Is raw really more?
Updated: Feb 24, 2019
Is a raw food diet more nutritious than cooked food?
Before cooking existed, humans altered foods in many ways. For example, chewing food breaks down fibres, therefore improving the digestibility. Saliva breaks down plant enzymes, altering the absorption of nutrients. While simply exposing the food to oxygen or sunlight alters the nutrient profile.
When humans learnt to use and control fire, our evolutionary history changed forever.
Learning to control and use fire gave way to a new era of nutrition. Cooked food. This new technique altered the nutrient profile of foods in even more ways. Our ancestors gained more energy, a greater diversity of food and nutrients while food became safer.
Many scientists have hypothesized that the ability to cook food is directly linked to the development of bigger brains and longer life expectancy.
But now that we have big brains and an (over) abundant energy supply, is cooking still beneficial? Or should we all go back to raw?
Cooked vs Raw: vitamins and minerals?
Vitamins and minerals are essential nutrients you must get from your food and drink, so you want to make sure there are plenty packed into your meals. The good news for cooked food is that most of these nutrients have only minimal losses when cooked.
The US Department of agriculture has identified nutritional losses for 16 vitamins and 8 minerals in a range of different cooked foods. The main culprits are vitamin C, thiamine and folate. Even then, the amount retained after cooking rarely drops to less than half of the original value.
Although iron isn't effected by cooking, Oxalates are a compound that bind to plant-based sources of the mineral iron, preventing absorption. Spinach is high in iron but also oxalate meaning it is not actually a good source of iron. However, by slightly steaming spinach, some oxalate will leach out into the water. Lightly cooking is best to retain the Vitamin C to help with the absorption of this newly available iron.
Will you lose your antioxidants?
There are hundreds of other bio-active compounds present in your food, many with benefits to your health. From anti-inflammatory agents and antioxidants to molecules with anti-cancer and antibacterial properties.
Cooking losses from these other nutrients have been found to be small. In many cases, cooking can actually improve the availability of these molecules by breaking down the fibrous molecules they are trapped in.
Lycopene, a beneficial antioxidant found in tomatoes, is higher in cooked tomatoes than fresh. This is because the lycopene is trapped within fibrous parts of the cell wall that your body cannot break down. Cooking breaks down the cell wall, releasing the lycopene. You lose some vitamin C and fibre but gain a powerful antioxidant instead.
It has also been found that antioxidants in some vegetables such as carrot, broccoli and zucchini were better preserved when cooked rather than when raw.
Of course, cooking isn't beneficial to all nutrients in food. Broccoli contains an enzyme which helps produce a molecule called sulforaphone, a powerful antioxidant. However, this molecule is destroyed by cooking, particularly stir-frying and boiling. Although cooking helps preserve some nutritional qualities of broccoli, others are reduced.
Some things are best destroyed
Not everything in your food will do you good. Bacteria that live and breed in food are a good source of gastroenteritis and food poisoning. Not what you want to get from your food. Heating food above 75 degrees destroys much of the potentially harmful bacteria that live in your food. This is particularly important with animal products. Cooking these foods means you can safely enjoy a wider variety of foods and nutrients.
You can't absorb every single nutrient from the food you eat. You have to make sacrifices. The best bet to make sure you get a range of different nutrients is to eat a mixture of raw and cooked foods.
Switch between fresh salads and cooked vegetable dishes. Use different cooking methods with your vegetables and try not to overcook them.
To make up for the losses of some vitamins and minerals you can eat some fresh foods that are high in the lost nutrients. Vitamin C can be easily gained from consuming citrus fruits or strawberries. Even half an avocado will give you about a third of your needs. Folate is found in green leafy vegetables and fortified breakfast cereals while thiamine is found in a range of foods including wholegrain breads, eggs, fruits and fortified cereals.
Importantly, to get lots of nutrients, you need to eat a wide variety of different foods. Many nutrient-packed foods are wrapped up in fibrous bonds that your body cannot break down. Think legumes and lentils, potatoes and wholegrains. These foods are packed with vitamins, minerals, antioxidants and fibres.
However, eaten raw, they are likely to cause pain and discomfort. Cooking partly breaks down the fibrous bonds, allowing your body to digest them and access the nutrients.
There are many complex reactions that take place between different compounds in your food and within your body that you cannot control.
Cooking can cause some vitamins particularly Vitamin C, thiamine and folate to leach out into cooking water. Eating some uncooked foods high in these nutrients helps to make up for any cooking losses.
Many antioxidant molecules in food are made more bio-available from the cooking process. However, there are others that may be destroyed.
Some things are best destroyed such as harmful bacteria. Cooking helps to make food safer by destroying some of the disease causing bacteria.
Having a mixture of cooked and raw foods helps to ensure you get a variety of nutrients from a variety of foods.
With nearly 75% of UK citizens not managing to eat the recommended amount of fruits and vegetables each day, the focus should be on eating more nutritious foods. Raw or cooked, fresh or frozen. Getting some of the nutrients from your food after cooking, is better than not getting any of these nutrients due to restricting your food variety.