Understand the upshot of this research, and you’ll understand why I continually encourage you to experiment with diet and exercise. But this research can also lead you to a second, equally important insight.

If you want to change your body, you need to change your mind.

Published in the July 2011 issue of Health Psychology, the study titled “Mind Over Milkshakes” is simple enough. Yale University researchers recruited 46 subjects to drink milkshakes on two different occasions.

Each time they took blood samples before the subjects read a full description of either the 620-calorie “indulgent” shake or the 140-calorie “sensible” one they were soon to drink, after they read the description, and after they drank the shake. Except the full descriptions the milkshake drinkers read were ... well, full of it.

Both shakes contained the same ingredients and 380 calories. Both shakes were exactly the same.

The blood samples taken after the subjects drank the shakes, however, were not. Those taken after the subjects believed they had consumed 620 calories created “a dramatically steeper decline” in ghrelin than those taken after the subjects believed they had consumed 140 calories - even though both times they had consumed the same amount of protein, carbohydrate, and fat in the same number of calories.

That such a deception led to a dramatically steeper decline in ghrelin is a really big deal.

When ghrelin circulates in your blood system, it signals to your brain the need to eat. As a result, there’s more of it in your blood when you feel hungry and less of it in your blood when you feel full.

But not in this study.

In this study, the amount ghrelin secreted and circulating in the blood system “was consistent with what they believed they were consuming,” not with what the subjects actually consumed.

Talk about role reversal. In this instance, ghrelin secretion didn’t affect the brain; the brain affected ghrelin secretion.

To explain the implications of the “Mind Over Milkshakes” study in a Runner’s World article, Amby Burfoot, a onetime Boston Marathon winner who’s a journalist and author, recalls a childhood scenario. “If your mother repeatedly says, ‘Eat your veggies, they’ll make you healthy,’ and you follow her advice, you’ll probably be healthy. But it might have very little to do with all the vitamins, minerals, and anti-oxidants crammed in broccoli.

It might be your strong belief that is making you healthy.”

While Burfoot makes a great point, the grand question remains: How do you develop strong dietary beliefs without prepubescent brainwashing by mom?

Experiment intelligently. Take the same analytical approach to your health and fitness 24 hours a day as a scientist brings to his studies.

Belief will arise from what you learn from that.

For years, I’ve been urging you to experiment intelligently for one specific reason I’ve dubbed the Snowflake Theory of Dieting: That the diet that works for you may not work for me because we all process and digest food a bit differently. This theory was just a well-reasoned guess when I first uttered it in response to a question in a health and fitness course I was teaching 35 years ago, but extensive scientific study - especially in the last decade or so and particularly of gut microbiota - shows it’s spot-on.

But another belief that I’ve held just as long, to eat small meals seven or eight times a day, now seems to be “spot-off.” A fair number of studies and a whole host of diet books argue that eating meals inside an eight-hour window and occasionally fasting for a full day or two is the optimal way to maintain a given weight and burn body fat.

But I’ve always been able to keep my weight where I want it and my body fat percentage really low doing essentially the opposite.

So is my situation just another example of what happened in the “Mind Over Milkshakes” study? Is my fervent belief in frequent eating causing my brain to send overriding signals to my digestive system to make a practice that should hurt my health help it?

I don’t know.

But I do know the Yale researchers write “mindset meaningfully affects physiological responses to food” to conclude the “Mind Over Milkshakes” paper, and I believe that is true. And if you do, too, the implications of that belief could make you a bit awestruck, maybe even a little intimidated.

Because that belief puts the onus directly on you.

It means when it comes to matters of fitness and health, you, and you alone, are in charge. You’re the boss. You have total sovereignty over yourself.

So if you’re out of shape, consistently sick, or just occasionally grumpy, you have no one to blame except yourself.

But there’s really no need to blame, just a need to change your beliefs and take full advantage of the awesome, albeit intimidating, power of the mind.