Want to feel as outdated as electric typewriters? As obsolete as public pay telephones?

Do what I did recently. Take a book to read to your next doctor’s appointment. Enter the waiting room. Look around.

I saw seven other patients, but not a one noticed me — or the irritating eek-eek emanating from my walker. They were all too focused on whatever video they were watching or game they were playing or fake news story they were reading on their Smartphones.

When I signed in, however, the receptionist noticed the book’s title and asked, “What do you think of the book?”

I replied immediately, honestly, and a bit cryptically: “That I read this story before.”

So you are not as confused as the receptionist, you need to know that the work in question is not a great piece of fiction that begs to be read again and again. It’s “Always Hungry?”, a diet book that — according to two blurbs — explains “cutting-edge medicine” and “breaks new ground.”

But you won’t believe those blurbs if you read this column regularly.

Don’t hold that against the author, though. David Ludwig, MD, PhD., is a part of the medical world, so what he may have suspected years ago couldn’t be published until it was verified by stringent research repeatedly.

But athletic-performance innovators like John Parrillo can experiment less stringently and share the results immediately. I cite Parrillo in particular because some of his most important beliefs can be found in what Ludwig calls The Always Hungry Solution.

Even though it’s always dangerous to summarize a diet book of 347 pages in a single sentence, one from page 6 of “Always Hungry?” just might suffice: “Although a bottle of soda and a handful of nuts may have the same calories, they certainly don’t have the same effect on the metabolism.”

That’s correct, but hardly “cutting-edge.” For at least three decades, Parrillo has referred to this as nutrient partitioning, the theory that the three macronutrients — proteins, fats, and carbohydrates — are broken down, digested, and used in the body quite differently.

As a result, the “calories in, calories out” concept and “the notion that all calories are alike,” both of which impacted our nation’s eating patterns for decades, are — as Ludwig asserts — flawed.

But his assertion doesn’t really “break new ground.” It simply verifies the already established.

But that’s okay. Overall, the book serves as a blueprint for better eating and makes for interesting reading.

Take, for example, a study of Ludwig’s published in JAMA in 2012. It’s not only intriguing but also proof positive that Parrillo’s spot-on about nutrient partitioning.

Ludwig and his colleagues provided 21 overweight young adult subjects all their meals for seven months. After reducing their weight through diet by about 25 pounds, the researchers had each subject consume the same number of calories for three months — but the percentage of proteins, fats, and carbohydrates in those calories changed each month to approximate either the Mediterranean diet, the Atkins diet, or a generic high-carb diet.

During the months when the 21 ate as if they were on the Atkins diet, they burned an average of 325 more calories a day than when they were on the high-carb diet. While Ludwig doesn’t explain why this occurred, nutrient partitioning does.

Dietary fat and low-quality carbohydrates get stored as body fat easily; protein does not.

In fact, up to 30 percent of the highest quality protein gets “wasted” as it’s being digested. Twenty to 25 percent is typical for lesser forms.

Since the typical American eater who adopts the Atkins diet replaces, in essence, low-quality simple carbs with protein, calorie burn from digestion and assimilation increases. Since the Mediterranean diet replaces those low-quality simple carbs with healthy fats and high-quality complex carbs rather than protein, the difference in the burn rate is lower — but still statistically significant.

During the months that the 21 consumed the Mediterranean diet, they burned on average 150 more calories than the months they ate the high-carb diet.

In addition, Ludwig’s own personal story also attests to nutrient partitioning.

“After several years of steady weight gain,” Ludwig’s body mass index had him on the edge of being overweight. So he made a number of dietary changes, most notably “a cut back on [his] starchy staples, including bread, cereal, pasta, and pastries.

“Within a week [he] felt an astonishing improvement in energy and vitality, and a robust sense of well-being that lasted throughout the day.”

That, my friends, is what food should do for you.

But will Ludwig’s way of eating work for you?

If you adhere to it blindly, probably not. Even though I believe wholeheartedly in nutrient partitioning, for instance, a few of Parrillo’s other beliefs don’t work for me.

But if you’re willing to experiment a bit and make adaptations, Ludwig’s book could work wonders for you.