Grains of uncooked jasmine rice are shown in Harrisburg, Pennsylvania, on April 24, 2008. Credit: AP Photo/Carolyn Kaster, File
Social media influencers frequently tout a straightforward method for transforming rice, pasta, and potatoes into lower-calorie options: simply allowing them to cool down after preparation.
Is there validity to these claims? Not entirely, though a growing collection of credible scientific research indicates that cooling these carb-heavy staples post-cooking might indeed support efforts to shed excess pounds.
Over recent years, health and fitness enthusiasts online have championed a technique known as retrogradation. This involves preparing carb-rich dishes, refrigerating them, and then reheating before consumption, with promises of substantially reduced caloric intake.
While retrogradation is a legitimate process, its effects are more nuanced than often portrayed by promoters.
Two kinds of starch
The primary source of carbohydrates—and thus most calories—in these foods stems from starch, which exists in two distinct forms: the tougher-to-break-down amylose and the readily digestible amylopectin. Amylopectin gets metabolized rapidly, causing sharp elevations in blood glucose levels. In contrast, amylose is handled more gradually, helping to maintain steadier blood sugar.
Uncooked versions of these foods, such as raw potatoes, predominantly contain the resistant starch type. However, the heat from cooking alters its structure, shifting it toward the easily digestible form. This transformation explains why individuals managing diabetes must approach starchy meals with caution.
This is the point where online advocates become particularly enthusiastic. Cooling cooked foods initiates retrogradation, effectively reverting the digestible starch back to its resistant form. This change renders it more challenging for the body to process, even after the food is warmed up again.
How does this impact caloric absorption and blood sugar regulation? Scientific insights provide some clarity on the matter.
Research exploring retrogradation’s dietary effects has largely consisted of modest-scale investigations, concentrating on how resistant starches influence glucose levels, especially among those with diabetes.
Since 2015, various experiments have demonstrated that participants consuming rice prepared, cooled, and then eaten exhibited notably lower post-meal blood glucose readings compared to those eating freshly cooked rice. These results have gained broad scientific consensus.
Far less examined is the question of whether this process also diminishes the effective calorie yield from such foods.
It does to some extent, according to Dr. David Ludwig, an endocrinologist and researcher affiliated with Boston Children’s Hospital. He notes, “It doesn’t significantly alter the inherent calorie count of the food itself.” However, he adds, “It could influence hormonal responses and metabolic processes in ways that simplify calorie management.”
Although the calorie-modifying benefits of retrogradation are neither straightforward nor as profound as some influencers assert, it holds potential as a component of a more nutritious dietary approach, as Ludwig emphasizes.
Reducing blood sugar spikes and cravings
Incorporating foods enriched with resistant starch helps dampen the rapid blood sugar increases commonly associated with cooked carbs, Ludwig explains. This benefit extends beyond diabetes management alone.
Investigations reveal that such glucose surges stimulate the brain’s reward pathways, fostering intense cravings that heighten the risk of excessive snacking and larger portions at subsequent meals.
Moreover, these spikes prompt elevated insulin secretion, which not only intensifies hunger signals but also shifts the body’s metabolic priorities toward fat accumulation rather than energy utilization, according to Ludwig.
“Retrograded food breaks down at a slower pace,” he states. “This promotes more consistent blood sugar levels, reduces insulin-driven fat storage, and generally makes it simpler to steer clear of overconsumption.”
So is chilling your pasta, rice and potatoes worth it?
For diets laden with refined starches, the chilling method can partially counteract some adverse effects. Yet Dr. Walter Willett, a professor of epidemiology and nutrition at Harvard T.H. Chan School of Public Health, argues that true benefits require diligent, ongoing application—a commitment he doubts many can sustain.
Furthermore, the technique lacks universal simplicity. Retrogradation’s efficacy varies across grain types; certain rice strains bred for faster cooking times naturally contain less resistant starch. Unfortunately, such details are seldom disclosed to shoppers, complicating decisions on when cooling truly matters.
Willett points out an additional limitation: retrogradation addresses only blood sugar dynamics.
“Cooling cannot replenish the fiber, minerals, and vitamins stripped away during grain refining,” he observes.
A more straightforward strategy, he recommends, involves opting for whole, minimally processed grains prepared through standard cooking methods.
