A macadamia nut is one tough nut.

Nearly all commercially sold are already shelled because it requires about 300 pounds of pressure per square inch of force to do so, roughly three to four times more force than is needed to crack a walnut. Try to shell a macadamia nut using a nutcracker designed for hazelnuts, almonds, and walnuts, and there’s a good chance the metal arms will bend or break.

That’s nuts.

So too is the fact that seven in 10 American adults are obese or overweight. Just as nuts is that it’s been that way for a good long time.

So you could say maintaining a healthy weight is also one tough nut. Expand upon that metaphor, and you could add that what America needs and has been unsuccessfully searching for is something far more efficacious than a standard nutcracker.

Something with more leverage.

Now you, my friend, can gain a good bit of dietary leverage — maybe even enough to crack your own overweight/obesity conundrum — by better leveraging protein. In other words, by acting in accordance with the protein leverage hypothesis.

Don’t let the technical language be a turnoff. Simply stated, the protein leverage hypothesis proposes that your body craves a certain amount of protein and that as a way to insure you get it, you will continue to feel hungry until that amount is consumed.

Even if you’ve already eaten enough food to maintain your current weight.

A Norwegian study to be published in the September issue of Appetite finds “strong support” for the protein leverage hypothesis “in line with previous studies in the field.” One of those previous studies, a randomized crossover trial published in the April 2025 issue of Nature Metabolism, focuses on ultraprocessed foods because one of the characteristics of most UPFs — besides containing the right mix of added sugars and fats to make them hyperpalatable — is that they tend to possess little protein.

So researchers recruited 21 young adults all determined to be in good health and on two different occasions had them spend 54 hours in metabolic chamber. That’s a room structured in such a way that a person’s oxygen inhalation and carbon dioxide exhalation can be measured precisely to determine energy expenditure, calorie burn, and nutrient usage.

Both times the participants were told to eat as much as they wanted during their stay, and the meals they were offered consisted heavily of UPFs accounting for 84 percent of the total calories.

During one of the 54-hour stays, however, the 84-percent UPF meals consisted of 13 percent protein and 46 percent carbohydrate; during the other, they consisted of 30 percent protein and 29 percent carbohydrate. Except for those two differences, the meals were always matched equally for calories, fat, and fiber and determined by the researchers to be “equally palatable.”

During each stay, the participants’ calorie intake was greater than the amount they expended, as you might suppose. But as Mike Murray notes in an article about the study for Examine, an independent online database that analyzes and summarizes scientific research, the overeating was 44 percent less on the high-protein diet when compared to the low-protein diet, and the difference averaged out to be 196 fewer calories per day.

Moreover, the researchers found during the time the participants ate the high-protein diet, they expended 128 more calories per day. Not through conscious or unconscious movement, mind you, but because of what’s known as the thermic effect of food: the energy your body uses to digest, absorb, and process the food you eat.

While TEF usually accounts for roughly 10 percent of your total daily calorie burn, that percentage is ultimately determined by another: the percentage of the macronutrients consumed during the day.

For ingested fats require to up to 3 percent of their calories to be “wasted” for digestion and carbs up to 10 percent. But depending of the types of proteins consumed, between 20 and 30 percent of ingested proteins are wasted in order for your body to use them to construct and repair muscles, organs, skin, and hair, serve as a secondary energy source, and a while lot more.

In short, the thermic effect of food is something you should never forget. But what’s important to remember from this study?

First and foremost, that virtually all UPFs, even those high in protein, induce you to eat more than you need to; therefore, placing a limit on your consumption of them, or eschewing them entirely, is a healthy move whether or not you need to watch your weight. Nearly as important, however, is that the idea inherent in the adage “not all calories are equal” also applies to UPFs.

That’s something you should never forget, either, especially after you contemplate the following. That the 2025 study found when the participants were told to eat as much as they want, they ate 196 fewer calories a day.

Over the course of a year, that equates to 20.5 pounds.

And that’s not peanuts.