An Analysis of Portion Size Experimental Data in Ireland


Using surveys and tests to compare recommended to actual portion sizes and increasing awareness through education.


The aim of the project was to look at portions and compare what people eat to what they should be eating. To do this, surveys were carried out to ask people what they thought about portions and tests to measure how much food they are actually eating compared to what they should be. Contact was made with cereal manufacturers, supermarkets and government departments to see what can be done to tackle the issue.
Both the test and survey results show that people eat portions that are in excess of what is recommended. Only twelve percent of people base their portions on the recommended amount. People think the recommended portion for pasta is 248% the actual recommended. All of this can have devastating effects for people. If you never look at the portions on food you are more than twice as likely to be overweight than someone who does (2.3 times).

Talking to the Experts:

Dr Carol Ní Chaoimh and Fionnuala Muldoon were consulted for their professional opinions on portion sizes. On Friday the 16th of December Dr Ní Chaoimh, Post Doc Researcher on Human Nutrition in University College Cork discussed the project and its implications. She was very interested in the project and what was being done. The meeting started off by asking her how much she felt people are aware of portion sizes. She said that people are not at all aware of portion sizes especially with foods that are not broken into distinguishable units. This backed up what has been found in the research: people are more likely to eat the correct size of sliced pan bread which is broken into units compared to something like muesli which is not. (Muesli = 326% Bread = 115%)
She was then asked if there were people who were trying to eat healthily but failing to do so by eating too much of the “right” foods. It was agreed that people tend to fall into three groups on this issue. The first group do not think about healthy eating and as a result have a poor diet. The second group are aware of healthy eating and for the most part make a conscious effort to eat healthily, however they eat portions that are too big and as a result their diet is not as satisfactory as they would have wished. Information is key to this group and if they have easy access to information about portion sizes they will as a result make an effort to eat the correct portions. The third group, the so-called “food warriors” are exceptionally conscious of what and how much they eat and as a result have an excellent diet. She said that most people fall into the second group and, if they were given a little help, they could make great improvements to their diets. She also said that people do not think of how much they are eating of “good foods” and think they can eat as much of the food i.e. brown bread as they want without any consequences because the food is considered “healthy”. She said that people need to be aware that you can have too much of a “good” food.
When asked what advice she would give to people to control their portions, she said that that when people are eating a meal they need to be conscious of the proportions of different foods on their plates, (to have more vegetables and less carbohydrates and meats). If people want to eat healthy they need to go out of their way to inform themselves about portion sizes. She said this can be very hard to do for ordinary people as it can be very hard to find information on portions which is often tucked in some corner of the internet and can take ages to find what you want.
The last question to Dr Ní Chaoimh was what she would like to see the government do to help people eat the correct portions. She said that portions should be given in the form of an image as well as in unit form as people find it easier to understand and refer to images. She said that a “supersize tax” is a viable option worth consideration. There would be many different ways to implement such a measure such as taxing manufacturers who market products above a certain size to one person. It would be perfectly acceptable to sell these products in larger sizes as long as they were properly marketed and labelled. She said that restaurants should offer smaller portions to give people the option when they are eating out. She said it is very important that children eat the correct portions while they are still growing up. It is especially crucial that children eat well when they are functioning on hunger cues (eating when they feel hungry), so that when they are responding to food cues (when they see food, and at certain habitual times of the day i.e. lunch around 1pm) they carry those good habits forward.
On the 21st of December Fionnuala Muldoon, a Medical Dietitian, discussed the project and portion sizes at Cork University Hospital. To start with she discussed what resources are currently available to people.
She said that the dietitians in the hospital liked to use analogies such as a palm of your hand for meat and a matchbox sized slice for cheese to help people understand portions better. She said that visual aids such as a cup are much more practical and easier to visualize than using units like grams. She said that a good tip for people trying to lose weight is to split up your plate, half for vegetables, a quarter for carbohydrates and the remaining quarter for protein. For people who are at a healthy weight they can split their plate three ways between vegetables, carbohydrates and protein.
She was asked what nutritional advice people are given at the moment with regards to portions. She showed some of the resources they give to people such as the updated food pyramid. She said that this was a step in the right direction by the government. However when the new food pyramid was displayed in the media the day after it was published the Irish Independent printed it without the portion information. She said that people know what healthy eating is and what foods they should be eating but eat portions that are too big. She said that much of her work involves teaching people how to plan so that they do not need to be worrying about what to eat when they get home.
When asked what the government should do she had several suggestions. She said that the government is currently trying to do something but to little avail. She recommended that the traffic light system used in the U.K. should be introduced in Ireland and it needs to be standardised, presently some manufacturers are doing it here but there are variations between them. If the traffic light system was properly introduced it would let people understand properly what is in a recommended portion. She also said that a taxation model should be considered such as one which placed excise on sweets and that this money would be used to subsidise a tax reduction on vegetables and fruit. She said the one of the key drivers of the current obesity crisis is the easy availability of cheap unhealthy foods from ready meals to chocolate bars.
She said that eating portions that are too big this could result in
•heart disease
•cellulites and foot ulcers
•heart attack
•worse post-operation outcomes
•mobility issues
•breathing difficulties
Finally she said that they get people to weigh out their food and keep a food diary for a week and this can dramatically improve a person’s diet but even just by measuring a portion out once you can become vastly more aware of how much you are eating in the future.


For the test, the participants were asked to pour a bowl of breakfast cereal into a bowl that reflects their eating habits. This was weighed and recorded and the process was repeated with different types of cereal. This method was chosen after much consideration of other methods such as image analysis.[1] Participants had a choice of bowls so that they could choose one most like they use at home so they could pour a bowl just as they do at home. There were seven different types of cereals to choose from so people could pick one that reflects what they have at home. These cereals were chosen because they are widely eaten and each represents many other brands which have the same type of cereal with the same shape and density.
Participants could not see their results until they were completely finished with the test otherwise seeing their results might affect how much they were pouring. Participants could not see how much the others were pouring so that it would not affect how much they were pouring. Participants were also told not to discuss how much they poured until after everyone was finished so that they wouldn’t affect anyone who was yet to go.
145 people completed the test. The sample of people used was selected using simple random sampling as per the survey; the test has a spread of people and is nationally representative for Ireland.

The following five charts show what people think a portion is compared to the recommended. The units used for the pasta, rice and cereal was a 200ml plastic cup which participants were shown, the unit for butter used was a teaspoon and slices were used for bread. The aforementioned bar chart which shows that people think the recommended portion for cereal is an extra 75% of what it actually is.

This chart shows that people think that the recommended portion for pasta is two and a half times bigger than what it actually is.

The data for rice is quite similar to pasta with people thinking the recommended portion is more than twice as big compared to what it actually is.

People think that the recommended portion for butter is 64% greater than what it should be. Although it is too much, it is less than for other foods. It seems clear to me that the old message of fat being the enemy the is still ingrained into people and they are more wary of it than they are of carbohydrates or sugar.

People think at the recommended portion for bread is only 15% greater than the recommended. Most people eat the recommended portion of sliced pan because it is broken into easily distinguishable units: the humble slice. When people say something is the best thing since slice pan they usually fail to see its beauty from a portion point of view, it is so easy to tell how big a portion is. Although bread has its nutritional faults and failings at least people know how big a portion is so they are armed with all the information they need to decide to eat some or not.
If it was as clear with every food what a portion is we probably would not be facing down the barrel of the obesity crisis that is currently facing us.

The graph below shows how many people who were right or wrong when they were asked how big a portion is. The blue signifies people who said the wrong portion and incorrectly thought a portion is smaller than the correct answer. The green is for people who said the correct portion. The red shows people who said the wrong portion and incorrectly thought a portion is bigger than it is. As you can see most people thought a portion is much bigger than it is for rice, pasta and cereal. Most people were correct when asked how big a portion is for bread.

Relationships between Variables:

These charts look at how the answer to one question affects the result of another such as how stress levels affect portion sizes. The bar chart below shows just that; you are three times more likely to have portions that are way too big if you are very stressed (7 or above) compared to if you are less stressed (3 or below).

This bar chart below shows that you are 50% more likely to be in very good health if you always read the nutritional information on packaging compared to people who never do it.

This final chart regarding the survey results shows the relationship between portion sizes and annual sick days. It shows that people who eat portions that are too big or too small miss more days than people who eat the right amount. If you eat portions that are the right size you are less likely to get sick. Eating portions that are too small makes it likely that you will have many more sick days. This shows us that it is as important to be wary of portions that are too small as well as ones that are too big.

Test Results: This bar chart shows the results of the tests. It shows how much more people eat compared to what the recommended portion is.


  • Ireland is suffering from an obesity crisis. Efforts are being made to combat this but so far these have been more or less useless. Something needs to be done. Most people try to eat healthily but eat portions that are too big. If we as a nation can fix the portion problem we can win a key battle in the war against obesity.
  • The main conclusion is that people eat portions that are too big and this is a major issue. They are heavier, getting sick more and enjoying a lower quality of life then what they deserve. Only one in ten people base their portions on the recommended and people think the recommended is far bigger than it actually is.
  • From speaking to experts in the field and from the surveys, it is know that there are lots of people who eat “good” foods because they want to eat healthily but eat too much and end up losing the benefits of the healthy food. An apple a day may keep the doctor away but some people do not realise that more is not always better.
  • People have the biggest portions for the densest foods such as muesli and have bigger portions for foods that are not broken into distinguishable units compared to foods that are.
  • Stress is a factor in the portions we eat. More stressed people tend to eat bigger portions.
  • Even if you want to eat the right portions it is hard to get the information you\’re looking for especially if you are time strapped or tech illiterate.
  • People do not like having portions listed in grams/millilitres and they often find it confusing to understand or relate to.
  • The average portion that people eat for granola is 326% the recommended and people eat portions that are too big for all the foods looked at.
  • The media often focuses on what people eat and fails to look at how much people eat.
  • Manufactures and Supermarkets are not interested in helping fix the problem as it does not directly affect them. It would take governmental action or the will of consumers to get them to make a difference. [2] [3]

Irish National Recommendations:

Portions should be given in the form of an image as well as in grams/ml as people find it easier to understand seeing how big a portion should be.
Every household in the country should have a 200ml plastic cup which they could use to measure portions.
Everyone in the country should try weigh out their portions at least once as this will give them a better understanding of portions in the long run.
There is excellent advice about portion sizes out there but few people know about them, the government needs to promote this advice and to send the message out to the public. [4]
An educational strategy must be devised so people do not just learn what foods they should eat but also how much of it they should eat. The new food pyramid is great but it must be the start of something bigger.
The legislation regarding food packaging needs to be updated so that nutritional information is easier to read, bigger font etc.
The traffic light system brought in to the UK should be properly introduced here and standardised.
For cereal bowls to have markings on the side to show how big a portion is and for the plates with lines separating the sections for protein, carbohydrates and vegetables to be sold more widely.
For foods such as pasta and cereal to be packaged in separate (biodegradable) plastic bags so that one bag is equal to one portion.
Ultimately, everyone has the responsibility to educate themselves but as a nation steps must be taken to make it easier for people to do just this.


[1] “Determination of Food Portion Size by Image Processing” by Mingui Sun, Qiang Liu, Karel Schmidt, Jie Yang, Ning Yao, John D. Fernstrom, Madelyn H. Fernstrom, James P. DeLany, and Robert J. Sclabassi
[2] “How Food Marketers Can Sell Smaller Portions: Consumer Insights and Product Innovation” by J.Riss and colleagues.
[3] “Downsizing: Policy Options to Reduce Portion Sizes to Help Tackle Obesity” by Theresa M Marteau, Professor Of Behaviour and Health, Gareth J Hollands, Senior Research Associate,  Ian Shemilt, Senior Research Associate and Susan A Jebb, Professor Of Diet and Population Health.
[4] “Serving Size Guidance for Consumers: Is It Effective?” by G. P. Faulkner, L. K. Pourshahidi, J. M. W. Wallace, M. A. Kerr, T. A. McCrorie and M. B. E. Livingstone.

About the Author

Tony O\’Halloran, Ireland
Tony O\’Halloran is a 17 year old student from Ireland. He has presented recent research to members of the Irish Cabinet advising them on policy issues. Recently he qualified for the European Youth Parliment National Final, the Matheson Irish National Debating Competition as well as being part of the winning Irish National Vex Robotics Team. Currently he is working on the multi award winning

Leave a Comment

Your email address will not be published. Required fields are marked *