It may be a bit of a stretch to make an analogy between optimal eating and an amusement park, but one thing is for sure. Cataloging the last 70 or so years of research about the ingestion of eggs and the cholesterol that comes with them makes you feel as if you’re riding the merry-go-round.

For much of the second half of the 20th century, run-of-the-mill medicos told you to limit yourself to an egg (or maybe two) a day because the high amount of cholesterol in them could very well skyrocket your body’s own cholesterol level and lead to heart disease in not eaten in moderation. But then the research that followed showed that not only does the ingestion of saturated fat affect your cholesterol levels more so than the ingestion of dietary cholesterol, but also that your body increases its production of it when it’s lacking in your diet.

As a result, for the last 15 years or so, moderate and regular consumption of eggs has been encouraged because eggs contain the best source of bioavailable protein and contain a fat that promotes brain health. In fact, since 2015, the government has suggested no limit on the number of eggs people consume in a week.

But now the merry-go-round has come full circle and the latest research suggests that eating eggs does indeed increase body cholesterol levels as well as lead to heart disease.

Researchers from Northwestern University Feinberg School of Medicine in Chicago, IL, with the help of a few others analyzed six prior U.S. studies incorporating nearly 30,000 people. Their work was published this March in JAMA and co-corresponding study author Norrina B. Allen Ph.D., an associate professor of preventive medicine at Northwestern, summed up their findings this way: “People who consume less cholesterol have a lower risk of heart disease.”

What does this new study mean? I don’t know. I’m still of the belief that unless there’s a history of heart disease in your family, eating two or three eggs four or five times a week in conjunction with an overall diet that’s low on saturated fat helps rather than hurts your health.

But I do know what this new study creates. Confusion.

It’s the same sort of confusion that comes from the last 70 or so years of coffee research and its key constituent, caffeine. It too takes you on a metaphorical merry-go-round ride.

At first, you were told to limit yourself to a cup (or maybe two) a day because the caffeine in coffee created high blood pressure levels that created hypertension and led to heart disease. But then subsequent research contradicted that, and further research found that drinking four cups of coffee a day or more actually led to a significantly lower risk of developing a disease now running rampant: type 2 diabetes.

In 2016 a study from the University of Ulster in Coleraine, United Kingdom added additional support to the belief that had recently been accepted: that the health benefits of drinking two or three cups of coffee a day clearly outweighed the potential risks previously associated with it.

And the good news for coffee drinkers continued.

More recent research suggests that coffee consumption actually offsets the mental decline that comes with age. But in this study published in the journal Frontiers in Neuroscience, the researchers led by Dr. Donald Weaver, who is co-director of the Krembil Brain Institute in Toronto, Canada, found that it wasn’t the caffeine fighting cognitive decline.

It was the compounds released in the roasting process.

While you may not care what compound in the coffee is helping you, the fact that it isn’t the caffeine is significant.

That’s because caffeine is the key ingredient in energy drinks, and a study of them found that drinking energy drinks not only alters heart rhythms but also adversely affects blood pressure.

While it must be noted that most energy drinks contain other ingredients, especially taurine, that could be responsible for this, the amount of energy drink used in the study, 32 ounces, contains enough caffeine to create the problems associated with overconsumption: increased heart rate, jitteriness, nausea, and insomnia.

Keep in mind, however, that Will Brink — a Harvard University graduate, creator of the Brinkzone Blog, and writer of countless health articles and even a couple of books, says, “Caffeine positively impacts memory, performance, endurance coordination and increases arousal, vigilance, while reducing fatigue.”

In short, this column concludes the way so many others do: with a plea for you to take what you’ve just read, apply it to your own set of circumstances, and experiment. When used intelligently, the consumption of eggs and coffee can enhance your health.

And the well-timed ingestion of “straight” caffeine can certainly increase the length and intensity of your workouts.