Never eat berries and bananas together – and other tweaks to supercharge your food
Usually it’s assumed that a diet overhaul is needed to eat healthier. But actually, simply making tweaks to foods you already consume can amplify their health benefits dramatically.
Eat reheated rice, potatoes and pasta
Raw starchy foods, such as potatoes, pasta and rice, contain chains of glucose molecules that are hard to digest and would therefore cause a gradual rise in blood sugar. However, these chains weaken during cooking, meaning they release an immediate burst of glucose into the bloodstream when eaten.
Over time, eating too many foods that cause blood sugar spikes may lead to Type 2 diabetes and cardiovascular disease.
But a simple tweak to how you prepare these foods changes the effect they have. Rather than eating them straight away, allowing them to cool and then reheating them means they are digested more slowly and provide a more gradual release of glucose.
“When you cool food and store it after heating it leads to a process of retrogradation – this means the starch regains an ordered chemical structure that is more resistant to enzymatic digestion,” says Naveed Sattar, a professor of cardiometabolic medicine at the University of Glasgow.
“[This means there is] a slower breakdown into its building blocks like sugar molecules – in turn this means a slower release of calories. In this way one can feel satiated but absorb less calories if some of the starch is not absorbed.”
Research suggests that then reheating these foods further increases the resistant starch content.
Freeze and toast white bread
The same science applies to white bread. Rather than eating a slice straight from the packet, freezing it and toasting it can lower the spike in blood sugar that it causes.
“You end up lowering the glycemic index of the bread. This means it’s broken down more slowly, causing a more gradual rise in blood sugar levels,” explains the NHS surgeon Dr Karan Rajan in a recent TikTok video which has raked up almost one million views.
“If you take a slice of white bread and then freeze it, and then defrost it and toast it, you could lower the glycemic index of the bread by almost double,” he adds.
“This all happens because more retrograded starch is formed and retrograded starch is a type of resistant starch which is beneficial for your gut health because it acts more like a fibre.”
Don’t mix berries with bananas
Whether it’s whizzed up in a smoothie or in a fruit salad, strawberries and bananas are a common combination. However, eating them together can bring down the flavanol count.
These compounds are found in fruits such as berries, apples and plums, as well as green tea and dark chocolate and have been linked to better cardiovascular and cognitive health. Everyone should aim to consume around 400 to 600mg per day, according to Gunter Kuhnle, a professor of nutrition and food science at the University of Reading.
However, bananas are high in polyphenol oxidase, an enzyme that destroys the majority of flavanols found in food. One study by Prof Kuhnle and colleagues found that adding a banana to a berry smoothie slashed flavanol intake by 84 per cent.
“Bananas are a bad combination with berries as they can destroy flavanols,” he says. “It’s mainly making them as a smoothie – cutting them up in a salad won’t have much effect. There will be some reaction in the stomach, but not much.”
There are other downsides to smoothies – blending fruit increases its sugar content which can, over time, contribute to tooth decay and increase the risk of Type 2 diabetes.
Have a glass of orange juice with your steak
Dr Maria Traka, a research leader in food and health at the Quadram Institute, recommends pairing a steak with a glass of orange juice to ensure the body absorbs more nutrients from the meal.
This is because eating foods with plenty of vitamin C alongside iron-rich foods increases the amount of iron the gut can absorb. Iron is vital for making red blood cells, which carries oxygen around the body.
Conversely, calcium makes iron less soluble and reduces its absorption.
“Make sure you don’t drink milk or tea/coffee next to your steak but instead a glass of orange juice. That way you can increase the iron that is absorbed. That is particularly relevant for young girls and women where iron deficiency is common,” she says.
Only cook broccoli for three minutes
Microwaving broccoli for just a few minutes – so it still has a bit of a bite, rather than boiling it to the point of mush – can make the vegetable even healthier.
“Three minutes in the microwave will maximise the amount of sulforaphane you get,” says Dr Trakka.
Broccoli contains glucoraphanin, which is converted into the chemical sulforaphane by an enzyme called myrosinase as the vegetable is chewed in the mouth. Sulforaphane has been linked with cancer prevention, cardiovascular health and blood sugar control, she notes.
However, this process only happens if broccoli is eaten when it still has some crunch to it.
“If we cook the broccoli too much then the enzyme myrosinase is deactivated and then you have to rely on your gut microbiota to do the conversion. This is OK but it is not as efficient,” Dr Traka explains.
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