Food science is fascinating!

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So many things that I never gave a thought to, turn out to have a significant impact. Food science is far more interesting than I ever thought! For example, I often freeze bread because my favourite brand of ‘proper’ bread isn’t available here, so whenever I go to Wales I buy three or four loaves and pop them in the freezer. And I often eat toast because I do like a couple of slices of toast and marmalade for breakfast, and sometimes I have something like hummus on toast as a lunchtime snack. Cold left-over curry on toast is also a favourite! Now I have found that both freezing bread and toasting it have a significant impact on the nutritional value of the bread! Bread is largely made up of carbohydrates, and when eaten the carbohydrate is broken down during digestion into simple sugars which then enter the bloodstream, leading to a rapid but transient spike in blood sugar. This induces your body to release a surge of insulin to deal with the sugar, and is then followed by feeling sluggish due to lack of energy, meaning you may be tempted to reach for sugary snacks again. How quickly a particular food affects blood sugar is measured using the ‘glycaemic index’ (GI) and plain white bread has a GI of about 70. Foods with a lower GI result in a slower release of sugar, meaning less need for insulin, less of a ‘low’ and more sustained energy levels. Now it turns out that freezing bread reduces the GI, and toasting bread does too. Freezing the bread and then toasting it combines the benefits, reducing the GI to about half the value of the fresh bread! Other things also affect GI values, for example eating the food in question in combination with low GI foods such as fats. So the idea that white bread is a ‘bad’ food because it causes a spike in blood sugar is not that straightforward. And freezing the bread then toasting it and eating it with butter actually reduces the GI substantially, making it considerably lower than many breakfast cereals. Who knew? You can read the original study here https://pubmed.ncbi.nlm.nih.gov/17426743/ All rights reserved. © Text and image copyright Fleur 2023.