Cooking Methods for Optimum Nutrition

Optimising Nutrition

It is easy to forget when preparing, cooking and storing foods that all of these can have a significant impact on the quality, freshness and nutritional value of foods. You may be unknowingly removing a large proportion of vital antioxidants, fibre and vitamins and minerals from the foods you eat before you have even started. To gain maximum goodness and nutrients from your foods and make sure they are providing optimum health benefits for you, it’s important to utilise the best cooking, storing and preparation methods to preserve the nutritional values present in foods. By doing this we can not only enjoy food, but we can rest assured that what we are eating is doing us the most good!  


There are many ways in which different foods can be prepared, cooked and stored and these varying methods can have either a positive or negative impact on the nutrient content of the food. Different foods often require different cooking and preparation methods in order to best preserve their nutrient content, so let’s take a look at how we can optimise our nutrient intake.

Preparation of vegetables

Christmas is almost upon us and vegetables are an important part of any Christmas dinner, especially the iconic Brussel sprout!! Many people still insist on peeling vegetables during the preparation stage, yet this is totally unnecessary and removes a large proportion of fibre and a high concentration of nutrients that are found in the vegetable skin, or just below it. It is far more beneficial to just thoroughly wash the food, which then removes the need for peeling and retains maximum nutrients.  


Cooking of vegetables

There is nothing worse than soggy, limp, discoloured vegetables that try to hide themselves under the gravy in shame. Vegetables should be slightly crisp (Al dente), and still retain their bright colour and this can be achieved by steaming them rather than boiling them. Many vegetables are packed full of essential water soluble vitamins (the B Vitamins and Vitamin C), which means if these vegetables are boiled in water, many of these vitamins leach out of the vegetable into the surrounding water that we then pour down the drain. When steaming vegetables, this ‘leakage’ of vitamins is only minimal and the nutrients remain within the vegetable. If you still insist on boiling vegetables, then make sure you use the water in which you cooked them, as this will contain the nutrients from the vegetables. This water can then be used to make the gravy or can be used in soups or stocks.

Roasting vegetables is also a good method of cooking to preserve nutrients, if done correctly. You can’t beat crispy roast potatoes at Christmas time, but many other vegetables can be successfully roasted too, including peppers, butternut squash, onions, broccoli, tomatoes, courgettes and carrots. As mentioned above, there is still no need to peel any of these vegetables, just roast them with their skin on with a little bit of olive oil. Cooking at high temperatures can result in nutrient loss, so it is much better to roast your vegetables on a slightly lower heat, than cremate them at speed! Whilst preparing your vegetables to roast, don’t chop them too small, chop them in larger chunks as this will reduce the surface area exposure once in the oven and results in overall less nutrient loss.

Preparation of meat and fish

The healthiest way to prepare any meat and fish before cooking is to remove any obvious fat that you can see. Red meat in particular, especially lamb, contains fat within the meat so trimming off the obvious fat will be far better for your health and your arteries will be thanking you! Although it is often best to cook meat with the skin on to preserve the meats juices (as in the case of chicken or the Christmas turkey), this is definitely best removed before eating due to its high fat content.

Cooking of meat and fish

The best cooking methods for meat include roasting or grilling and these should be done in such a way that fat can be drained away from the meat during the cooking process. It is important here not to burn the meat or over cook it, as high temperature cooking techniques such as grilling and ‘doneness’ level of red meat has been linked to cancer, particularly colorectal and pancreatic cancer.

Fish can be baked in the oven in a ‘tin foil parcel’ to keep in moisture and can also be poached successfully, both of which are methods that best preserve the flavour of the fish and health benefits associated with its consumption. Due to fish’s delicate nature, it is best not grilled at high temperatures, for the same reasons as stated above.

Microwave cooking

The invention of the microwave has been a time saver for millions of people over the years, although some people still worry about possible risks of cooking food in this way due to its association with radiation. As stated by Cancer research UK, Microwaves heat food, but do not make any changes to it that aren't made in any other cooking method. So they do not make food any more likely to cause cancer. Like any other cooking method however, there is a risk of nutrient loss in some foods, but using a microwave has been shown to be a preferable cooking method compared with boiling in preserving nutrients in some foods and vegetables, especially vitamin C, although steaming is still a better option.

Although there are many ‘scare’ stories on the internet suggesting the microwave cooking methods destroy nutrients in food, or cause food to become toxic and harmful to health, there is no scientific evidence to support these wild statements. Of course microwave cooking changes the molecular structures of foods, but that occurs in all methods of cooking and is not unique to microwaving.

Raw versus cooked

There are of course some foods that should never be eaten raw, but other foods can be eaten both raw and cooked. Contrary to popular opinion, raw is not always best. For example tomatoes contain a phytochemical called Lycopene, which is actually a pigment that gives tomatoes their red colour and has been shown to have many health benefits including cancer protective properties. Research has shown that the Lycopene content of tomatoes actually increases when it is cooked and as higher lycopene intake has shown increased health benefits, this is one food that is better cooked than raw!

Carrots also fall into this category, as research generally shows that when carrots are cooked their antioxidant levels are higher compared to when in their raw state. This is specifically found to be the case with the antioxidant called Beta carotene that is responsible for giving carrots their orange colour.

Broccoli is another food packed with health boosting properties and again can be eaten raw or cooked. If you choose to cook it, make sure you steam it as this method increases its folate concentration by almost double compared to when raw! However, broccoli contains about 40% more vitamin C when raw as opposed to cooked, so when it comes to eating broccoli, variety is the name of the game!

Not many of us would choose to gnaw into a raw onion, but many people add them raw to salads. However cooking onions improves the flavonol content (a phytochemical which has health boosting properties) of them, so roasting or boiling them is best.

Food storage

The best storage devices we have in this modern day are the fridge and freezer allowing food to be kept cold and preserve its shelf life for quite a long while. However even freezing or chilling foods will not make food last forever, although freezing foods still allows nutrient content to be retained successfully. This can explain why frozen fruits and vegetables are just as nutritionally advantageous as fresh fruit and vegetables as the ‘deep freeze’ maintains their nutritional status, sometimes even better than fresh produce as we cannot be sure how long these ‘fresh’ products have been on the shelves and although we perceive it to be fresh, most likely it has been there for many days before we even buy it. 

Within reason most products are absolutely fine to freeze and are still as nutritious once defrosted (as long as not over cooked during the thawing process). Even dairy products such as Delamere Dairy’s goats’ milk and cheese can be successfully frozen, which can be especially handy if you are going away on holiday or a weekend break and are unable to buy milk or cheese on your way home! So if you are heading off this Christmas and not sure when you will next get to the shops, why not decant some Delamere Dairy goats’ milk into ice cube trays and freeze. This way on your return home all you have to do to make that much needed cup of tea is get a goats’ milk ice cube from the freezer and add to your cuppa!

Processed foods often contain a lot less nutrients than fresh foods, as the processing process can cause loss of certain nutrients, for example through excess heating methods.

Fresh vegetables should be kept at cold temperatures in the fridge vegetable compartment as this temperature helps retain their nutrient value best. Root vegetables such as potatoes, sweet potatoes and carrots are best kept cool and slightly moist, so again can be stored in the fridge. When it comes to fruit, these should be ripened at room temperature and then either eaten straight away or then placed in the fridge to prevent nutrient losses.

With regards to cooking foods, there is not really one optimum method that embraces ALL foods. Research consistently shows that the best cooking methods vary depending on the specific food and it is unfortunately not a case of ‘one size fits all’. However for most vegetables, research has shown that pressure cooking and boiling methods result in the greatest nutrient and antioxidant losses, whereas steaming and microwaving methods are best for minimising losses. Remember to store your foods correctly to maximise shelf life and nutritional value. This is especially important when bulk buying food over the Christmas period, although for many people over the festive period the most common storage method for all food is in their stomachs!!

  • Effects of Different Cooking Methods on Nutritional and Physicochemical Characteristics of Selected Vegetables, 2007. Journal of Agriculture and Food Chemistry
  • Influence of Cooking Methods on Antioxidant Activity of Vegetables, 2009. Journal of Food Science
  • Stability of Ascorbic Acid in Vegetables Submitted to Different Methods of Cooking, 2014. The Natural Products Journal.
  • A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes, 2015. International Journal of Gastronomy and Food Science
  • Meat and Cancer. 2010. Meat Science

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