The ultimate price of “cheating” on your diet

Over the course of my 30-year career in private practice, there’s one question that consistently comes up in conversation : “Can I cheat on my diet here and there?”

Well, as a diet doctor—and knowing how passionate I am about healthy eating—my answer to that question might surprise you. But first, let’s take a look at what the science has to say…

Harsh effects of a poor diet

A new analysis focused on the brain benefits of a healthy Mediterranean-style diet—one that emphasized veggies and fruit, olive oil, fish, moderate wine consumption, and some whole grains. (Not quite the same as my A-List Diet version, but certainly better than the low-fat, high-carb diets some “experts” try to peddle as healthy.)

Researchers also asked an important question: What happens when you throw unhealthy foods into the mix—like fried foods, sweets, refined grains, and processed meat?

Well, the results shouldn’t be too surprising. But let’s dive into the details…

The study looked at more than 5,000 older adults, all part of the Chicago Health and Aging Project, conducted between 1993 and 2012. Researchers evaluated how closely each subject stuck to their Mediterranean diets. But they also looked at how often the subjects fell into Western diet patterns—that is, how often they indulged in high-carb, sugar-laden, ultra-processed garbage.

Then, they looked at the link between Mediterranean diet adherence scores and changes in overall cognitive function—including memory and perceptual speed.

Unsurprisingly, the subjects who stuck most closely to the Mediterranean diet—and limited their intake of Western junk food most restrictively—were also the ones who experienced the slowest cognitive decline.2

In fact, people with the highest Mediterranean diet adherence scores were the equivalent of nearly six years younger, cognitively speaking, compared to subjects who adhered to their healthy diet the least.

But more importantly, this analysis shows that Western diet patterns significantly dragged down cognitive health. And subjects who ate more of the Western diet didn’t enjoy any of the brain-saving benefits of the Mediterranean diet.

I don’t know about you, but that’s more than enough reason for me to make smarter dietary choices—and to pass on cake and fries—more often than not. (And I love these indulgences as much as the next person, to be clear.)

And when it comes to diet cheat days? Well, the trouble is, most people seem to think of these as a daily occurrence. When really, indulging “here and there” has to be very hereand… very there

Redefining “cheat days”

As this study shows, consistently eating healthy—think more leafy greens and other vegetables, fresh berries, olive oil, nuts, lean meat, and fish—means preserving your brain (and body). And consistently gorging on processed garbage, grains, and sweets leads to a lethal tailspin of inflammation, chronic disease, and cognitive decline (as I also discuss on pages 5 and 6).

So, even though cheat days may help to make any diet easier to maintain, indulging every day ruins the ultimate effects of a healthy diet. (And if you’re doing it every day, is it really a “cheat”? At that point, it’s just as much of a habit as healthy eating.)

The bottom line is this: No one eats perfectly all the time—not even me. But here, we have a study that states quite clearly that consistently “cheating” on your diet isn’t actually harmless. Which is why I will always encourage you to strive to do your best, every single day—as the payoff will be paramount for years to come.

But when you do give yourself the very occasional “cheat day”? By all means, enjoy it. And then, get right back on track.


Agarwal P, et al. “Unhealthy foods may attenuate the beneficial relation of a Mediterranean diet to cognitive decline.” Alzheimer’s Dement. 2021 Jan 7.