Resistant starch
Can we convert a carb-loaded meal into a fibre-loaded meal without changing a single ingredient?
Firstly, it’s important to understand the difference between starch and resistant starch.
Starch, one of the main categories of carbohydrates, is a long chain of glucose molecules, found in rice, pasta, noodle, bread, potatoes, etc. When we consume starches, the body breaks it down into glucose which is absorbed in our small intestine to enter our blood.
Resistant starch on the other hand acts very differently, when consumed it 'resists' absorption by the small intestine. Meaning we do not extract any of the glucose from it, it ends up in our large bowel functioning like a fibre. There have been many health benefits associated with resistant starch.
Resistant starch can be formed when certain starchy foods are cooked and then cooled. This means simply preparing starchy foods in advance and reheating them could offer a simple strategy to decrease the glycaemic impact (glucose spike) of a meal and boost fibre consumption.
The research
Research conducted by Dr. Denise Robertson, a senior nutritionist at the University of Surrey, observed the blood glucose levels in individuals after consuming a bowl of pasta over three days. The serving method varied each day: freshly cooked on day one, chilled on day two, and chilled then reheated on day three. Blood glucose levels were monitored every 15 minutes for two hours post-meal.
As anticipated, the freshly cooked pasta resulted in the highest blood glucose spike, followed by the chilled pasta with a slightly lower increase. Surprisingly, reheated pasta led to a 50% reduction in blood glucose rise.
The science behind it
The scientific rationale lies in the concept of starch and resistant starch. The intricate structure of raw starchy foods breaks down when cooked in water. Upon cooling, this structure rearranges itself into resistant starch, which resists breakdown and travels to the large bowel for fermentation by gut bacteria.
The takeaway
By reheating previously cooked starchy meals, we can transform a carbohydrate-heavy dish into a fibre-rich dish without altering any ingredients.
Carbohydrates that have been reheated are also slightly lower in calories, however only marginally so you still need to be mindful of portions. The findings do have potential to help those with pre- and type 2 diabetes, allowing easier control of blood glucose levels. And for the general population, any simple adjustment to increase fibre intake and satiety is worth considering.