Forty Years of Five-a-Day. What Did We Expect?

For roughly forty years, public health advice has told people to eat five portions of fruit and vegetables a day.

The message is correct. It is evidence-based. And it has barely changed.

In Ireland, around 30 percent of adults meet the five-a-day target,one of the stronger rates internationally. That still leaves the majority short.

Over the same period, Ireland has continued to carry a high burden of largely preventable chronic disease, including cardiovascular disease, alongside rising obesity and diabetes.

This did not happen because dietary advice was missing. It happened alongside it.

That distinction matters. It tells us the problem is not ignorance, and it is not that the science is wrong. Five-a-day is biologically sound.

What deserves scrutiny is the assumption that repeating correct advice is enough.

I spent more than twenty years working in global advertising, an industry built entirely around behaviour change. One rule was never in dispute: putting a message into the world does not mean people will act on it.

In advertising, targets exist, but they are internal. Sales figures, click-through rates, sign-ups. The public never sees them.

What people see instead are environments deliberately designed to make behaviour easier: defaults that reduce friction, cues that fit real lives, systems that assume people are busy, distracted, and inconsistent.

Public health has often taken the opposite approach.

We put the target front and centre, five-a-day, 10,000 steps, BMI thresholds, and expect the number itself to do the work. The target becomes the intervention.

But targets are not environments. And numbers do not compete well with time pressure, cost, habit, stress, or the food systems people actually live inside.

For forty years, we have treated guidance as delivery, and then expressed surprise when preventable disease continued to rise.

After four decades, five-a-day has reached what any advertiser would recognise as a ceiling. Awareness is high. Acceptance is high. Uptake has plateaued.

At that point, repeating the message is no longer a strategy. It is a refusal to engage with the harder work of design.

Health outcomes do not reflect what people are told. They reflect what is normal, available, affordable, and repeatable, day after day.

Five-a-day does not need to be defended. It needs to be relieved of the impossible task it has been given.

After forty years, the question is no longer whether the advice is right.
But whether we are willing to communicate in ways that actually change behaviour.

Heather McGuire | Culinary Medicine | Health Brand Consultant