The effects of processing food are widespread, today’s modern diets often contain foods processed by a factory where machines break down/refine the food for us, a job which our bodies are perfectly capable of doing, resulting in a quicker digestion and faster energy release. These foods are usually lacking in nutrients and rich in chemicals and toxins such as colourings, artificial flavours and preservatives, all added during the processing to enhance food appearance and taste.
Brown rice is rice with only its outermost layer removed (the hull), white rice however additionally has the bran and most of the germ layer removed then is ‘polished’ to remove the aleurone layer, most of the nutritional value of the rice is removed with the layers – all that remains is a refined starch. Brown rice has a GI of 55, white rice is somewhere around 75.
Or more specifically flour. Converting brown flour to white flour is similar to rice, the bran and germ layers are removed. In some countries the law dictates that white bread must be fortified with vitamins and minerals, ironically this process just replaces some of the nutrients removed with the bran and germ layers. Wholegrain bread has a GI of 49, white bread 71 and french bread (say a baguette) is somewhere in the 90′s. Brown/white pasta is made with brown/white flour so the effects are similar.
Not all sugar is the same, there are many different types such as sucrose, fructose, dextrose and even high-fructose. The gist is the same, the more it’s refined the higher the GI.
Other unhealthy processed foods are packaged high calorie snacks such as crisps, frozen or ‘fresh’ readymade meals and fish fingers, sugary breakfast cereals and processed meats. Food companies know that refined foods usually taste better and they want to make a profit so they’re going to sell the most tasty food they can (maybe ready made meals are an exception, they taste awful).
Not all processed foods are unhealthy, milk for example is better when consumed after pasteurisation. Frozen vegetables are often a better choice as their vitamins and minerals are preserved at the time of freezing.
Processing food doesn’t just make it higher GI, it also removes nutrients. Our bodies digest high GI foods faster than low GI ones, so we eat more calories but the nutritional value is less.
It’s hard to avoid processed foods and ready-made meals in today’s fast-paced world, but you can make a better choice by buying foods made with whole grains, or that are low in sodium and calories.