In an experiment, Dr Denise Robertson, senior nutritionist at the University of Surrey, measured the blood sugar levels of 10 participants 15 minutes after eating a bowl of pasta over three days. On day one they ate freshly cooked hot pasta. On day 2, they ate cold pasta after it had been chilled overnight. On day 3, they had chilled and reheated pasta.
The experiment showed that the hot bowl of pasta showed the biggest rise in blood sugar levels. The chilled pasta resulted in a lower rise. However, the surprising result came when the team discovered the reheated pasta reduced the rise in participants’ blood sugar by 50 percent.
Why did this happen? The team discovered that the complex structure, which makes up raw, starchy foods, is broken down when cooked in water. When cooked starchy foods are cooled, the structure of the foods reorganises itself and they become a resistant starch, which isn’t as easily broken down by our gut.
As a result of this study, and others conducted since, finding out exactly why the reheating process changes the structure of carbohydrates is currently the subject of more detailed research being funded by Diabetes UK. Since beginning their research, they have stated that as carbohydrates are heated and then reheated, they ‘essentially become a fibre’, and therefore become a type of resistant starch.
What is resistant starch?
Resistant starch is a starch that resists digestion. It avoids getting digested in the small intestine and ends up fermenting in the large intestine. It is sometimes also called fermentable carbohydrate. Resistant starch can be a good thing to include in your diet because these types of carbohydrates do not rapidly convert into glucose and so they are low on the glycaemic index (GI).
What does Glycaemic Index mean and why is it important for weight loss?
We use the Glycaemic Index (GI) to measure the impact carbohydrate-containing foods have on our blood sugar levels. It shows how quickly each food affects your blood sugar level when eaten alone.
Carbohydrate-rich foods such as pasta, rice and potatoes have a high GI. When foods have a high GI our body processes and stores them as simple sugars, causing our blood glucose levels to rise rapidly. In fact, glucose from cooked starchy foods is absorbed almost as quickly as glucose from a sugary drink, which is why we often experience a slump in our energy levels once the ‘sugar high’ has worn off. This often causes us to crave more food. Fibre-rich foods, such as lentils or beans, have a low GI and cause a slow steady rise in blood sugar levels which can help us feel fuller for longer.
Why reheated carbs can be better for you and your waistline.
The World Health Organisation states that resistant starch is the only dietary constituent that shows a convincing protective effect against weight gain. As it does not get converted to sugar quickly, it helps to control your blood sugar levels, and it also helps to improve insulin sensitivity.
Resistant starch is also a prebiotic, meaning it is a substance that provides ‘food’ for the good bacteria in your intestines. Additionally, resistant starch may decrease inflammation and effectively change the metabolism of the bacteria in your intestines. This has led scientists to believe that resistant starch may play a role in preventing colon cancer.
Resistant starch and digestive disorders
Resistant starch reduces the pH level, potently reduces inflammation and leads to several beneficial changes in your colon. The short-chain fatty acids that aren’t used by the cells in your colon travel to your bloodstream, liver and the rest of your body, where they may have various beneficial effects which could help to aid conditions such as inflammatory bowel diseases including ulcerative colitis and Crohn’s disease, constipation, diverticulitis and diarrhoea.
How can we get more resistant starch into our diet?
Foods high in resistant starch include lentils, white beans, chickpeas, bananas and plantains. But if you can’t stop eating bread, slice it and put it in the freezer. This turns some of the easily digested starch in bread into resistant starch. Toast the slice from frozen. The act of freezing and then toasting the bread means that your body gets far fewer calories from the bread. The resistant starch feeds your gut bacteria rather than feeding you.
Instead of eating a pasta or rice immediately, allow it to cool, refrigerate and then reheat it. We would argue a lasagne tastes even better the next day and egg-fried rice is always popular. Potatoes actually have their highest level of resistant starch when they are raw. Fortunately, you can also maximize your intake by eating them cool or by reheating them. We love to include cooked potatoes in a frittata.
It’s clear that resistant starch is more than a health buzzword. It helps to control blood sugar levels, improves insulin sensitivity, helps to feed ‘good’ bacteria in our gut, and can help us to lose weight and prevent disease.
Why not see if you can get more resistant starch into your diet by ordering a meal programme from The Pure Package. Our chefs prepare mouth-watering recipes such as Miso Cod and Sesame Wild Rice, which when reheated by you, results in the development of resistant starch.