Knowing the difference now could make a world of difference later. How much of a difference?

Like knowing the person who’s come to visit you is indeed your grandson - and not your son, despite how much the former reminds you of the latter. Or if that 13-year-old visitor develops dementia or worse by the time he’s receiving visits from his teenaged grandson while at a senior living facility.

Up for debate today is the oh-so important difference between processed foods and ultra-processed foods. But as Hamlet says about a subject equally as important, “There lies the rub.”

The rub here is there’s no clear agreement upon what takes processed foods and turns them into - what more and more research is suggesting you’d be wise to severely limit - UPFs, the oft-used abbreviation for ultra-processed foods.

Challenge me to rapid-fire a list on a game show, though, and I’ll say this: Fish sticks, TV dinners, quick meals containing instant noodles, boxed cake mixes, cookies, candies, hot dogs, and sodas. And it seems as if the people at the University of Texas MD Anderson Cancer Center would name many of the same.

In “What Are Ultra-Processed Foods?” written by Heather Alexander and found at their website, UPFs are characterized as packaged foods using manufactured ingredients “combined in some way to make something that is edible, but it in no way maintains the integrity or nutritional content of the original foods.”

Many of these manufactured ingredients on their own would not be fit for human consumption. Like flavorings, preservatives, enzymes, protein substances.

And oils, fats, starches, and - as often as not - lots and lots of sugar and salt.

While these additions lead to improved texture, taste, and shelf life, new research first available 10 days ago at Neurology’s website suggests those additions may come with a steep cost: eventual cognitive decline.

Chinese researchers at the School of Public Health at Tianjin Medical University reviewed the health information kept in the UK Biobank on more than 72,000 people - all of whom at the onset were 55 years of age or older and did not suffer from dementia. The researchers then compared the info on the 18,000 who had eaten the most UPFs during two 24-hour dietary assessments (about 28 ounces a day) to the 18,000 who had eaten the least (about 8 ounces a day).

They found that in the 10 years after the first dietary assessment, 50 percent more of those who ate about 28 ounces of UPFs a day had developed dementia compared to those who had eaten no more than 8 ounces of UPFs a day.

The researchers continued to crunch the numbers in all sorts of ways, which allowed lead researcher Huiping Li to provide this easy takeaway for Steven Reinberg’s article for Medical News Today: “Diets Heavy in ‘Ultra-Processed’ Foods Could Harm the Brain.” Substituting just 10 percent of the ultra-processed foods you eat with those unprocessed or minimally so lowers your risk of developing dementia by 19 percent.

After reviewing the Chinese research, Samantha Heller, a senior clinical nutritionist at NYU Langone Health in New York City, called the findings “not surprising” and added a caveat. “Ultra-processed foods are both biochemically designed and advertised to increase cravings and desire for these foods.”

Her warning suggests there’s another bit of research she won’t find surprising. It comes from Fang Fang Zhang, MD, PhD, associate professor, Tufts University School of Nutrition Science and Policy, Boston, and his colleagues who reviewed 20 years of data accrued from the U.S. National Health and Nutrition Examination surveys.

About 66 percent of all the calories now consumed by children and teens come from UPFs.

Years ago, we didn’t worry much if kids ate junk because of the belief chubby kids “lean out” during the one or two growth spurts they undergo as teens. But this leaning out isn’t happening often enough anymore.

According to the CDC in 2016, slightly more than 20 percent of teens were obese, about double the rate from 1988.

Which brings us back this article’s intro, the allusion to you as a grandpa, and the question of whether or not your 13-year-old grandson at your age will develop dementia or worse. It’s a question that needs to be considered since there’s a clear link between being obese early in life and cognitive decline later.

Especially in light of a review published in the May 2022 issue of the Journal of Obesity. Using data accrued in NHANES, the National Health and Nutrition Examination Survey, researchers found the leaning out that used to take place in the teenage years isn’t occurring in young adulthood either.

In fact, the opposite is occurring. From their mid-20s to mid-30s, the study found, the average American now gains more than 17 pounds.