Whether you want to save time in the kitchen, lose weight, or simply eat healthier, the way you prepare and cook your food can make all the difference. That’s because the way you cook your food affects the amount of nutrients it contains. Some methods can make nutrients more accessible or easier to digest, and with others, you may end up with fewer nutrients than you began with. Clearly, not all cooking methods are created equal. And when it comes to preserving the maximum amount of nutrients in your food, it’s important to select the right cooking technique.
In this article, we explore some of the most common cooking methods and the nutritional benefits (or drawbacks) that are linked to each. We also share some tips on the best way to cook your foods to help prevent nutrient losses.
Which nutrients are most affected by cooking?
To help you unlock the maximum number of nutrients from your food, it’s helpful to know which nutrients are more vulnerable to cooking methods.
As a general principle, cooking foods – especially in a lot of water or fat at high heat – reduce the nutritional value of foods. And the longer you cook your food, the more nutrients will be lost.
Water-soluble vitamins, which include vitamin C and B vitamins (specifically folate and thiamine) are the nutrients most affected by cooking methods. These vitamins tend to be more sensitive to heat and migrate into boiling water when cooking – so it’s best to limit the amount of water and not overcook your food.
Fat-soluble vitamins, which include vitamins A, D, E and K, can also be impacted by cooking. In general, they are more stable when cooked. But when cooking with large amounts of oil, these vitamins are more likely to leach into fats and reduce. So it can be helpful to use an air fryer or a microwave to limit nutrient losses.
Cooking methods using dry-heat
Dry-heat cooking involves cooking with hot, dry air (usually well above 100°C).
Grilling involves cooking over a grill, where the heat is applied from underneath to cook the food, with or without added fats. Heat-sensitive vitamins, such as B vitamins and vitamin C, can be lost through cooking. But with grilling, your food is immersed in the heat for less time (compared to some moisture cooking methods), and is, therefore, able to retain more of its nutrients.
Roasting and baking
Both roasting and baking involve cooking food in an oven with dry heat. Roasting is often used to cook fish, meats and vegetables, and baking is mostly used for cakes, muffins, bread, and other foods made with dough. Nutrient losses are fairly small with these cooking methods, except for B vitamins.
Microwave cooking preserves nutrients better than other common cooking methods. Since microwaving cooks food quickly, heats food for the shortest amount of time, and uses minimal amounts of liquid, it generally has the least nutrient-damaging effects.
Cooking methods using moist-heat
Moist-heat cooking uses water or steam to transfer heat to the food.
Boiling, simmering and poaching
These three cooking methods are all moist-heat cooking methods that surround food entirely in water. The only difference between boiling, simmering and poaching is the water temperature (poaching is around 82°C, simmering is around 85–93°C, and boiling is 100°C).
Out of the three, boiling your food results in the greatest loss of nutrients. As you might have guessed, water-soluble vitamins, vitamin C and B vitamins, are the most vulnerable to breaking down when boiling your food.
One study even found cauliflower and courgettes to be particularly vulnerable to a loss of nutrients through boiling, losing more than 50% of their antioxidants.
Cooking tip: Since water-soluble vitamins leach out from your veggies into the water, look to also incorporate the water in your cooking. Instead of pouring the water down the sink, make yourself a soup or stew. Also, look to cook your food in smaller amounts of water to minimise the loss of vitamin C and B vitamins.
Of all the moist-heating methods, steaming is one of the best methods to preserve heat-sensitive nutrients, since the food doesn’t come into contact with cooking water.
Cooking tip: If you find that steamed food tastes bland, you can add spices to the steaming liquid, or you could line your steamer with fresh herbs for some extra flavour.
Cooking methods using oil
Deep-frying and stir-frying are two common methods of cooking with oil.
Deep-frying involves fully submerging your food in oil. Considering that foods cook fairly quickly, it doesn’t contribute to as much nutrient loss as boiling and other moist-heat cooking methods. It’s worth noting that fried foods also absorb fat, resulting in higher energy-dense meals, meaning the fat content of your foods can shoot right up!
With stir-frying, the food is cooked over medium to high heat using a small amount of oil. Because stir-frying is a quick cooking method, minimal nutrients are lost. Also, the addition of oil can in fact help improve the absorption of plant compounds and antioxidants. Just be sure to use healthy cooking oils that are high in monounsaturated and polyunsaturated fats (such as olive oil), and avoid overcooking the food.
Cooking tip: Air frying your food is both a tasty and healthier alternative to frying your food. It can cut calories by 70% to 80% and cooks food with rapidly circulated dry heat and little to no oil. An air fryer is also less likely to deplete nutrients compared to deep frying and boiling your food.
The numan take
Cooking foods using only small amounts of fat or water at a lower temperature for a shorter amount of time will boost the nutrient content of your food. Out of all cooking methods, microwaving may be the best method for preserving the nutrient content of your food, and steaming comes in a close second.
There is no one-size-fits-all method when it comes to cooking. But for the most health benefits, aim to eat a variety of raw and cooked vegetables in a way that you enjoy eating them, to help maximise your nutrient intake and provide balance to your diet.