Some foods should be eaten raw to maximise your nutrient intake. But some others should be cooked for the same thing. Dietitian Susie Burrell provides a guide.
To eat raw or to eat cooked? That is the question…
When it comes to optimal nutrition there are several schools of thought in terms of whether it’s best to consume certain foods raw, or cooked. Vegetables in particular are often discussed along with seeds and nuts as nutritionally superior when consumed as part of a raw diet. Then there are the recommendations that suggest foods cooked in a certain way increase nutrient absorption while others are inhibited. So if you are looking to get the most out of your food, here is your own guide about what to eat raw and what to eat cooked to get the most out of your food on a daily basis.
As is the case with all areas of nutrition, it’s not as simple as ‘cooked vs. raw’. In fact much of the eating process right from the first bite you take impacts the way you digest and absorb the nutrients found in various types of food.
For example when it comes to raw vegetables and salad, chopping them helps to increase the availability of nutrients by breaking down relatively tough plant cell walls — think capsicum and cucumber skin. In a similar way, crushing and chopping some foods may help to release different enzymes as is the case with onions and garlic. Even soaking some foods — including beans — may help to reduce the acids that inhibit the absorption of some other nutrients.
Specifically when it comes to foods better consumed raw, it’s the nutrients effected by heat. Vitamins B and C, including folate, are all easily destroyed at high temperatures giving some rationale to consume foods rich in these nutrients — including leafy greens, capsicum, broccoli, avocado and cauliflower — raw. While these nutrients are heat sensitive, what is important to remember is that lightly heating the veggies is unlikely to be a major issue as opposed to cooking at high temperatures and in fact, serving salad vegetables or cooking these veggies with a little olive oil will actual increase nutrient absorption of other key nutrients. For this reason, there are benefits of eating a mix of raw and lightly cooked salad vegetables every day to tick all your nutritional boxes.
Then there are the nutrients that you’ll absorb more of when they’re cooked. While overcooking vegetables does tend to destroy certain vitamins (think soggy, discoloured vegetables boiled in a pot) cooking tomatoes and carrots for example actually increases the quantities of the antioxidants lycopene and beta carotene. This is the case for any red, orange and yellow vegetables for which lightly cooking will help to break down the cell walls and increase nutrient availability.
While vegetables and salad are the key foods targeted when it comes to raw vs. cooked, let’s not forget our proteins. Omega 3 fats found in oily fish are relatively stable raw or cooked but for any raw meat fans, or for those who like to add a raw egg or two to their morning shake, cooking these proteins helps to denature the proteins found in these foods, making them much more digestible.
10 foods to eat cooked
While we generally consume tomatoes raw in salads, heating tomatoes increases the lycopene content. Lycopene is a powerful antioxidant which helps to protect cells from damage and a high intake is associated with a reduction in the risk of developing prostate, lung and stomach cancers. Cooked tomatoes, tomato paste and sauces all offer the benefit of higher amounts of lycopene.
Raw eggs are a popular addition to shakes to boost the protein content, but cooking an egg helps to denature the protein, making it more readily digested and absorbed in the body.
Carrots are a rich source of the antioxidant beta carotene, which is converted to vitamin A in the body and which levels are significantly increased when the vegetable is heated.
Mushrooms have tough cell walls which means consuming them raw can leave them largely indigestible. The growing process may also leave some toxins on their flesh which will be destroyed when they are exposed to heat.
5. Red meat
Most of us enjoy our red meat cooked, but for anyone who may think raw is the way to go, if you’re after protein, heating the meat will again help to denature its protein making it more readily assimilated into the body.
Legumes (such as kidney beans and chic peas) have tough cell walls, which is the reason why soaking or lightly cooking them will help increase the nutrient availability of the bean. Soaking raw beans also helps to reduce the amount of phytic acid which can block the absorption of key nutrients including iron, zinc and calcium.
A light roasting helps to break down the tough cell wall of several nuts, including almonds. Helping with nutrient availability and absorption.
8. Prawns and shellfish
Shellfish are a rich source of a number of key nutrients including iodine, zinc and protein and applying some light heat will help to denature the protein found in animal foods, in turn helping with absorption.
A little heat applied to brown rice, quinoa and corn will help to breakdown their tough cell wall increasing the availability of key nutrients including vitamins B, magnesium, iron and zinc.
Cooking sweet potato at moderate temperatures helps to concentrate the beta carotene which is found in high amounts in bright orange and yellow veggies. Serve with extra virgin olive oil to also help maximise nutrient absorption.
10 foods to eat raw
The high nutrient content is identifiable from its bright colour, yet cooking antioxidant rich beetroot means it will lose more than 25% of its natural folate content. Folate is crucial for new cell generation in the body.
Olive oil is a rich source of vitamin E and antioxidants and while it can be used when cooking at low temperatures, the antioxidant content will be richest in the freshest extra virgin olive oil you can find.
You may not always reach for a bunch of broccoli to munch on, but more of the vitamin B5 found in it will be preserved when consumed raw. Heating broccoli also deactivates myrosinase, an enzyme that helps in the formation of sulforaphane, a molecule which has anti-cancer properties.
Consuming raw garlic has been shown to help reduce the risk of heart disease and some types of cancer but cooking it results in a loss of its potency. Chopping and crushing the garlic helps to release a nutrient called alliinase, a nutrient known for its anti-cancer properties.
5. Red capsicum
Packed full of the powerful antioxidant vitamin C, the nutrient content of brightly coloured capsicums will be destroyed when exposed to high temperatures. For this reason a red capsicum makes the perfect nutrient rich, low calorie snack during the day.
Another antioxidant rich superfood, berries are rich in vitamin C, some of which will be destroyed when heated. As such, berries make a great snack, or addition to yoghurt or smoothies.
Key B group vitamins and vitamin C are found in high quantities in leafy greens, nutrients which are easily destroyed when heated. For this reason they’re best consumed raw, without over exposure to heat via cooking and blending.
Seeds (such as pumpkin and sunflower seeds) are a rich source of vitamin B1 or thiamin which are easily destroyed when exposed to heat. Seeds are best enjoyed raw as part of a snack such as in trail mix.
Like spinach, the nutrients found in kale are easily destroyed by heat. Where possible, consume raw or exposed to light heat.
A number of nutrients including vitamin B as well as antioxidants run the risk of being destroyed when cauliflower is cooked. For some people, the fibres in cauliflower may result in excessive gas so be careful if you are sensitive to bloating.
Susie Burrell is one of Australia’s leading dietitians and a regular on Australia’s TV and radio. Get in touch at susieburrell.com.au.