Dr Karan Rajan, an NHS surgeon and lifestyle guru, has shared his ‘favourite food science hack’ which can reduce calorie intake by up to 50% and even lower the risk of colon cancer
An NHS surgeon and lifestyle expert has revealed a zero-cost cooking trick that can slash carbohydrates and calories by “up to 50%”.
Dr Karan Rajan, known for his health advice on Instagram, is fully supportive of reheating carb-loaded foods. “If you love rice and you love leftovers, this is going to be your favourite food science hack,” he said with excitement.
Delving into the details, Dr Rajan shared: “Pretty much any leftovers that contain carbs – rice, bread, pasta, potatoes, legumes, oats – when you cook it and cool it or freeze it, then reheat it, it will magically contain fewer calories when you eat it.”
He then unpacked the science behind this method, known as retrogradation. “Basically the starches in those carb-rich foods are now resistant to digestion in the small intestine – but they do end up in your colon where your gut bacteria can feast on and ferment them,” he explained.
These transformed “carby-leftovers” act as a probiotic, “feeding beneficial bacterial species”. Dr Rajan pointed out that this could also cut the risk of colon cancer and boost bowel regularity and stool bulk.
For diabetics, there’s an added bonus, as resistant starch can lessen the “glycaemic impact”, helping to prevent blood sugar spikes post-meal and aid in maintaining steady blood sugar levels.
Dr Rajan elaborated further on the benefits of resistant starch in maintaining a healthy diet: “Additionally, resistant starch can increase feelings of fullness and reduce hunger pangs because it ferments more slowly in the gut,” he said. “So by increasing satiety [the feeling of fullness], leftover carbs can actually increase portion control and weight management.”
He also provided a nifty tip for those not keen on the idea of cooking and cooling their food suggesting “greenish bananas” as another source high in resistant starch.
One follower shared their experience, saying, “My GP once explained this to me,” and added, “And I love leftovers! Especially potatoes.” And another chimed in with a humorous take: “So that’s why pasta tastes better the second day!”
According to the NHS, meanwhile, its important to only reheat rice on one occasion to avoid any harm coming to babies and young children, who are “highly vulnerable to bacteria”. Advice on its web site reads: “Make sure it’s cooled within 1 hour and then goes straight in the fridge or freezer. Rice kept in the fridge should be eaten within 24 hours. Never reheat rice more than once.”
