that they don’t try out and stick to the pan as the water evaporates. Add another sprinkle when necessary, rather than adding too much in one go.

If you put a lot of water in the pan at the start, the vegetables will cook in the water and steam, so they will be more like steamed vegetables rather than roast, and they won’t caramelise.

Veggies roasted in water don’t have the same panache as lemon roasted vegetables in my opinion.

And I don’t really like the results of roasting in water.

How to Roast Vegetables without Oil: Troubleshooting

Of course as with any switch over, it may take practise before roasting without oil becomes second nature to you. And you may have a few times when the vegetables don’t come out how you want them.

Don’t give up!

Once you cross the line into oil free roasting with success, it no longer holds any hazards or risks. It just becomes plain old easy. Like any roasting.

Potential Problems When First Roasting Vegetables Without Oil

Some of the things that may happen when you first start roasting without oil.

The vegetables might . . .

  • . . . stick to the bottom of the pan.
  • . . . be too dry
  • . . . lack flavour
  • . . . be soft and not caramelised
  • . . . not be cooked through
  • . . . be cooked unevenly (some are cooked, others still half raw)

Solutions for Problems When First Roasting Vegetables Without Oil

  • Vegetables sticking to the bottom of the pan: some sticking will occur and isn’t a problem, but to avoid overly sticking, using lemon juice seems more effective than water or other liquids. You can also use baking paper to line the baking tray.
  • Dry vegetables: some types of veggies will become naturally too dry if you don’t squeeze on enough lemon juice, but don’t worry, you can use a little in the beginning and then squeeze on more half way through cooking if you see that the veggies are drying out.
  • Lacking flavour: a lack of flavour can be true if you roast the vegetables in water, but when you use lemon juice and the zest, the flavour really pops. You can, if you want some variation, add some spices to the vegetables, but they are completely flavoursome without.
  • Soft Vegetables Instead of Crunchy Roasted Veggies: too much water can make the veggies soggy instead of caramelised.
  • Hard vegetables: If the veggies aren’t cooked through, you may not have enough liquid in the pan.
  • Unevenly cooked: when you find some veggies are fully cooked and others are still half raw, it’s a problem with the chopping. Adapt the size of the chunks you roast, so that they all roast together. In the meantime, you may have to let some veggies over-cook to get the other ones cooked through.

How to Serve Oil-Free Roasted Vegetables

Serve these scrumptious veggies on the side or as a complete meal.

Separate the vegetables and make some oil free roasted sweet potato (or potato if you prefer) to accompany a main course.

Alternatively, do a great big veggie mix along with tofu and chickpeas and serve as a complete meal.

Serve as part of a buddha bowl or as the main meal with a gram flour flatbread alongside.

Delicious Complete Meal of Vegetables Roasted Without Oil

By adding some chickpeas and tofu to the pan you ‘ll be adding a protein source to complete the meal.

Chop the veggies into large bite sized chunks and place in a baking tray along with some chickpeas. Squeeze over with lemon juice and lemon zest and put in the oven at 200º for 30 minutes.

After 15 minutes, use a spatula to turn the veggies and test how cooked they are. It should take approx 30-40 minutes for them to be soft and ready to eat.

Deliciously roasted.

Add extra cumin at the start of cooking for variation and serve with some nutritional yeast and fresh cilantro sauce.

How to Roast Vegetables Without Oil

Recipe by SorayaCourse: Main course, LunchCuisine: WFP, Oil Free, Vegan, Gluten Free


Prep time


Cooking time



Wonderful simple recipe for a delicious meal


  • For The Vegetables (All optional)
  • 4 carrots, cut into rounds

  • 1 eggplant cut into rounds, then quartered

  • 2 zucchinis, cut in half

  • 1 large red pepper, chopped into large pieces

  • 4 large mushrooms, quartered

  • 1/4 red cabbage, chopped into chunky chunks

  • For the Protein
  • 1 packet hard tofu

  • 1 jar chickpeas


  • Wash the vegetables and chop them into large bite sized pieces, except the zucchini which you can cut in half.
  • Grate 1/2 the skin of 1 lemon over the vegetables.
  • Cut the lemon in half and squeeze on the juice from half a lemon.
  • Sprinkle with salt if using.
  • Place in a pre-heated oven at 200ºc.
  • After 15 minutes, turn the vegetables over.
  • At 30 minutes check to see if the veggies are cooked.


  • Once you’ve discovered how to roast vegetables without oil and without loss of flavour, you won’t got back to roasting with oil.

General Vegan Cooking Without Oil

Vegan cooking without oil is simpler than cooking with oil. You just cook the vegetables straight into the pan or with a little water or lemon juice.

Oil free cooking in an air fryer is an example of how easy this way of eating can be.

There’s no oily mess to clean up and you know that the food you’re eating is as healthy as can be. After eating this way for a little while, you may well find yourself wondering why you would ever want to add oil to a pan again.

It’s all about re-educating the mind and managing expectations. When we expect something specific, then any variation on that expectation can be construed as a disappointment, when really it’s just misplaced expectations.

How to Cook Without Oil

Steaming Vegetables

Steaming vegetables is the process of cooking them in their steam.

You can buy a steamer for this, or you can steam the veggies in a normal pan by using a small amount of water in the bottom and a tightly fitting lid.

The veggies are partially in the water, but only a little. The most part of the vegetables is above water, being cooked by the steam.

Frying Without Oil

When frying without oil, use a hot, dry pan to begin with.

Add the vegetables and fry until they release a little moisture and the process continues. If they are too dry, add a tiny amount of water just moisten the bottom of the pan – if and when necessary.

It’s important not to add too much liquid or you won’t get the fried effect.

When you fry without oil, you may get a build up of caramelisation on the base of the pan. You can use a wooden spoon to scrape it off and incorporate into the food.

This process is called ‘de-glazing’ which sounds much more sophisticated than scraping the bottom of a pan with a wooden spoon!

You can also use lemon juice for frying, but it isn’t necessary and can be used as an optional alternative as water works just fine.

Oil Free Soups

To make oil free soups you can either roast the vegetables without oil first or fry them in a little water. For roasting the vegetables for a soup, they can be roasted dry and covered with silver foil to keep in the moisture.

This won’t produce the ‘roasted’ flavour but can work well for soups.

Once you have your base ingredient/s roasted, add a delicious homemade vegan stock to the base of the soup and mix, or blend, depending on the desired result.

Some great oil free soup recipes are:

How to make oil free roasted vegetables - a mix on a plate

Quick Version of Roasted Vegetables without Oil

To make this recipe in under 30 minutes, simply chop the vegetables smaller so that they cook quicker.

I hope you enjoyed this post and the results in your cooking!

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