By the year 2050, we will have an estimated 9.7 billion people to feed. Let’s digest that for a minute, shall we? Such a figure seems to go completely against any idea of ‘sustainable’ food production, or a ‘sustainable’ diet, doesn’t it?

How do we sustain that many lives without causing the demise of our planet?

That is the challenge we are faced with in the agricultural sector, to produce food – and increased quantities of it, at that – and make such production more sustainable, more environmentally friendly, more carbon neutral, more climate beneficial. More, more, more.

We know that 30% of greenhouse gas (GHG) emissions, globally, come from agriculture – this is even higher in Ireland due to our agri-based food system and lack of big industry.

But the fact remains, without farmers and farming, we cannot feed the world. And without change, we risk destroying that world.

Sustainable diet and dairy

At a recent seminar involving the National Dairy Council (NDC), Kerry Agribusiness, Ornua and Teagasc, dietitian, Dr. Yvonne Finnegan took on the seminar title as her topic of discussion – ‘Dairy and its role in sustainable diets of the future’.

world milk day milk production scheme Dairy

Her message? Yes, dairy has a role in a sustainable diet.

Dr. Finnegan was already preaching to the convinced and the practising, given the audience, and the fact that the seminar was taking place on the farm Alex, Mary, Ita and Michael McCarthy – winners of the National Dairy Council (NDC) and Kerrygold Milk Quality Awards in 2021.

But she had some very interesting things to say about a sustainable diet, what it is, and how we can have one.

What is a sustainable diet?

So what is it? Well, it’s complicated. Like an onion, it has layers, so let’s get peeling.

One explanation often referenced – that a sustainable diet equates to a vegan diet – is far too simplistic, Dr. Finnegan said.

What is a sustainable diet?
According to the FAO, a sustainable diet is one which has with low environmental impacts, which contributes to food and nutrition security, and to healthy life for present and future generations.

“We cannot rule our diets by carbon footprint,” she said.

carbon footprint, carbon efficient beef

“If you look at some animal-based foods, you see that quite a few have medium greenhouse gas (GHG) emissions, are also highly nutritious, and we don’t eat huge quantities of them either. Equally, there are a lot of very low GHG foods but they are not good for our health.”

While acknowledging that veganism is a way of life for some – 2% in Ireland – Dr. Finnegan said it is a diet that is “not for the faint hearted”, and one that requires supplementation to add back in the essential dietary components that it simply cannot provide – vitamins, amino acids, and such.

A UK study last year, she said, showed that one third of new vegans are heavily reliant on ultra-processed foods. And increasingly, vegan diets comprise vegan sweets, vegan wines, vegan crisps – foods that are not necessarily produced in an environmentally friendly way.

The ‘cooked-from-scratch’ vegan-diet impression is not always an accurate one.

More than just about GHGs

So, a sustainable diet must consider more than just GHGs. Fair enough.

The Food and Agricultural Organization of the United Nations (FAO) recognised this several years ago, Dr. Finnegan said, and they arrived at four key pillars of what a sustainable diet should be: 

  1. Protective and respectful of biodiversity and ecosystems;
  2. Culturally acceptable and accessible;
  3. Economically fair and affordable;
  4. Nutritionally adequate, safe, and healthy.

We must address all four things as a whole – not each in isolation. For example, if it is unaffordable, then it’s not achievable; if it is not culturally acceptable, then it will fail. And, so on.

Interestingly, if we all tweaked our current diets so that we eat as is recommended by health professionals, we could reduce the size of our carbon footprint, Dr. Finnegan said.

She used the UK’s Eatwell plate concept to explain.

This ‘plate’ was devised to illustrate how much we should eat, from each food group, to strike a healthy and balanced diet.

Greater adherence to this healthy-and-balanced-diet advice could help reduce our GHGs by around 30%, said Dr. Finnegan.

“That shows you, if we were all to follow healthy-eating recommendations, it would be a win-win for planetary health and our own health.”

Discretionary foods

In the general conversation about the environment and the impact of agriculture on it, one thing that Dr. Finnegan said annoys her is the constant focus on animal-based foods.

“And yet, there are a lot of discretionary foods in our diet that we don’t need, they don’t provide any nutrition beyond calories, and are probably contributing to obesity,” she said.

A study carried out last year, and referenced by Dr. Finnegan, which, she said, had a huge amount of data on GHG emissions across a wide range of foods showed that, in the general population, meat is the biggest contributor to GHG emissions.

But, surprisingly, drinks – tea, coffee, soft drinks and alcohol – contributed the next 15% of GHG emissions, followed by dairy, followed by cakes, biscuits and confectionary.

“So, 15% come from foods that we don’t really need,” she said.


“We do need to look at these discretionary foods because they are not really bringing anything to the table in terms of nutrition but are certainly taking away from the table in terms of GHG emissions.”

Dairy is the safety net

Dr. Finnegan highlighted the difference in GHGs emitted between vegetarian and non-vegetarian diets, as per the aforementioned study, which showed around 40% fewer were emitted by the vegetarian diet.

But, interestingly, the dairy component of each diet remained the same.

“So, it is possible to still keep dairy in the diet and significantly reduce carbon footprint,” she said.

Referring to dairy as a kind of “safety net” in a vegetarian diet, she said: “When it comes to nutrition, dairy does pack  a big nutritional punch.”

Dairy’s contribution to the micronutrient intake of Irish adults is significant:

“It contributes over 50% of iodine, a good 25-30% pantothenic acid, vitamin B12, retinol, riboflavin, potassium, almost 50% of our calcium intake.” 

“So, you can imagine if we were to take that out of the diet in the morning, we would struggle to get them anywhere else.”

And, going back to one of those four pillars of a sustainable diet, she said that culturally, dairy is in our DNA:

“I found a quote from an 1185 Anglo Norman historian, who said, ‘this island is rich in pastures and meadows, honey and milk’. 

organic eggs Free range eggs poultry egg

“Dairy is in our DNA. The way we cook and the way we eat has been passed on for generations, it part of our culture.”

Sustainable Irish diet

The search for a sustainable Irish diet that adheres to the aforementioned four pillars is currently ongoing through the MyPlanetDiet Study at University College Dublin, where researchers are trialling a healthy diet that is good for us and good for our environment.

A sustainable diet is all about balance, and making some changes to diet, but tipping the scales in favour of a few more fruits and vegetables on our plate could make all the difference.