by Alejandra "Alex" Ruani — Get free science updates here.
There are many benefits to consuming raw vegetables, which give you plenty of micro-nutrients and antioxidants.
In contrast, deep frying destroys antioxidants and also poses a risk to your health: oils heated at high temperatures release free radicals, which can injure cells and DNA in your body.
Now, does this mean that we should eat only raw food and exclude cooked food all together?
Cooking is crucial to our health and raw vegetables are not always more nutritious.
To cook or not to cook
Let’s take the example of tomatoes.
Cornell University researcher Rui Hai Liu found that lycopene levels rose 35% after cooking tomatoes for 30 minutes at 88 degrees Celcius.
Cooking vegetables also seems to have a positive effect on some antioxidants by increasing their bioavailability, particularly carotenoids found in carrots, cabbage, bell peppers, spinach, kale and asparagus.
On the other hand, studies show some veggies, including broccoli, retain more glucosinolate (a DNA-protective phytochemical) when raw or lightly steamed.
The query of raw or cooked food does not have a straightforward answer, as you’ll see.
So which option grants more nutrients?
Raw foodists contend that enzymes in raw foods enhance digestion and fight many chronic diseases. However, science isn’t so definitive on eating a diet entirely based on uncooked foods.
When it comes to cooking and nutrient retention, four of the biggest factors are that it largely depends on:
- the actual food (e.g. carrots)
- the length of cooking time (e.g. 15 minutes)
- the cooking method (e.g. boiling)
- the nutrient analysed (e.g. beta-carotene)
Let’s break it down and give you the facts. You’ll then have a clearer picture on which to make a decision.
Cooked food considerations
As we said, two of the biggest determinants of which is better rests on how you cook the food, and for how long.
Heat can break down and destroy 15-20% of some vitamins in vegetables – especially vitamin C, folate, and potassium.
The influence of cooking on antioxidant activity evaluated in 20 vegetables has shown that pressure-cooking and boiling lead to the greatest losses. What produced the lowest losses? Griddling, microwaving and baking.
In another study done on the health-promoting compounds of broccoli, all cooking treatments, except steaming, caused great losses of chlorophyll and vitamin C. Only boiling and stir-frying caused the loss of total carotenoids.
You also need to consider which specific nutrients you want to get more of. For instance, boiling carrots increases their carotenoid levels. However, they completely lose their polyphenols after boiling. So, if it’s the polyphenols that you’re after (rather than the carotenoids), you’re better off eating them raw.
Raw food reviews
It is said that raw vegetables are a ‘live food’. In other words, they contain life energy. Virtually all living things emit particles of light known as biophotons or ‘sun energy’, which contribute to the idea of live food. It’s worth a mention; however, since this is impossible to find in science-based published findings, we’ll leave it at that.
Here are three facts that we note to acknowledge that plant-based diet components, whether you eat them raw or cooked, can provide protection and reduction of certain health issues:
- Eating vegetables (raw or cooked) provide us with fibre, which absorbs bile acids and cholesterol. This reduces the risk of developing heart issues.
- Health benefits of vegetables also include disease-fighting phytochemicals, maintenance of bowel health, and in people with diabetes, fibre can help slow the absorption of sugar and help improve blood sugar levels.
- Enhancing your diet with plant foods can lower the risk of developing certain cancers.
Expand your nutrient density and diversity
It is a challenge to present one definitive answer to the enquiry of cooked versus raw. There are many, many variables that do not provide an apples-to-apples comparison, if you will.
As a matter of fact, one of the major studies guides us to recognise that none set out to directly compare the effects of the same vegetables eaten in their raw versus cooked state.
One common thread in quite a few of the publications and studies included this recommendation:
The public should be encouraged to increase their vegetable intake and to consider eating some of them raw.
It might be a wise choice to expand our micro-nutrient density, absorption of plant protein, and our nutrient diversity by including conservatively cooked food in our diet.
A general conclusion from a majority of the studies? The best vegetables will be the ones that you eat!
How about you? Have you you found success with either raw or cooked food? Or do you include a blend of both cooked and raw in your diet?
Let us know in the comments below! And if you know someone who is confused by the raw or cooked food dilemma, please share this with them!
Alex Ruani leads the research division at The Health Sciences Academy, where she and her team make sense of complex scientific literature and translate it into easy-to-understand practical concepts for students. She is a Harvard-trained scientific researcher who specialises in cravings and appetite neurobiology, nutrition biochemistry, and nutrigenomics. Besides investigating and teaching the latest advances in health and nutrition science, Alex makes it easier to be smarter with her free Science Catch-ups every other Thursday.