For the first time, the US government is encouraging people to avoid “highly processed” foods, which it says are the main culprits behind diet-related diseases. But this recommendation puts many Americans in a tricky spot. Studies show that many people want to cut back on ultra-processed foods in their diets, but have trouble identifying which foods fall into that category.
“I think advertising is very good at making people think foods are minimally processed when, in fact, they are ultra-processed,” says Alexandra DiFeliceantonio, who studies the neuroscience of food choice at Virginia Tech.
Ultra-processed foods are industrialized products that contain ingredients rarely found in your kitchen, like preservatives, artificial sweeteners, colorings, natural flavors, and emulsifiers. Numerous studies have shown that these foods increase the risk of a range of health problems, including diabetes, heart disease, depression, and obesity.
“When people ask me about ultra-processed foods, they are usually more confused about grains, carbohydrates, and starches,” says Dr. Dariush Mozaffarian, who directs the Food is Medicine Institute at Tufts University. These foods include breads, cookies, pretzels, snap peas, veggie sticks, pastas, and puffed rice or corn. “People want to know how to choose healthier versions of these products,” he says.
That’s why Mozaffarian gives his patients two practical rules to follow when choosing grains and starches: the 10-to-1 test and the water test.
1. The 10-to-1 Test
“A food should have at least 1 gram of fiber for every 10 grams of carbohydrate,” says Mozaffarian. For example, if you are buying a granola bar, check the nutrition label. If there are 30 grams of total carbohydrate in the bar, then it should also have at least 3 grams of fiber. Otherwise, choose another bar. This test, he says, ensures that the foods are not just made of refined flours and sugars. “This way, there is a balance between refined starches, whole grains, bran, seeds, and other healthy ingredients,” explains Mozaffarian.
And, he adds, the food should also pass the “water test”.
2. The Water Test
Just take the starchy food — say, a piece of bread, a cookie, a pretzel, or cereal — and put it in a glass of water. Leave it in the water for three or four hours and observe what happens.
Observe specifically if the grain or starch dissolves or falls apart in the water, he says.
Minimally processed grains, like whole wheat breads and thick rolled oats, still have the plant cell wall intact, which surrounds the carbohydrate chains and forms a kind of shield or barrier around them. The plant cell wall protects the carbohydrates from dissolving in water.
So, if the carbohydrate does not dissolve in water, it is likely a minimally processed food, says Mozaffarian. And it is a healthy choice, because, he says, the cell wall plays another important function: it makes the grain harder to digest.
After ingesting a carbohydrate, enzymes in the mouth and stomach break down the starch into simple sugars, which then enter the bloodstream. In a way, says Mozaffarian, the water test simulates the process in the digestive tract.
Enzymes cannot act on the carbohydrates when they are protected by the cell wall. Thus, the digestion of minimally processed grains is much slower than that of ultra-processed grains. This slow digestion is beneficial, says Mozaffarian. “It does not overload the liver and the hormones responsible for metabolism.” And, in the long term, it reduces the risk of weight gain and diabetes.
This slow digestion also means that the carbohydrate travels further in the intestine, where it can feed the microbes in the large intestine, called the microbiome. You need a healthy microbiome to thrive.
On the other hand, ultra-processed grains and starches do not travel far in your intestine due to how they are manufactured, says Dr. Meroë B. Morse, assistant professor at MD Anderson Cancer Center. Companies, in practice, pre-digest the grains, corn, or potatoes, and in that process, remove the plant cell wall. “The grain or starch is ground into its individual ingredients and then repackaged and agglomerated,” she explains.
Thus, the enzymes in your intestine quickly break down the carbohydrates into simple sugars.
“These foods are digested very quickly in the stomach and can cause a glucose spike,” explains Morse. “And when there is a glucose spike, insulin levels tend to rise.” Over time, these spikes can contribute to insulin resistance and, eventually, diabetes, she says.
Therefore, when choosing grains, starches, and other carbohydrates, you should opt for those that stay intact both in your intestine and in a glass of water.
That’s where the water test comes in.
A Simple Experiment
A few weeks ago, my 10-year-old daughter and I baked a whole wheat bread in our kitchen. And we decided to submit it to the water test.
For comparison, we bought a French baguette at the supermarket, which contained preservatives, dextrose, wheat gluten, plus dough conditioner and crumb softener.
We took a piece of each bread, put them in two glasses of water, and waited about three hours. Then, we examined each piece.
The homemade whole wheat bread absorbed some water but remained intact, and there were no signs of the starch dissolving. The water stayed clear. Bingo! Our homemade whole wheat bread passed the water test with flying colors.
But the French baguette had transformed remarkably. “Wow!” exclaimed my daughter, as she took the bread out of the glass with water. “It looks like a sponge, or goo, or playdough!”
The baguette absorbed a huge amount of water and nearly turned into a kitchen sponge, the kind you can wring out and reuse. Moreover, the water in the glass was cloudy and white because the starch had begun to dissolve. Bzzzt! The baguette failed the water test. This result confirmed that this bread is ultra-processed.
But the water test did something more for my daughter. It helped her understand — and see firsthand — how ultra-processed breads can look similar to homemade ones but act very differently inside our bodies.
“It’s kind of gross,” she said, while squeezing the ultra-processed bread piece like a sponge. “Bread shouldn’t be like that.”
Source: npr.org by Michaeleen Doucleff