The Science of Eating: Raw vs. Cooked

Updated: May 08, 2024Veronika Larisova

Food's role in human evolution, culture, and health is undeniably pivotal. Historically, the debate around raw versus cooked food consumption has evolved in tandem with scientific understanding. The distinction, however, isn't merely binary. Different foods necessitate varied approaches: while some, like potatoes and legumes, require cooking for safe consumption, others, such as many vegetables, retain maximum nutritional value when consumed raw or minimally processed. From a biochemical standpoint, cooking facilitates various reactions, enhancing digestibility, flavour, and texture and introducing beneficial compounds like resistant starches in cooled cooked potatoes. Conversely, high-temperature cooking, especially with seed oils, can generate potentially harmful compounds and degrade essential vitamins and enzymes. Given these complexities, our focus should shift from generalised advice to a nuanced understanding of optimising nutritional benefits through selective cooking practices.

In summary, cooking can improve food safety, digestibility, and taste, but it can also lead to the loss of certain nutrients and the formation of potentially harmful compounds. A balanced diet combines raw, cooked and fermented foods to provide various nutrients and flavours.

Diving into the culinary world, what stacks up in the showdown between cooked and raw foods? Let's unravel this tasty debate!

RAW FOOD

PROS:

Enzymes Preservation

Raw foods contain natural enzymes, which assist digestion by breaking down nutrients and facilitating better absorption. Such foods should be eaten raw as heat deactivates these enzymes. Examples include papaya, pineapple, garlic, onion, and zucchini.

Nutrient Retention

Raw foods, untouched by the heat and processes of cooking, often retain their full spectrum of vitamins and minerals, particularly those that are heat sensitive. For instance, water-soluble vitamins such as vitamin C and certain B vitamins are preserved at their natural concentrations in raw foods. Moreover, the phytochemicals and antioxidants in raw fruits and vegetables, essential for combating oxidative stress, are maintained in their entirety. Consuming raw foods ensures that the nutrient profile remains unaltered.

No Harmful By-products

Cooking, especially at high temperatures, can produce harmful compounds. Consuming foods like raw berries or salads bypasses the risks these by-products pose.

CONS:

Potential for Pathogens

Raw foods, especially meats like sushi or steak tartare, can harbour harmful bacteria and parasites. Cooking effectively kills these pathogens, reducing the risk of foodborne illnesses.

Digestive Challenges

Some foods, like cruciferous vegetables (broccoli or cauliflower), can be harder to digest when raw. Cooking softens these foods, making them easier on the stomach. We recommend eating these foods lightly steamed to improve digestibility while preserving most nutrients.

Presence of Antinutrients

Antinutrients are compounds found naturally in many foods, especially in plants. They can interfere with the absorption or digestion of nutrients. Some examples include lectins in beans, phytic acid in legumes and grains, and oxalates in spinach. These foods should always be eaten cooked. Beans, legumes, and grains should be soaked first.

COOKED FOOD

PROS:

Enhanced Nutrient Availability

Cooking can improve the bioavailability of certain nutrients. For example, while raw carrots are nutritious, cooking them boosts their beta-carotene content, which our bodies convert to vitamin A.

Improved Digestibility

Cooking processes like boiling or roasting break down plant cell walls in foods like potatoes, releasing nutrients and making them easier to absorb.

Resistant Starch Alteration

Cooking and cooling foods like potatoes or rice transforms some starches into "resistant starches". These starches resist digestion, reaching the large intestine and serving as food for beneficial gut bacteria.

Flavourful Transformations

The Maillard reaction, responsible for the browned, complex flavours of seared steaks or toasted bread, enhances the taste profile of many foods. While this is a PRO regarding the enjoyment factor, it’s a CON regarding health, as the Milliard reaction releases harmful AGEs.

CONS:

Loss of Certain Nutrients

Cooking can degrade certain nutrients. Vegetables, for instance, lose some of their vitamin C content when cooked. Other vitamins and minerals impacted by heat are A, B, polyphenols, potassium, magnesium, zinc and glucosinolates. Light steaming is the best option for most vegetables.

Formation of Harmful Compounds

Cooking at high temperatures, especially in unstable seed oils like sunflower or corn oil, can form toxic and inflammatory compounds such as Advanced Glycation End-products (AGEs). These compounds have been linked to numerous health issues, including inflammation and cancer. Avoid grilling, charring and reheating seed and vegetable oils. Using acidic substances like lime juice while cooking/frying may be useful in reducing the AGEs content.

SPECIAL MENTIONS

Cooking Oils

It's important to choose the right oils for cooking. Cooking in seed oils can produce AGEs, which can be harmful. Reheating seed oils is highly inflammatory and should be avoided at any cost. Oils with high smoke points, like avocado or coconut oil, are better for high-temperature cooking.

Air-Dried Meats

Techniques like air-drying meats, as seen in biltong, preserve the food and concentrate flavours. These methods often increase protein density, providing a nutrient-rich snack with a lower risk of pathogens found in raw meats.

Inbetweeners: FERMENTED FOODS

Fermented foods introduce an intriguing twist in the raw vs. cooked debate. While they aren't traditionally "cooked" using heat, they aren't entirely "raw" in the standard sense. Instead, they've been transformed by beneficial microorganisms, making them a unique category worth exploring.

Like cooking, fermentation can increase the bioavailability of certain nutrients. This natural preservation process can enhance levels of B vitamins, especially folic acid and riboflavin. Additionally, fermented foods can be a good source of probiotics, essential for gut health. Scientific research indicates that daily consumption of fermented foods is the best tool for increasing gut microbiota diversity. Yes, better than taking probiotic supplements or consuming lots of fibre!!! Fermentation also can break down food components that some people find hard to digest. For example, lactose in milk is broken down into simpler sugars during fermentation, making products like yogurt and kefir more digestible for lactose intolerant. While cooking kills off bacteria through heat, fermentation controls the food environment, promoting the growth of beneficial bacteria and suppressing harmful ones. Furthermore, fermentation can reduce antinutrients, compounds that can interfere with the absorption of essential nutrients. Phytic acid, for instance, which can inhibit the absorption of certain minerals, is broken down during the fermentation of grains and legumes.

Chief favourite fermented foods: sauerkraut, kimchi, kefir, and miso. We also love a good kombucha.

So, what’s the verdict? Raw or cooked?

Both raw and cooked foods have their rightful places on our plates. Incorporating a mix, like pairing a grass-fed steak with steamed vegetables and sauerkraut or enjoying air-dried meats such as biltong with raw sliced vegetables and kimchi, ensures a spectrum of nutrients and flavours.

Chief top tips:

Lightly steam your veggies, especially the cruciferous ones such as broccoli and cauliflower.
Eat raw salads with olive oil.
Use acidic marinades when cooking your meat, or squeeze some fresh lemon on it.
Slow and pressure cook your meat or make stews and stir-fries. Avoid grilling and chargrilling.
Ditch vegetable and seed oils and choose avocado and coconut oil for cooking.
Soak beans, legumes, and grains before cooking them.
Eat potatoes and rice cooked and cooled for your gut health.
Have at least one serve of fermented foods per day.