Maryrose is a 47-year-old mother of two from California.
She’s fit and healthy — she gets regular checks at the doctor’s office every few months. And by all conventional measures — things like weight, blood sugar and cholesterol levels — she’s in top shape.
But Maryrose has an unusual habit.
“It’s now been almost 13 years and I’ve been eating a pint of ice cream every night,” she says.
She’s a purist — vanilla only, thanks. And Maryrose says the nightly ritual is as much about winding down and relaxing as it is about the ice cream itself.
Her pint-a-night habit started when she was pregnant with her first child. After finding it didn’t seem to affect her health or energy levels, she never stopped.
Searching for answers online
How could it be that someone eating a pint a night bucks the conventional wisdom on what’s good for your health?
But what is healthy? And how can we make empowered decisions about what we eat? That comes down to two factors: understanding how evidence works, and what role food plays in our lives.
Looking for advice, Maryrose asked an online forum of doctors whether ice cream could ever be healthy.
It might seem a silly question at first glance — but she got back more than she bargained for.
“They pretty much were uniformly saying that this was a bad idea, I can’t do this, maybe I’m fine now, but, you know, I’m gonna get diabetes, I’m gonna clog my arteries,” she says.
But among the responses was an article pointing to a complex and contested idea in nutrition science.
It discussed mixed evidence showing that in some cases, ice cream could have a protective effect against some negative health outcomes — such as diabetes and heart disease.
What does the evidence say?
Multiple scientific studies show a positive association between ice cream and health.
When diets are tracked and people are followed for a long time it appears that those who eat ice cream more often have a lower risk for type 2 diabetes and even cardiovascular disease.
But there are scientific reasons the effect seen in these studies might not actually be “real” — a statistical anomaly rather than something that is happening in the real world.
The studies looked at this “ice cream paradox” are observational studies, where people are followed over time. That’s distinct from randomised controlled trials, experiments where you split people into groups and give them different treatments or interventions.
Observational trials can’t prove that ice cream has a protective effect on our health. They can only show that the two things are linked.
Weighing up the good with the bad
Dr Mozaffarian is director of the Food and Medicine Institute at Tufts University and has been involved in some of the studies finding health effects linked to ice cream.
“You get what’s called reverse causation, where … people who are less well and worried about their glucose tend to avoid ice cream, and so that could be why ice cream seems protective,” he says.
There are also published studies that show the opposite effect — a negative association of eating ice cream and health.
The studies that show benefits are typically from Western nations like the US. The ones showing no benefit or increased risk are from Asian cohorts such as South Korea.
