Raw vs. Cooked - What’s the best way to eat your vegetables?

There are a lot of diet misnomers out there when you’re embarking on a journey to eat healthier. However, when it comes to eating fruits and vegetables, the advice is usually consistent: eat more. But as we head into a new decade of nutrition and scientific research, scientists are continuing to ask questions about the ways we prepare food - and how it might affect how well we digest our food.

Why do we cook food and is it necessary?

Humans are unique in that we are the only species or even organisms on this planet that heats or “cooks” our food before we consume it.

Some researchers have even theorized that it was actually the process of cooking food that pushed the evolution of homo sapiens and allowed brain growth to occur.¹ This led to our brains developing the unique critical thinking skills that we use today. In fact, early humans have been using fire for food preparation for hundreds of thousands of years (some even estimate closer to 1,000,000 years ago!).²

So what about cooked food promoted this giant leap in brain development?

Consider this: the process of cooking can many things, like killing many harmful microbes that grow on foods and can increase the calorie content in food humans has access to in 2 ways:

a. Denaturing proteins to allow for easier digestion in the stomach.

b. Breakdown hard to digest fibers, allowing our digestion process to improve the uptake of essential nutrients.

In some ecological studies, behavioral scientists have even considered how cooking food changed the community dynamic between humans, improving familial roles and evolving the human social system.¹

Ultimately, this enhanced food preparation technique gave rise to the early influences of germ-reduced meals and lowered bouts of food poisoning. Humans had the ability to eat more and be sick less. Sounds like a win, right?

But other aspects of life have evolved, like technology and medicine.

Fewer people get food poisoning and our knowledge of microbes has changed how we grow and clean our fruits and vegetables. Not to mention, although cooking might help breakdown complex fibers in your broccoli or carrots, the impact of high heat can also degrade many of the nutrients you eat. Thus eating raw vegetables may improve your access to many vitamins, such as water-soluble Vitamin C and many of the B Vitamins. Heating can also kill many enzymes within these plants that may be beneficial for digestion as well.³

In other cases, how you prepare your food can also impact your gut microbes. In some cases, cooking the food can reduce anti-microbial enzymes within raw vegetables that can harm beneficial microbes.⁴ Yet, in other ways, certain raw foods can be a better source of nutrition and function as helpful prebiotics.

Which leaves us with the question: which is better?

Just like everything, it depends! For tougher foods like legumes and grains, cooking not only makes it easier to eat but can also break down “anti-nutrients” or compounds that prevent you from being able to access beneficial nutrients. Cooking can also increase the amount of Vitamin A in foods like tomatoes and carrots.⁵ As for other vegetables - you might be better off crunching through and reaping the benefits of them raw. However, each person is unique and has different digestive properties and nutrient requirements, but there are certain rules you can follow to maximize the benefits of your food.

1. When in doubt, don’t boil
Boiling vegetables can often result in water-soluble vitamins leaching out into the surrounding water. Even if you’re quickly blanching them to retain most of their beneficial properties, these nutrients can very quickly leave the plant and reduce their nutrient impact.⁶ The best way to optimize your ingestion of these nutrients is to consume the liquid along with the vegetables, as in soup or stews.

2. Sauteing or quickly pan-frying might be your best friend
The best cooking method to retain nutrients is to quickly toss your vegetables in a pan and heat rapidly for a short period of time. This method (including stir-frying) reduces the level of nutrient degradation while softening the outside fibers of the food to improve proper digestion.

3. Chew, Chew, Chew… keep chewing!
No matter whether you’ve decided to cook your vegetables or eat them raw, chewing is often one of the most underutilized methods humans have to improve digestion. It might seem like a chore (especially with crunchy, raw vegetables like carrots and celery), but the act of chewing instigates your salivary glands to produce several enzymes - like amylase - to begin digesting your food before you’ve even swallowed!*⁷ Toss in the fact that you’re quite literally mechanically tearing apart and breaking down your food and rapidly reducing the amount of work for your stomach in digestion. Interestingly, it can also stimulate satiety signals and reduce the amount of food you consume. Who knew chewing would be your best dieting tool!

The truth is, your diet should combine both raw and cooked vegetables in your diet. Simply consuming one method the entire time means your not optimizing your nutrient potential with your food. To help ease your understanding, here is a shortlist to help you when preparing your next meal:

Foods that are healthier raw:

• Broccoli

• Cabbage

• Cucumber

• Onions

• Garlic

• Green Peppers

Foods that are healthier cooked:

• Asparagus

• Mushrooms

• Spinach

• Tomatoes

• Carrots

• Potatoes

• Legumes

When you start planning your next trip to the grocery store, it’s better to focus on increasing your vegetable intake without worrying too much about preparation methods just yet. There are many ways you can enhance your vitamin and mineral intake through your food that focuses more on a well-balanced and colorful diet.

Furthermore, some of these foods might not even be best for the state of your gut microbiome - something you can learn from the results of your Viome Intelligence Test. Before you grab a batch of tomatoes and start planning on making a rich sauce to boost your lycopene levels - you might need to know whether you should even be consuming tomatoes!

Your intestinal discomfort might have less to do with the cooking method and more to do with the current state of your gut ecosystem.

Best plan of action? Check what’s happening inside you first - and then begin planning out the best ways you can balance a higher intake of fruits and vegetables right for you, both raw and cooked. Your personalized dietary recommendations from Viome help you choose the best fruits and vegetables to optimize your health, improving your chances of getting the benefits out of everything you eat!

References:

¹ Wrangham, R.W., Jones, J.H., et al. (1999). “The Raw and the Stolen. Cooking and the Ecology of Human Origins.” Current Anthropology. PubMed. 

² Brain, C.K., Silent, A. (1988). “Evidence from the Swartkrans cave for the earliest use of fire.” Nature. Nature.com.

³ Chen, N.G., Gregory, K., et al. (2011). “Transient model of thermal deactivation of enzymes.” HHS Public Access, Author manuscript. PubMed Central.

⁴ Weller, N. (2019). [Cooked food and the microbiome]. Science News. sciencedaily.com.

⁵ Talcott, S.T., Howard, L.R., et al. (2000). [Metabolite changes in processed carrot puree]. Journal of Agricultural and Food Chemistry. PubMed.

⁶ Kimura, M., Itokawa, Y., et al. (1990). [Losses of nutrients in cooked foods]. Journal of Nutrition Science and Vitaminol (Tokyo). PubMed.

⁷ French, D. (1981). [Information on amylases]. Basic Life Sciences. PubMed.