While pedaling at more than 30 miles per hour and well ahead of the other racers, two cycling pros bumped wheels. They lost their balance, hit the pavement, and slid across it for about 15 feet.

Once they came to a stop and stood up, their shorts and shirts were shredded. What those tears exposed looked like raw meat.

The television commentator simply said, “Ouch.”

Just thinking about that should give you the heebie-jeebies. And so should this.

A recent study found if you eat a diet high in sugars or high in both sugars and fats, you’re likely doing damage to your memory. Damage that can’t be undone by switching to a healthier diet.

While you’re surely well aware of the other health damage that can result from eating either way — like obesity, type 2 diabetes, and cardiovascular disease — switching diets in these instances (often in concert with other lifestyle changes) typically reverses or ameliorates the disease. But the researchers who conducted this systematic review of the cognitive and behavioral effects of a high-sugar and high-fat diets found the part of the memory lost from eating this way never comes back.

At least in rodents.

But don’t pooh-pooh this discovery published in May by Nutritional Neuroscience because rodents rather than humans were studied. Instead, consider why Michael D. Kendig, PhD, the senior author of the study and senior lecturer in the School of Life Sciences at the University of Technology Sydney in Australia, tells Medical News Today why animals are often preferable in diet studies.

Change someone’s diet for the better, Kendig explains, and “multiple aspects of lifestyle are likely to change.” They’re more likely to exercise more, reduce or cut out consumption of alcohol, and make other healthy changes as a result of “feel[ing] more confident about their ability to look after themselves.”

All of which makes it “more difficult to isolate the effects of nutrition specifically” with human subjects.

So Kendig and colleagues screened 3,291 previously published papers and found 27 that met their criteria. These studies fed rodents a high-fat diet, a high-sugar diet, or one that fed them both and then followed that diet with one where the rodents consumed normal rodent “chow.”

On the average in these studies, the rodents ate the first diet for 9 weeks and rodent chow — what the researchers call “the reversal diet” — for 6 weeks. “Although extrapolating [these time periods] to humans is difficult and imprecise,” the researchers cite past estimates to suggest the equivalents here are 5 and 3.5 years.

And although the reversal diet did indeed lead to memory recovery in the rodents first fed a high-fat diet, recovery of memory was “incomplete” in those fed a high-sugar diet or a high-sugar and high-fat diet, with their performance on memory tests at the end “remaining significantly poorer than in chow-fed controls.” Such study results might lead you to believe an impassioned plea from me for you to reduce or even abstain from eating sugar will come next.

Instead, I’ll confess to an ulterior motive behind beginning this article with a mention of professional cycling. It’s because even though the pros are still crashing as often as before, they’re definitely going faster in races.

That’s obvious by the dozens of faster winning times in annual races over the last few seasons. Here’s one so unbelievable you’ll think it’s a typo.

The winner of this year’s Paris-Roubaix, that oh-so famous 160-mile race that includes 34 miles of uneven — sometimes even jagged — cobbled roads, bested the prior record set in 2024 by 4 minutes and 32 seconds.

Yet even more unbelievable is that the last place finisher this year actually recorded a faster time than the 2018 winner.

Dr. Julien Louis, who works with all types of professional sports teams and primarily for Liverpool John Moores University, is just one of the many experts who say high-carbohydrate fueling is the “biggest reason” for this surfeit of fast times. And high-carb fueling means (yes, you guessed it right) consuming lots and lots of sugar.

Amounts you might find hard to comprehend.

For years, the standard advice in the cycling world was for a typically built male to consume about 280 calories of carbs in different forms of sugar per hour on the bicycle. Now, however, most pros ingest double that amount during racing and hard training.

Yet just a few years ago many of these same cycling pros, especially the ones doing ultra-distances — were limiting their ingestion of carbs and replacing them with fats.

That just goes to show what you’ve read here more than a few times before. That the field of nutrition is always evolving. You are, too.

So you need to stay abreast of the latest health and fitness findings and then when it makes sense craft common-sense experiments based on both.